SA Respiratory and CV Flashcards

1
Q

What is the function of a cough?

A

Removes material from airways:
Assists mucociliary clearance
Expels inhaled material
Protects against inhaling particles/inhalants

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2
Q

Where are mechanoreceptors located?

What about chemoreceptors?

A

Mechanoreceptors: larger airways
Chemoreceptors: medium airways

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3
Q

Where are cough receptors most numerous?

A

Larynx > trachea > bifurcation > bronchi

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4
Q

Give some common differential diagnoses of coughing

A

Compression of mainstem lobar bronchi (eg left atrial enlargement)
Stimulation of cough receptors (eg tracheal/laryngeal/bronchial disorders)
Excessive mucous/fluid/inflammation (eg pulmonary oedema, pneumonia, bronchopneumonia)

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5
Q

Chronic bronchitis is mainly seen in which kinds of dogs?

A

Small breed dogs

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6
Q

How should a cat’s thorax feel when compressed?

A

Springy

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7
Q

What might you see on a radiograph of a dog with chronic bronchitis?

A

‘Tram lines’

Rings- thickened bronchial walls

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8
Q

Give some characteristic changes to the bronchi caused by chronic bronchitis

A
Excessive mucous production
Damage to cilia
Increased goblet cell numbers
Hyperplasia of submucosal glands
Loss of ciliated epithelium
Squamous metaplasia of mucosa
Secondary infections are common
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9
Q

How does a dog with chronic bronchitis present?

A

Chronic cough with attempts at production

Worse on excitement

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10
Q

Can you cure chronic bronchitis?

A

No, therapeutic goal is to manage it with bronchodilators and steroids (anti-inflammatory glucocorticoids). Avoid systemic steroids to prevent weight gain

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11
Q

How can you investigate a suspected chronic bronchitis case?

A

Thoracic radiographs
Haematology
Bronchoscopy
Bronchoalveolar lavage to obtain samples for cytology/bacteriology/parasitology

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12
Q

When doing a bronchoalveolar lavage in a dog, how much saline should you use?

A

1/2ml per kg bodyweight

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13
Q

If you see worms on a tracheobronchoscopy what are they likely to be?

A

Crenosoma vulpis (fox lungworm)

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14
Q

When you do a bronchoalveolar lavage, how much fluid should you expect to aspirate back?

A

50%

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15
Q

What cells are normal to see on a BAL fluid analysis?

A

Goblet cells

Ciliated columnar epithelial cells (CCECs)

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16
Q

If you see macrophages containing bacteria on a BAL fluid analysis, what does this tell you?

A

There is an active infection

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17
Q
What are the normal values in BAL fluid analysis for:
WBC
Macrophages
Neutrophils
Lymphocytes
Eosinophils
A
WBC: <5x10^9/l
Macrophages: 70%
Neutrophils: 20%
Lymphocytes: 10%
Eosinophils: <20-25%
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18
Q

What would you see on a cytology of BAL fluid in chronic bronchitis?

A

Increased mucous, neutrophils, macrophages
Possibly squamous metaplasia of normal ciliated columnar epithelial cells
Presence of bacteria/particulate matter

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19
Q

If you do a BAL in a dog with chronic bronchitis and you see Simonsiella, what does this mean?

A

Oral contamination

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20
Q

How can you manage chronic bronchitis (non-medically)?

A

Weight control
Harness rather than collar
Avoid irritants/smoking environment
Mucous is easier to shift if hydrated-avoid dry environments

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21
Q

Give the functions of bronchodilators

A

Reduce spasm of lower airways
Reduce intra-thoracic pressures
Reduce tendency of larger airways to collapse
Improve diaphragmatic function
Improves muco-ciliary clearance
Inhibit mast cell degranulation (reduced release of mediators of bronchoconstriction)
Prevent microvascular leakage

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22
Q

Give some functions of glucocorticoids

A
Anti-inflammatory
Broncho-dilatory
Inhibit prostaglandin synthesis
Potentiate beta-2 adrenergic activity -> bronchodilation
Reverse increased vascular permeability 
Alter macrophage function
Modulate the immune system
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23
Q

Would you give antibiotics when treating chronic bronchitis?

A

Most chronic bronchitis cases are not caused by bacteria
Only give antibiotics if secondary infection is possible, or if culture and sensitivity results are positive, or if intracellular bacteria are seen on BALF cytology

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24
Q

If you decide to use antibiotics when treating respiratory tract infections, what criteria should it fit?

A

Needs to concentrate in the lung
Needs to be effective against resp. pathogens
Should be bacteriocidal
Need to treat for 3 weeks minimum

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25
Q

Give some examples of antibiotics used for respiratory infections

A

Clavulonate potentiated amoxicillin (broad-spectrum)
Cephalexin (mainly gram -ves)
TMP sulphonamides (broad-spectrum)
Fluoroquinalones (broad-spectrum)
Clindamycin (mainly gram +ves and anaerobes)
Doxycycline (Mycoplasma or Bordatella)
Metronidazole (anaerobic, some bronchopneumonias)

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26
Q
Eosinophilic bronchopneumopathy (EBP) usually affects which kinds of dogs?
What is thought to be the cause?
A

Young dogs, large breeds

Hypersensitivity to inhaled allergens

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27
Q

What would you see on a bronchoscopy of a dog with eosinophilic bronchopneumopathy?
What would you see on a BALF cytology?

A

Copious amounts of yellow-green mucous

Lots of eosinophils (>25%)

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28
Q

How do you treat eosinophilic bronchopneumopathy?

A

Prednisalone (2mg/kg/alternate days) (immunosuppressive)

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29
Q

Why do cats have an expiratory dyspnoea with feline asthma?

A

The bronchioles are more constricted during expiration

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30
Q

How does the chest of a cat with feline asthma differ on a radiograph?
What should you also look out for?

A

Chest is more concave

Look out for fractured ribs (cats can be so dyspnoeic that they fracture ribs)

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31
Q

How can you care for a dyspnoeic cat with feline asthma?

A

Minimise stress
Provide humidified oxygen
Give IV steroids
Bronchodilators (eg terbutaline)
Consider MDI (metered-dose inhalers) administration of bronchodilators (salbutamol, fluticasone)
Severe life-threatening distress: adrenaline
Chronic cases: prednisolone

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32
Q

What kind of coughing is seen with bronchial foreign bodies?

A

Sudden onset

If long-standing, may be halitosis

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33
Q

What is orthopnoea?

A

Extreme form of dyspnoea

Animals have to sit up/stand to breathe and adopt an air-hungry position with abducted elbows

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34
Q

Give some differential diagnoses of inspiratory dyspnoea

A

Laryngeal neoplasia/paralysis

Tracheal mass/stenosis

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35
Q

Give some differential diagnoses of expiratory dyspnoea

A

Feline asthma

Dynamic airway collapse (small airway collapse; only hear wheezing with stethoscope)

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36
Q

Give some differential diagnoses of both inspiratory and expiratory dyspnoea

A

Pulmonary parenchymal disease (eg pneumonia)
Pleural effusions
Pneumothorax
Pulmonary thromboembolism

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37
Q

What kind of disease causes restrictive dyspnoea

A

Pulmonary and pleural disease

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38
Q

Does restrictive dyspnoea occur on inspiration or expiration?

A

Both

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39
Q

What kind of obstruction is present with obstructive dyspnoea on inspiration and expiration?

A

Inspiration: upper airway obstruction
Expiration: bronchial narrowing

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40
Q

When giving oxygen therapy, what should the value of inspired O2 be?
Why should you avoid 100% oxygen for more than a short time?

A

30-50%
Oxygen toxicity
Oxygen must be humidified

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41
Q

Pneumonia in small animals is usually associated with what?

A

Broncho-pneumonia

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42
Q

Give some causes of aspiration pneumonia

A

Megaoesophagus
Laryngeal paralysis
After tie-back surgery

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43
Q

Regarding pneumonia, what does a ventral distribution (on radiograph) suggest?

A

Airway disease or aspiration as the initiating factor

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44
Q

Regarding pneumonia, what does caudodorsal lung involvement (on radiograph) suggest?

A

Haematogenous spread

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45
Q

What is pneumocystis carinii?

What does is respond to?

A

A yeast-like fungus
Causes pneumonia
Cavalier King Charles puppies have immunoglobulin deficiency and may present with dyspnoea due to pneumocystis carinii pneumonia
Only responds to TMP sulphonamides

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46
Q

Where is angiostrongylus vasorum found in the dog?

A

Pulmonary vessels

french heartworm

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47
Q

A ‘goose honk’ cough is associated with what?

A

Tracheal collapse

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48
Q

When radiographing a mass on the right lung lobe, which view should you use?

A

Left lateral

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49
Q

When is it safe to do a lung mass aspirate?

A

If you’re not going through air-filled lung
If the mass is next to the chest wall (or risk pneumothorax)
Can be ultrasound-guided

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50
Q

Idiopathic pulmonary fibrosis typically affects which dog breeds?

A

Terriers, especially west highland white terriers

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51
Q

Describe the presentation of idiopathic pulmonary fibrosis

A

Slow, insidious progression
Inspiratory and expiratory dyspnoea, rapid shallow breathing, can develop rectus abdominis hypertrophy and become cyanotic on minimal exertion
Characteristic ‘crackles’ (inspiratory) on lungfield auscultation (dynamic airway collapse)
Become severely disabled
Active inflammation on CT scan

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52
Q

How do you treat idiopathic pulmonary fibrosis?

A

Symptomatic support-nothing proven to be effective
General management: restrict exercise and excitement
Bronchodilators? (esp if dynamic airway collapse or concurrent chronic bronchitis)
Anti-fibrotics? (eg colchicine)
Steroids? (prednisolone)
Home O2 delivery? (when distressed)

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53
Q

Describe paraquat poisoning

A

Weedkiller, severe pneumotoxin
Severe dyspnoea
Initial alveolitis progresses to severe pulmonary fibrosis
Very poor prognosis-PTS

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54
Q

Is pulmonary thromboembolism usually primary or secondary?

A

Secondary to underlying systemic disease eg IMHA, DIC, PLN, Cushings, pancreatitis, sepsis (not usually cardiac dz)
(losing protein -> lose clotting factor -> clots more likely)

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55
Q

When should you suspect pulmonary thromboembolism?

A

Sudden onset dyspnoea

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56
Q

How can you confirm pulmonary thromboembolism?

A
Blood gas analysis 
Coagulation screen (including D-dimers)
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57
Q

How do you treat pulmonary thromboembolism?

A

O2 supplementation
Sedation/anxiolytics
Treat underlying disease (eg DIC)
Anticoagulant treatment to prevent further episodes (eg heparin)
Anti-platelet medication (eg clopidogrel)

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58
Q

What is ARDS (acute respiratory distress syndrome)? Give some initiating factors

A

Non-cardiogenic pulmonary oedema
Respiratory distress with alveolar infiltrates on radiographs
Pneumonia, electrocution, smoke inhalation, near drowning, trauma, sepsis, DIC

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59
Q

Should you be concerned if you see pleural plaques on a radiograph?
What do they look like?

A

No-they are incidental findings

Small, white, calcified, dense, 1-2mm

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60
Q

What is a holter monitor?

A

Records ECG for 24 hours

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61
Q

Give some cardiac causes of episodic weakness/syncope

A

Compromised cardiac output

  • Congenital heart disease (esp aortic stenosis, patent ductus arteriosis)
  • Dilated cardiomyopathy
  • Hypertrophic cardiomyopathy (cats)
  • Cardiac tamponade
  • Cardiac neoplasia

Cardiac arrhythmias

  • Tachyarrhythmia
  • Bradyarrhythmia
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62
Q

Give some causes of tachyarrhythmia

A
Atrial fibrillation
Supraventricular/atrial premature complexes
Ventricular premature complexes
Supraventricular tachycardia
Ventricular tachycardia
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63
Q

How would atrial fibrillation appear on an ECG?

A

No p waves
Irregularly irregular ventricular rhythm
Normal narrow QRS complexes (as arrhythmia is originating above AV node)

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64
Q

What is atrial fibrillation associated with in small animals?

A

Cardiac disease-atrial stretch

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65
Q

How do you treat atrial fibrillation?

A

Treat underlying cardiac disease and aim to control ventricular response to the AF
To control, you can use digoxin, beta blockers (not if underlying CHF), Ca2+ channel blockers

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66
Q

What is digoxin?

A
Weak positive inotrope (increases heart contractility)
Negative chronotope (slows HR)
Enhances vagal tone (slows down no of waves of depolarisation that reach the ventricles)
Indicated for:
-Atrial fibrillation
-Other supraventricular arrhythmias
-Sinus tachycardia
-Poor systolic function
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67
Q

Why should you be careful when increasing the dose of Digoxin when treating atrial fibrillation?

A

Toxicity; need to add Diltiazem (calcium channel blocker)

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68
Q

When treating atrial fibrillation with Digoxin, what should the desired digoxin level be after 5-7 days?

A

0.5-0.9 ng/ml

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69
Q

What is Diltiazem?

A
Calcium channel blocker used to treat atrial fibrillation
Negative inotrope (reduces contractility but this is rarely a problem)
Vasodilator (as affects vascular smooth muscle as well as myocardium)
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70
Q

When Digoxin and Diltiazem are used together to treat atrial fibrillation, which drug starts to work first?

A

Diltiazem

Digoxin kicks in after a week

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71
Q

Should you ever use beta blockers to treat uncontrolled CHF?

A

NO

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72
Q

Describe emergency treatment of supraventricular tachycardia

A
Vagal manoeuvres (apply gentle pressure to eyeballs, carotid sinus massage under jaw)
IV Esmolol (beta blocker)
IV Verapamil (Ca2+ channel blocker)
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73
Q

How would conduction via the accessory pathway appear on an ECG?

A

Short P-R interval

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74
Q

‘Delta’ waves can occur in animals with which heart condition?

A

Supraventricular tachycardia caused by Wolff-Parkinson-White syndrome

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75
Q

Give some underlying causes of ventricular ectopic focuses

A

Underlying cardiac disease; CHF (ischaemia, myocardial hypoxia etc)
Acidosis
Hypokalaemia
Catecholamines (eg stress, pain etc)
Abdominal disease (GDV, splenic lesions, sepsis, perforated gastric ulcer, pancreatitis etc)
Thoracic trauma (myocardial contusions)

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76
Q

When should you treat ventricular ectopics?

A

If it is haemodynamically significant
If HR is very fast/there is close coupling/’R on T’
If multifocal
Monitor with halter

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77
Q

What are the 4 classes of anti-arrhythmic drugs?

A

Class 1: sodium channel blockers (slows uptake of action potential)
Class 2: beta-blockers
Class 3: potassium channel blockers (delays repolarisation/lengthens action potential duration)
Class 4: calcium channel blockers (act on SAN or AVN) (treat supra-ventricular arrhythmias)

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78
Q

How would you treat a ventricular tachyarrhythmia?

A

Lidocaine (IV boluses; sodium channel blocker)
Sotalol (oral beta blocker)
Mexilitine (oral; sodium channel blocker)
Amiodarone (oral; potassium channel blocker)

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79
Q

How would you identify atrial standstill on an ecg?

A

No p waves
T waves are spiky and symmetrical
Normal QRS complexes

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80
Q

How would you identify a 2nd degree block on an ecg?

A

Non-conducting P wave, 3-4 normal QRS, non-conducting P wave

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81
Q

How would you identify a 3rd degree block on an ecg?

How would you treat?

A

Atria and ventricles are depolarising independently
P-P intervals are regular
QRS complexes have a regular R-R interval
P-R interval is varied
(Impulse generated in the SAN does not propagate to the ventricles)
Tx: Pacemaker

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82
Q

How would you identify a 1st degree block on an ecg?

A

Long P-R interval

Impulse travelling from atria to ventricles is delayed and travels slower than normal

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83
Q

How would you treat bradyarrhythmias?

A

Exclude/treat underlying disorders (eg hyperkalaemia, hypothyroidism etc)
Vagally mediated? Try response to anticholinergics: atropine response test (expect >50% increase in HR after 30-40 mins)
Life threatening: b-agonist eg isoproteranol or b2-agonist eg terbutaline
Oral meds: anticholinergics (eg atropine, propantheline), beta sympathomimetics (terbutaline), xanthine derivatives (eg theophyline)

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84
Q

Why would we measure blood pressure?

A

Anaesthetic monitoring
Assessing severity of heart disease
Identification of systemic hypertension
Assessing response to drugs (eg vasodilators)

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85
Q

How do we measure blood pressure?

A
Direct method (more likely in anaesthetised patients)
Indirect methods (Doppler, oscillometric technique)
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86
Q

What is meant by systemic hypertension?

A

Blood pressure above normal for the species/breed

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87
Q

What is the normal blood pressure range for dogs?

A

(S/D) 133/75 mmHg

Sight hounds have higher blood pressure than other breeds (150/87 mmHg)

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88
Q

What is the normal blood pressure range for cats?

A

(S/D) 125/80 mmHg

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89
Q

What are the definitions of systemic hypertension for systolic and diastolic pressure?

A

Systolic: >160/175/180 mmHg
Diastolic: >95-100 mmHg
(eg 175/100 mmHg)

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90
Q

Give some disease associated with secondary systemic hypertension?

A
Chronic renal disease
Hyperthyroidism (cats)
Hyperadrenocorticism 
Diabetes mellitus
Liver diseases
Hypothyroidism
Acromegaly (excess GH)
Obesity
CNS disease
Chronic anaemia (cats)
Phaeochromocytoma (adrenal gland tumour)
Hyperaldosteronism
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91
Q

Give some consequences of systemic hypertension

A

Ocular (retinal haemorrhage, hyphaema-pooled blood in anterior chamber of eye, retinal detachment, blindness)
CNS (seizures, dull and depressed, bad-tempered)
Renal (failure, proteinuria etc)
Cardiac (pressure overload -> concentric left ventricular hypertrophy, heart murmurs)

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92
Q

What is the difference between eccentric and concentric ventricular hypertrophy?

A

Eccentric: volume overload. Wall thickness increases in proportion to the increase in chamber radius

Concentric: chronic pressure overload. Wall thickness increases but the chamber radius may not change, ventricle becomes stiff

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93
Q

What should you do after diagnosing systemic hypertension?

A

Check for end-organ damage (examine retinas, history and neuro exam, check urine SG and protein:creatinine ratio, ECG)
Search for an underlying cause as primary hypertension is rare in cats and dogs

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94
Q

Which drug can you use to treat systemic hypertension?

What doses would you use for dogs and cats?

A

Amlodipine (calcium channel antagonist with only vascular effects)
Cats: start at 1/4 of 5mg tablet, SID
Dogs: start at 0.05-0.1mg/kg SID or BID
Check BP after 1 week, increase dose if required

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95
Q

When treating systemic hypertension, what can you use as well as Amlodipine to protect the kidneys?

A

Ace inhibitors

reduce glomerular capillary pressure

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96
Q

What is the difference between a thrombus and embolus?

A
Thrombus= initial clot
Embolus= clot which breaks off and travels down blood vessels
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97
Q

Why may a blood clot form?

A

Circulatory stasis
Hypercoagulable state
Endothelial injury
(Known as Virchow’s triad)

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98
Q

Where do feline arterial thrombus’ usually form?

A

Left atrium

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99
Q

What is FATE in cats?

Describe the physiology

A

Feline arterial thrombo-embolism
Thrombus forms, usually in left atrium, due to stasis of flow within the heart (any feline cardiomyopathy)
Embolisms may be to any region-often distal aorta (aortic trifurcation)
Severe clinical signs, pain etc
Emergency presentation

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100
Q

What is the major clinical sign of a cat presenting with FATE?

A

Loss of use of HLs

Marked pain, pale nail beds

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101
Q

What would be your first priority when seeing a cat with FATE?

A

Adequate analgesia

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102
Q

How do you treat FATE?

A

Priority: adequate analgesia and anxiolytic eg methadone, aspirin
Consider ‘clot busting’ drugs eg tissue plasminogen activator (tPA) if <6-12 hours of event
Stabilise underlying heart failure if present
Inhibit further platelet aggregation and activation eg aspirin, heparin
Prevent collateral vasoconstriction caused by thromboxane, serotonin etc (aspirin)
Grave prognosis, 50% survival rate

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103
Q

How can you prevent FATE in at-risk cats?

A

Low-dose aspirin (1/4 of 75mg aspirin every 3 days)
Clopidogrel (anti-platelet; inhibits blood clots) (better than aspirin)
Low molecular weight heparin
Treat cardiac disease as appropriate

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104
Q

Which dog breed may be pre-disposed to arterial thrombo-embolism?

A

Cavaliers

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105
Q

What is canine arterial thrombo-embolism associated with?

A

Rarely heart disease

More commonly associated with an endocrinopathy eg cushings, hypothyroidism

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106
Q

How would you identify canine thrombo-embolism?

A

Dogs present with HL weakness or pain, worse with exercise, sometimes only single limb
Pale/pulseless/cold compared with non-affected limb

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107
Q

Give some causes of pulmonary hypertension

A
Pulmonary vascular changes (eg retained foetal vasculature) -> pulmonary hypertension -> right to left shunting across congenital heart defects
Heart worm
Pulmonary thromboembolism
Left-sided heart failure
Primary severe respiratory conditions
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108
Q

How can you diagnose pulmonary hypertension?

A

Clinical exam: loud S2, loud TR murmur (tricuspid regurgitation)
Radiographs: dilated, tortuous or pruned pulmonary arteries
Doppler echo: dilated and hypertrophic RV, dilated pulmonary trunk, high velocity TR, PR jets

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109
Q

How do you treat pulmonary hypertension?

A

Treat underlying disease
Pimobendan?
Sildenafil (Viagra)

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110
Q

How do you diagnose pulmonary thrombo-embolism in dogs?

A

Arterial blood gas analysis: large alveolar to arterial gradient (A-a) showing significant ventilation:perfusion mismatch
Identify clot breakdown products: FDPs, D-dimers

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111
Q

Give some clinical signs of heartworm

A

Weight loss, fatigue, cough, dyspnoea

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112
Q

Which side of the heart are canine heartworms found?

A

Right

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113
Q

How do you diagnose canine heartworm?

A

Direct smear
Microfilaria concentration tests eg Modified Knott’s test
Heartworm antigen tests (only detects females)
Antibody test

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114
Q

Which drugs will prevent canine heartworm?

A

Selamectin (Stronghold), monthly topical
Milbemycin (Milbemax) (with praziquantel), po monthly
Moxidectin (Advocate) (with imidacloprid), monthly topical

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115
Q

What are Wolbachia?

A

Obligate, intracellular, gram negative, endo-symbiotic bacteria
Found in uterus of female Dirofilaria immitis
Treat with doxycycline prior to melarsamine

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116
Q

What adulticide would you use to treat Dirofilaria?

A

Melarsomine Dihydrochloride

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117
Q

What is angiostrongylus vasorum?

A

‘French heart worm’
Adults are 2cm long
Metastrongyle parasite of dogs and foxes
Slugs and snails=intermediate host

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118
Q

What are the clinical signs of angiostrongylus vasorum?

A
Often young dogs
May be asymptomatic
Chronic, unresponsive coughing 
Dyspnoea, haemoptysis (coughing up blood/bloody mucus)
Ill thrift, exercise intolerance, CHF
SC and retinal haemorrhages
Paresis, ocular changes
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119
Q

How do you diagnose angiostrongylosis?

A
Thoracic radiography (mixed pulmonary infiltrates)
Eosinophilia
Raised beta-globulins 
SNAP test (for antigen)
Larvae in faeces (Baermanns)
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120
Q

How do you treat angiostrongylosis?

A

Fenbendazole (slowly kills over 36 hours)
Milbemycin oxime (with praziquantel)
Moxidectin (with imidacloprid)
Prednisolone if severe pulmonary changes

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121
Q

How can you prevent angiostrongylus?

A

Moxidectin or Milbemycin every 4 weeks

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122
Q

Describe MDVD

A
Acquired condition (happens over time)
Small breeds; middle-aged/older dogs
Most common cardiac disease
Idiopathic
Nodular thickening -> leakage 
Cardiac valve leaflets
Proteoglycan accumulation
Cavalier King Charles Spaniel
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123
Q

Give some other names for MDVD

A
Myxomatous degenerative valvular disease
Degenerative valvular heart disease
Mitral endocadiosis
Chronic valvular insufficiency 
Suspected genetic basis
Lengthened/ruptured chordae
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124
Q

Give the macroscopical pathology of MVDV

A

Left atrium dilation
Left ventricle dilation
Elongation and thickening of chordae tendinae, which may rupture
Thickened leaflets
Jet lesions may be seen in atrial endocardium

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125
Q

Describe the microscopic pathology of MDVD

A

Accumulation of glycosaminoglycans within the valve leaflets with disrupted collagen matrix

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126
Q

What is the difference between eccentric and concentric hypertrophy?

A

Eccentric: walls stay at an appropriate thickness (no change in chamber volume)
Concentric: increase in wall thickness and reduced chamber volume

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127
Q

Define MDVD

A

Nodular thickening of the cardiac valve leaflets associated with proteoglycan accumulation.
The atrioventricular valves (especially mitral valve) are most commonly affected, with the aortic valves being affected to a lesser extent

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128
Q

Which kind of hypertrophy is seen with MDVD and why?

A

Eccentric: dilated left atrium and ventricle due to chronic volume overload

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129
Q

Describe the likely presentation of a dog with MDVD

A
Adult dogs
Small breeds
Heart murmur-may be asymptomatic
Cough
Breathing changes
Exercise intolerance
May progress to right-sided congestive heart failure
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130
Q

Why is a chronic cough often the first clinical sign of MDVD?

A

Marked left atrial enlargement -> compression of the caudal mainstem bronchi `

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131
Q

How does pulmonary oedema occur with MDVD?

A

The increased filling pressures within the left atrium lead to backpressure in the pulmonary vasculature -> increased hydrostatic pressure and pulmonary oedema

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132
Q

When doing a physical exam on a dog with MDVD, what would you hear when auscultating the lungs?

A

Increased respiratory sounds
Crackles
Tachypnoea/dyspnoea
(Pulmonary oedema)

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133
Q

Give some signs of right-sided congestive heart failure

A

Hepatojugular reflex (squeeze abdomen at liver, does jugular pop out?)
Jugular distension
Abdominal effusion
Hepatomegaly

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134
Q

Where is the point of maximal intensity of a heart murmur in a dog with MDVD?

A

Over left apex (mitral regurgitation)

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135
Q

What 3 arrhythmias may be seen with MDVD?

A

Supraventricular premature complexes
Atrial fibrillation
Ventricular premature complexes

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136
Q

On an ECG, what does a prolonged P wave represent?

A

Left atrial enlargement

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137
Q

On an ECG, what does a tall R wave represent?

A

Left ventricular enlargement

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138
Q

On an ECG, what does a prolonged QRS represent?

A

Conduction disturbance

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139
Q

What value should a dog’s vertebral heart scale be?

A

> 10.5

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140
Q

What might you see on a radiograph in a dog with MDVD?

A

Cardiomegaly (check vertebral heart scale)
Left atrial enlargement
Lung patterns
-Prominent lobar vessels -> early pulmonary congestion
-Interstitial lung pattern -> early pulmonary oedema
-Alveolar pattern -> pulmonary oedema

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141
Q

What is the best diagnostic method for confirming MDVD?

A

Echocardiography

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142
Q

What would you see on an echocardiography of a dog with MDVD?

A

Thickened atrioventricular leaflets (may see ruptured chordae tendinae)
Enlarged left atrium (LA>LV)
Dilated, rounded left ventricle
Hyperdynamic systolic function (reduced afterload, increased preload)
Mitral regurgitation
Pulmonary hypertension

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143
Q

What other pathology may dogs with CHF have?

A

Pre-renal azotaemia

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144
Q

What is NT-proBNP?

A

Marker for heart failure

Released by atrial/ventricular stretch

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145
Q

What is Troponin I?

A

Marker of myocardial cell damage (part of sarcomere of myocyte)

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146
Q

Give a good treatment plan for CHF

A

Furosemide (diuretic, essential in CHF)
Spironolactone (weak diuretic, anti-remodelling effects)
ACE-inhibitors (vasodilators, reduce afterload)
Pimobendan (positive inotrope and vasodilator, addreses pulmonary hypertension)

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147
Q

Which drugs could you give to treat a supraventricular arrhythmia associated with MDVD?

A

-Diltiazem (calcium channel blocker)
-Digoxin

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148
Q

What is the estimated life span of a dog once is develops CHF?

A

12 months

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149
Q

What is endocarditis?

A

Infection of one or more endocardial valves

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150
Q

Give some infectious agents that cause endocarditis

A
Streptococcus spp
Staphylococcus spp
E.coli
Pseudomonas
Bartonella spp etc
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151
Q

Endocarditis is more likely to occur on which valves?

A

Aortic or mitral

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152
Q

What would you suspect in a case of pyrexia of unknown origin and a new heart murmur?

A

Endocarditis

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153
Q

What conditions are required for endocarditis to occur?

A

Bacteraemia (eg infections, IV catheter, surgery)
Damaged endothelium (turbulence, high velocities)
Bacteria must be able to adhere and evade host defences
Hypercoagulable states

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154
Q

Describe the pathology of endocarditis

A

Vegetations on endocardial surface of valve leaflets (ie atrial/ventricular surfaces)
Affected valves usually deformed; can be perforated, haemorrhagic, calcified if mature
Microscopic findings:
-Platelets, WBCs, RBCs, bacteria, fibrin
-Fibrous tissue, calcification in mature lesions
Septic/sterile arterial embolisation (kidney, heart, lung, brain)

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155
Q

Describe the pathophysiology of endcarditis

A

Persistent/intermittent bacteraemia -> systemic inflammatory response
Thromboembolic events (septic)
-Organ infarction
-Abscess formation
-Neurological signs
-Shifting lameness
Stimulation of humoral/cellular Immune system: Immune complex, antinuclear antibodies
-Clotting abnormalities -> DIC
-Proteinuria -> glomerulonephritis
-Polyarthritis, glomerulonephritis, myocarditis
Valvular regurgitation (mitral/aortic) leading to volume overload. Also stenosis leading to pressure overload of left ventricle.
-Increased myocardial workload
-Congestive heart failure

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156
Q

How would you diagnose endocarditis?

A

Blood culture

  • At least 3 puncture sites, 10ml per sample
  • Prior to antibiosis

Echocardiography

  • Presence of valvular vegetations
  • Regurgitation from affected valve

ECG
-May show tachycardia or arrhythmias

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157
Q

What clinical pathology would you see with endocarditis?

A

Usually neutrophilia +/- left shift
Commonly thrombocytopenia -> DIC?
Abnormalities associated with thromboembolic disease

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158
Q

How could you diagnose endocarditis using modified Duke’s criteria?

A

Must have 2 major criteria/ 5 minor/ 1 major and 3 minor criteria

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159
Q

Give the major criteria of the modified Duke’s criteria, used for diagnosing endocarditis

A

Positive echocargiogram
New valvular insufficiency
Positive blood culture

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160
Q

Give the minor criteria of the modified Duke’s criteria, used for diagnosing endocarditis

A
Fever
Medium/large breed
Subaortic stenosis
Thromboembolic disease
Immune-mediated disease
Positive blood culture not meeting major criteria
Bartonella serology ≥1:1024
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161
Q

How do you treat endocarditis?

A

Bactericidal antibiotics based on culture and sensitivity (fluoroquinalone and potentiated amoxicilin + metronidazole whilst awaiting culture)
Minimum 6 weeks
Anti-coagulation
Monitoring of acute-phase proteins

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162
Q

What is the prognosis like for endocarditis?

A

Guarded-poor

  • Recurrence
  • Complications
  • Irreversible valve damage -> volume overload and congestive heart failure
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163
Q

What is the msot common primary cardiomyopathy in dogs?

A

Dilated cardiomyopathy

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164
Q

What is ARVC?

Which breed is more affected?

A

Arrhythmic right ventricular cardiomyopathy

Boxers

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165
Q

Give some primary cardiomyopathies in dogs

A
  • Dilated cardiomyopathy
  • Arrhythmic right ventricular cardiomyopathy
  • Hypertrophic cardiomyopathy
  • Atrial cardiomyopathy
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166
Q

Which dog breeds are more prone to hypertrophic cardiomyopathy?

A

Terrier breeds, pointers, golden retriever

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167
Q

Which dog breeds are more prone to atrial cardiomyopathy?

A

Labrador, english springer spaniel

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168
Q

How would you recognise atrial standstill on an ECG?

A

No p waves

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169
Q

What can cause primary myocarditis?

A

Viruses (eg Parvo) and autoimmune response

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170
Q

What can cause secondary myocarditis?

A

Inflammation, specific pathogens (eg distemper virus, Toxoplasma, Leptospira spp. and Leishmania)

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171
Q

What happens to the heart with dilated cardiomyopathy?

A
  • Impaired systolic function (ie reduced contractility; cell death and fatty/fibrous replacement)
  • Dilated cardiac chambers
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172
Q

What causes dilated cardiomyopathy?

A

Idiopathic

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173
Q

What kind of dogs are affected by dilated cardiomyopathy?

A
  • Adult onset

- Medium-large breeds (eg Doberman)

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174
Q

What can happen as a result of dilated cardiomyopathy?

A
  • CHF

- Sudden death

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175
Q

Left ventricular hypertrophy in dogs is most likely to occur secondary to which conditions?

A
  • Aortic stenosis
  • Systemic hypertension
  • Infiltrative disease
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176
Q

Why may atrial cardiomyopathy ultimately result in a pacemaker?

A

-Atrial wall thinning -> atrial standstill

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177
Q

Give some examples of drugs which can cause secondary cardiomyopathies

A
  • Chemotherapy drugs eg doxorubicin/epirubicin, cyclophosphamide
  • Heavy metals
178
Q

Give some infiltrative conditions that can cause secondary cardiomyopathies

A
  • Neoplasia

- Glycogen storage diseases, amyloidosis

179
Q

What is the most commonly recognised nutritional cardiomyopathy?
Which breeds does it affect?

A
  • Taurine deficiency

- Cocker Spaniels, Golden Retrievers and some Newfoundlands

180
Q

Describe the pathology of dilated cardiomyopathy

A

-Dilation of any of the 4 cardiac chambers
-Increased heart weight:body weight ratio
-Thin, stretched walls
-Valvular lesions: age related, due to mitral regurgitation
caused by valvular annulus stretching
-LV thickness: LV diameter is reduced

181
Q

What histological patterns are seen with dilated cardiomyopathy?

A
  • Attenuated wavy fibres (atrophied) (thin myocytes)
  • Fibro-fatty degeneration (vacuolation, myocyte lysis)
  • ie cell death and fibrous or fatty replacement
182
Q

How does the heart maintain blood pressure with dilated cardiomyopathy?

A
  • Activates sympathetic nervous system (tachycardia, vasoconstriction)
  • RAAS (retention of Na and fluid, increased circulatory volume, vasoconstriction)
  • Remodelling-myocardial eccentric hypertrophy (improved systolic function)
183
Q

How does dilated cardiomyopathy lead to mitral regurgitation?

A
  • Activation of sympathetic nervous system -> intracellular Ca overload, increased O2 demand -> cell death
  • Remodelling of myocardial eccentric hypertrophy -> fibrosis, increased wall stress, dilation of valvular annulus -> mitral regurgitation
184
Q

Give some similarities between mitral degenerative valve disease and dilated cardiomyopathy

A
  • Enlarged left ventricle (+/- right)
  • Enlarged left atrium
  • Mitral regurgitation
185
Q

Give some differences between mitral degenerative valve disease and dilated cardiomyopathy

A

MDVD:

  • Lots of mitral regurgitation
  • Normal systolic function (contractility)
  • Left atrium bigger than left ventricle

DCM:

  • Mild mitral regurgitation
  • Reduced systolic function (contractility)
  • Left ventricle bigger than left atrium
186
Q

How do dilated cardiomyopathies in dalmations differ from other breeds?

A
  • May see ventricular premature complexes on ECG

- May be associated with nutrition (low protein diet)

187
Q

How do dilated cardiomyopathies in cocker spaniels differ from other breeds?

A
  • May be due to taurine deficiency

- Slow progression over many years

188
Q

How do dilated cardiomyopathies in irish wolfhounds differ from other breeds?

A

-Can present with lone atrial fibrillation -> progression to overt DMC?

189
Q

How do dilated cardiomyopathies in dobermans differ from other breeds?

A
  • Long asymptomatic preclinical phase (2-4 yrs)
  • Sudden death
  • Ventricular arrhythmias
  • Short survival after developing CHF (2-4 months)
190
Q

What is arrhythmogenic right ventricular cardiomyopathy?

A
  • Loss of myocytes with fatty/fibrofatty replacement, resulting in regional or global abnormalities
  • Right ventricle
191
Q

Arrhythmogenic right ventricular cardiomyopathy is seen mostly in which dog breed?

A

Boxer

192
Q

What are the 3 types of arrhythmogenic right ventricular cardiomyopathy?

A
  • Asymptomatic- VPCs detected by Holter monitoring
  • Symptomatic (syncopal)- arrhythmias, normal systolic function
  • DCM + arrhythmias
193
Q

What is the most likely cause of arrhythmogenic right ventricular cardiomyopathy?

A

Genetic

194
Q

What are the clinical signs of heart disease?

A
  • Cough
  • Tachypnoea/dyspnoea
  • Exercise intolerance
  • Abdominal distension (ascites/hepatomegaly)
  • Synope
  • Collapse?
  • Increased water intake?
  • Heart murmur
  • Sudden death?
  • No signs
195
Q

Describe the pahtology of arrhythmogenic right ventricular cardiomyopathy

A
  • Fibrofatty tissue replacement particularly in the right ventricle, but also the LV and often the atria
  • Fatty tissue or scarring may be seen grossly
  • Possibly dilated heart
196
Q

Describe a likely clinical presentation of a dog with dilated cardiomyopathy

A
  • Large breeds, adults
  • Exercise intolerance
  • Most dogs are in CHF at presentation (or can be asymptomatic)
197
Q

Describe a likely clinical presentation of a dog with mitral degenerative valve disease

A
  • Small breeds. adults

- Loud heart murmur

198
Q

Where would you hear mitral regurgitation when auscultating the heart?

A

Left apex, 5th IC space

199
Q

What might you find on a clinical exam of a dog with dilated cardiomyopathy?

A
  • Cardiac cachexia (muscle wasting)
  • Mm: pale, sluggish CRT
  • Tachypnoea, dyspnoea
  • Weak femoral pulses
  • Pulmonary oedema
  • Jugular distension, abdominal effusion, positive hepatojugular reflex (R-CHF)
  • Cough
200
Q

How would you identify pulmonary oedema on auscultation?

A
  • Crackles
  • Increased respiratory sounds
  • Tachypnoea/dyspnoea
201
Q

What kind of murmur may you hear with dilated cardiomyopathy?

A

Soft systolic murmur left apex, grade 1-4

202
Q

What kind of murmur may you hear with mitral degenerative valve disease?

A

Soft systolic murmur left apex, grade 2-4

203
Q

Which diagnostic tests can you do to diagnose dilated cardiomyopathy?

A
  • Blood pressure
  • ECG
  • Thoracic radiographs
  • Echocardiography
204
Q

Which common arrhythmias may be seen with mitral degenerative valve diease?

A
  • Supraventricular premature complexes
  • Atrial fibrillation
  • Ventricular premature complexes
205
Q

Which common arrhythmias may be seen with dilated cardiomyopathy?

A
  • Atrial fibrillation
  • Ventricular premature complexes
  • Supraventricular premature complexes
  • Ventricular tachycardia
206
Q

What would you see on an echocardiography of a dog with dilated cardiomyopathy?

A

-Enlarged left atrium
-Dilated, rounded left ventricle
-LV>LA
-Thin walls?
-Reduced systolic function
-Mild mitral regurgitation
Asynchronous contraction of LV walls

207
Q

What would you see on an echocardiography of a dog with mitral degenerative valve disease?

A
-Enlarged left atrium
Dilated, rounded left ventricle
-LA>LV
-Thin walls?
-Hyperdynamic systolic function
-Lots of mitral regurgitation
208
Q

What other clinical pathology findings may be present with dilated cardiomyopathy?

A
  • Pre-renal azotaemia (reduced CO -> reduced renal perfusion)
  • Mild increases of liver enzymes due to liver congestion
  • Low albumin if effusions
  • Rule out hypothyroidism
209
Q

Give some metabolic/endocrine causes of secondary cardiomyopathies

A
  • Hypothyroidism
  • Hyperthyroidism (rare, iatrogenic)
  • Systemic hypertension
  • Diabetes mellitus
  • Acromegaly (rare in cats, even rarer in dog)
210
Q

What is Troponin-1?

A

Marker for myocardial cell damage (not specific for cardiac disease)

211
Q

What is NT-proBNP?

A
  • Marker for heart stretch
  • May help identify failure
  • Helps to assess severity of disease
212
Q

Why might you carry out Ambulatory ECG-Holter monitoring?

A

-Permits diagnosis of DCM in preclinical/occult phase
(ie arrhythmias without chamber dilation and/or systolic dysfunction)
-Assessment of arrhythmias
-Assessment of response to treatment

213
Q

What are the main principles for treating dilated cardiomyopathy?

A
  • Inotropic support (positive inotrope -> increase contractility)
  • Reduce preload
  • Reduce afterload
  • Control arrhythmias
  • Nutraceuticals
214
Q

How can you reduce preload in a dog with dilated cardiomyopathy?

A

Venodilators and diurectics:

  • Furosemide (essential in CHF)
  • Torasemide
  • Spironolactone (anti-remodelling effects)
  • Thiazide (if furosemide resistance)
  • Glyceryl trinitrate (percutaneous venodilator, acute pulmonary oedema)
215
Q

How can you provide inotropic support to a dog with dilated cardiomyopathy?

A
  • Pimobendan (positive inotrope and vasodilator)

- Dobutamine (sympathomimetic, use in emergency situations eg no response to heart failure meds)

216
Q

How can you reduce afterload in a dog with dilated cardiomyopathy?

A

Vasodilators:

  • ACE inhibitors eg benazepril
  • Pimobendan
217
Q

Which drugs can you give to dogs in the preclinical stage of dilated cardiomyopathy?

A
  • Pimobendan
  • ACE inhibitors (eg benazepril)
  • Prolong onset of CHF
218
Q

How can you control atrial fibrillation in dogs with dilated cardiomyopathy?

A
  • Diltiazem
  • Digoxin
  • Beta blockers (don’t use in heart failure!)
219
Q

How can you control ventricular arrhythmias in dogs with dilated cardiomyopathy?

A
  • Lidocaine (emergency tx)
  • Sotalol
  • Amiodarone
220
Q

Which neutraceuticals can you use when treating dilated cardiomyopathy?

A
  • Omega 3 Fatty acids (for cardiac cachexia, antiarrhythmic in Boxers)
  • L-carnitine, taurine
  • Na+ restricted diets
221
Q

What should you measure when treating atrial fibrillation with Digoxin?

A

-Check K+ levels (check serum levels 5-7 days post-tx, 6-8 hours post-pill)

222
Q

What is the general prognosis for dilated cardiomyopathy?

A

-Guarded to poor (6-12 months)

223
Q

Give some primary myocardial diseases in cats

A
  • Hypertrophic cardiomyopathy (HCM) or Hypertrophic
    (obstructive) cardiomyopathy (HOCM)
  • Restrictive cardiomyopathy (RCM)
  • Unclassified cardiomyopathy (UCM)
  • Dilated cardiomyopathy (DCM)
  • Arrhythmogenic right ventricular cardiomyopathy (ARVC)
224
Q

Give some secondary myocardial diseases in cats

A
  • Hypertensive cardiomyopathy
  • Hyperthyroid cardiomyopathy
  • Cardiomyopathy associated with other systemic disease e.g. renal failure, acromegaly (normally associated with insulin resistant diabetes mellitus) etc.
225
Q

How would you characterise feline hypertrophic cardiomyopathy?

A
  • Marked concentric hypertrophy of left ventricle
  • Diastolic dysfunction (difficulty filling the ventricles)
  • Increased HR
  • Increased O2 usage, possible O2 starvation of heart muscle -> cells can die off -> arrhythmias
  • Can result in CHF/blood clots in heart
226
Q

When diagnosing feline hypertrophic cardiomyopathy, which other potential causes of concentric hypertrophy must you rule out?

A
  • Aortic stenosis
  • Systemic hypertension
  • Hyperthyroidism
  • Chronic renal failure
  • Acromegaly (+/- diabetes mellitus)
227
Q

What are the causes of feline hypertrophic cardiomyopathy?

A
  • Idiopathic
  • Genetic in some breeds (eg persian, ragdoll)
  • Maine coon and ragdoll: mutations detected in myosin binding protein C (genetic tests available)
228
Q

How do you diagnose feline hypertrophic cardiomyopathy?

A

Echocardiography
-Demonstration of concentric hypertrophy (with
wall measurements ≥ 6 mm in diastole)
-Hypertrophy is usually symmetrical, but can be focal

229
Q

What is a ‘valentine heart’ on a thoracic radiograph?

A

-Biatrial enlargement (not specific for a particular myocardial disease, but used to diagnose hypertrophic cardiomyopathy in advanced disease)

230
Q

What is the best method for seeing whether a cat is in left-sided congestive heart failure?

A

Radiography to look for pulmonary oedema

231
Q

What 3 things seen together on a thoracic radigraph indicate pulmonary oedema?

A
  • Left atrial enlargement
  • Pulmonay venous distension
  • Pulmonary infiltrate
232
Q

Describe the source of heart murmurs in hypertrophic cardiomyopathy

A
  • Septal bulge results in left ventricular outflow tract (LVOT) obstruction
  • This may also cause the anterior mitral valves leaflet to be ‘sucked’ into the left ventricular outflow tract = systolic anterior motion (SAM)
  • This leaves the mitral valve incompetent -> mitral regurgitation
233
Q

What is a diastolic gallop?

A

The detection of S3 and S4 heart sounds

234
Q

What is S3?

A
  • Rapid deceleration of blood in left ventricle

- Detected if the LV is stiff or has increased pressure

235
Q

What is S4?

A

-Left ventricular filling, associated with atrial contraction -Detected if there is increased dependence on atrial contraction, such as slow relaxation (as in HCM)

236
Q

What are the clinical signs of hypertrophic (obstructive) cardiomyopathy?

A
  • May be asymptomatic, only detected due to presence of heart murmur
  • L-CHF (may have acute presentation with pulmonary oedema or thromboembolism)
237
Q

Describe feline aortic thromboembolism (FATE)

A

-Stasis of blood flow in the dilated left atrium may result in thrombus formation -> thrombo-embolism to the distal aorta -> ischaemic neuromyopathy (HL paralysis)

238
Q

How do you treat hypertrophic (obstructive) cardiomyopathy?

A
  • Diuretics (furosemide)
  • Drain a pleural effusion causing dyspnoea
  • ACE inhibitors (once CHF is present, none licensed but use benazepril as licensed for renal insufficiency)
  • Prevent thromboembolism (eg aspririn, clopidogrel)
239
Q

What treatment can you use in an asymptomatic cat with hypertrophic (obstructive) cardiomyopathy?

A
  • Beta blockers (eg atenolol) reduce severity of LVOT and SAM, slow HR (and thus improve diastolic function), reduce wall stress and stimulus to further concentric hypertrophy
  • Diltiazem : positive lusiotrope (improves relaxation)
  • ACE inhibitors
  • All 3 classes cause a decrease in wall thickness
240
Q

When should beta blockers never be used?

A

In cats with uncontrolled CHF

241
Q

What is clopidogrel?

A
  • Anti-platelet drug

- Used to prevent thromboembolism in HCM

242
Q

What causes dilated cardiomyopathy in cats?

A
  • Rare
  • Taurine deficiency
  • Genetics- Abyssinian/Somali cats
243
Q

How do you diagnose dilated cardiomyopathy in cats?

A

Echocardiography (dilated, hypokinetic left ventricle with thin walls)

244
Q

How do you treat dilated cardiomyopathy in cats?

A
  • Pimobendan (positive inotrope)
  • Supplement taurine
  • Drain any pleural effusions
  • Humidified O2
  • Furosemide (diuretic)
  • ACE inhibitors
245
Q

What are the 2 forms of restrictve cardiomyopathy?

A
  • Myocardial

- Endomyocardial

246
Q

How would you characterise restrictive cardiomyopathy?

A
  • Enlarged left atrium (may see ‘smoke’)
  • Normal left ventricle
  • Significant diastolic dysfunction
247
Q

How do you treat restrictive cardiomyopathy?

A
  • Furosemide and ACE inhibitors
  • Pimobendan is indicated in the presence of impaired systolic function
  • Thromboembolism-prevention meds (clopidogrel?)
248
Q

What is an unclassified cardiomyopathy?

A

-Features of more than one form of cardiomyopathy

249
Q

Arrhythmogenic right ventricular cardiomyopathy (ARVC) usually affects which kinds of cats?

A
  • Older cats >10yrs old

- Birmans

250
Q

What happens to the heart with arrhythmogenic right ventricular cardiomyopathy (ARVC)?

A

-Right ventricular myocardium becomes replaced with a fibro-fatty infiltrate

251
Q

Give some clinical signs of arrhythmogenic right ventricular cardiomyopathy (ARVC) in cats

A
  • R-CHF
  • Ventricular arrhythmias
  • Conduction disturbances
  • May have pleural effusions, ascites
252
Q

How do you treat arrhythmogenic right ventricular cardiomyopathy (ARVC) in cats?

A

Furosemide and ACE-inhibitors

253
Q

How would you treat dyspnoea in a cat due to pulmonary oedema?

A
  • Do not stress!
  • Sedate (methadone or buprenorphine)
  • Provide humidified O2
  • Give furosemide iv e.g. 1 mg/kg every 1-2 hours
  • Apply nitroglycerine topically to medial pinna (venodilator, reduces pulmonary oedema)
  • Furosemide and ACE inhibitors orally long-term. Pimobendan if poor systolic function.
254
Q

Describe the layers of the pericardium

A

-Outer: fibrous pericardium: tough sac that continues with the adventitia of the great vessels dorsally, and with the sternopericardial ligament ventrally
-Inner: serous pericardium: contains two layers withpericardial fluid between them. A thin
layer of mesothelial cells is present in the inner aspect of the layers.
-Parietal layer: forms the inner surface of the fibrous pericardium
-Visceral layer: forms the epicardium

255
Q

Where does the main innervation of the pericardium come from?

A
  • Vagus nerve (X)
  • Laryngeal recurrent nerve (XI)
  • Sympathetic nerve fibres
  • Phrenic nerves course over lateral surfaces of pericardium (pericardial pain)
256
Q

Where does the blood supply to the pericardium come from?

A
  • Aorta
  • Internal thoracic artery
  • Musculophrenic arteries
257
Q

Which lymph nodes drain the pericardium?

A

Cardiac, mediastinal and pre-sternal lymph nodes

258
Q

How much fluid does the pericardium contain?

What is its function?

A
  • 0.25ml/kg

- Acts as a lubricant

259
Q

Give some functions of the pericardium

A
  • Prevents over-dilation
  • Protects heart from infection
  • Systolic function
  • Maintains the heart in a fixed position within the thorax
  • Co-ordinates function between LV and RV
260
Q

Pericardial disease in cats is usually associated with what?

A

Cardiomyopathy or as an incidental manifestation of systemic disease

261
Q

How can we classify pericardial disease?

A

Congenital or acquired

262
Q

What is PPDH?

A

Peritoneopericardial diaphragmatic hernia

263
Q

Give some congenital causes of pericardial disease

A
  • Peritoneopericardial diaphragmatic hernia
  • Intra pericardial cyst
  • Pericardial defect/absence
264
Q

Give some acquired causes of pericardial disease

A
  • Pericardial effusion (eg haemorrhagic, transudtae, exudate)
  • Constrictive/effusive-constrictive pericarditis
265
Q

Describe peritoneopericardial diaphragmatic hernia (PPDH)

A
  • Defect in ventral diaphragm and pericardium -> abdominal organs within pericardial sac
  • Commonly additional sternal malformations, ventral abdominal hernias and congenital heart diseases
266
Q

Which breeds are more prone to peritoneopericardial diaphragmatic hernias?

A
  • Weirmaraners

- Persian cats

267
Q

Give some clinical signs of peritoneopericardial diaphragmatic hernias

A
  • May be asymptomatic
  • May have respiratory or GI signs (depending on herniated organs)
  • Apex beat may be absent/ displaced, muffled heart sounds
268
Q

How do you diagnose peritoneopericardial diaphragmatic hernias?

A

Radiography, echocardiography

269
Q

How do you treat peritoneopericardial diaphragmatic hernias?

A

Surgery

270
Q

What are the most common causes of pericardial effusion?

A
  • Idiopathic

- Neoplasia

271
Q

Which kinds of dogs are affected by pericardial effusion?

A

Older, large breed dogs

272
Q

Which kinds of cats are affected by pericardial effusion?

A

Cats with CHF and systemic disease (eg FIP)

273
Q

Give some other, less common causes of pericardial effusion

A

Lymphoma, rhabdomyosarcoma, bacterial pericarditis (after dog bite, trauma), coccidiomycosis, aspergillus, coagulation disorder, uraemia

274
Q

How could you treat an idiopathic pericardial effusion?

A

Pericardiectomy if it recurs for 3rd time (also allows for pericardial biopsy and exploratory thoracotomy)

275
Q

Which neoplasia types can cause neopalstic pericardial effusion?

A
  • Haemangiosarcoma
  • Chemodectoma/aortic body tumour (heart base tumour)
  • Mesothelioma
  • Others eg lymphoma
276
Q

Which dog breeds are more prone to haemangiosarcomas causing neoplastic pericardial effusion?

A
  • GSD
  • Golden Retriever
  • Setters
277
Q

Describe a haemangiosarcoma causing neoplastic pericardial effusion

A
  • Right atrium/right auricular appendage
  • Commonly spleen +/- liver also affected
  • Quick recurrence of effusion after pericariocentesis
  • Grave prognosis (MST=6 months)
278
Q

How can you treat a haemangiosarcoma causing neoplastic pericardial effusion?

A
  • Palliative: pericardiocentesis, pericardiectomy, balloon pericardiotomy
  • Chemotherapy +/- surgery
279
Q

Which dog breeds are more prone to chemodectomas causing neoplastic pericardial effusion?

A

-Brachycephalics (older dogs)

280
Q

Describe a chemodectoma

A
  • Benign, slow-growing tumour at the heart base

- Locally invasive but low metastatic rate

281
Q

How do you treat a chemodectoma?

A

-Palliative pericardiectomy

Can’t surgically remove

282
Q

How do you treat a mesothelioma of the pericardium?

A
  • Difficult to treat

- Intracavitary cisplatin, IV doxorubicin

283
Q

Describe the pathophysiology of pericardial effusion

A

Accumulation of fluid within the pericardial sac impedes ventricular filling of the heart during diastole

284
Q

Describe the pathophysiology of chronic pericardial effusion

A
  • Decreases stroke volume -> activates RAAS and sympathetic system -> peripheral vasoconstriction, increased heart rate and fluid retention
  • Cardiac tamponade: collapse of RA (sometimes RV) during diastole (due to elevated intrapericardial pressures)
  • Venous return to the heart is compromised -> R-CHF
  • Pulsus paradoxus (no/reduced pulse during inspiration)
285
Q

Give the clinical signs of pericardial disease

A

Non-specific:

  • Lethargy
  • Decreased appetite
  • Vomiting
  • Diarrhoea
  • Increased panting
  • Increased thirst

Specific signs:

  • Abdominal enlargement
  • Decreased exercise tolerance
  • Syncope/collapse
  • Respiratory distress
286
Q

How would you identify pericardial disease on a clinical exam?

A

Usually presents as R-CHF with muffled heart sounds and weak femoral pulses so may see:

  • Ascites (abdominal fluid wave)- ballotment
  • Jugular distension
  • Positive hepatojugular reflux
  • Hepatomegaly/splenomegaly
  • Muffled heart sounds ie apex beat
  • Weak femoral pulses- pulsus paradoxus (not always present)
  • Tachycardia
287
Q

How do you diagnose pericardial disease?

A
  • PCV
  • Haem, biochem (commonly find pre-renal azotaemia, increased liver enzymes, anaemia)
  • Blood pressure (can be hypotensive due to severe forward failure, haemorrhagic shock)
  • ECG
  • Radiography
  • Echocardiography
  • Abdominal US (to look for neoplasia/concurrent disease)
288
Q

What would you see on a radiograph of an animal with pericardial effusion?

A
  • Globoid enlarged cardiac silhouette
  • Dorsal deviation of trachea
  • Dilated caudal vena cava
  • Small pulmonary vessels
  • Abdominal effusion
  • Pericardial fluid analysis
289
Q

What would you see on an ECG of an animal with pericardial effusion?

A
  • Small complexes
  • Sinus tachycardia
  • Differences in height of QRS complexes due to movement of heart swinging in the fluid
290
Q

What would you see on an echocardiography of an animal with pericardial effusion?

A
  • Presence of hypoechoic (black) fluid around the heart
  • Hyperechoic (white) pericardial line surrounding the fluid
  • Collapse of the right atrium (tamponade)
  • Swinging of the heart within the fluid
  • Pleural effusion might also be present
291
Q

What should you do with pericardial fluid when investigating a pericardial effusion?

A

Send for cytology +/- culture

292
Q

What does pericardial fluid look like?

A
  • Sanguineous/serosangineous

- Dark red color

293
Q

What is cardiac tamponade?

A

Collapse of RA (sometimes RV) during diastole (due to elevated intrapericardial pressures)

294
Q

How do you treat a pericardial effusion?

A
  • NOT DIURETICS!
  • If tamponade is present, prompt pericardiocentesis is the only tx option
  • High-rate fluids can be given IV to increase cardiac pre-load
295
Q

What should you check before doing a pericardiocentesis?

A

PCV

296
Q

Why should you not use diuretics when treating pericardial effusion?

A

-Will further reduce the cardiac pre-load and worsen cardiac tamponade

297
Q

What hapens on an ECG following pericardiocentesis?

A

-QRS complexes usually become bigger and heart rate decreases after drainage, occasional VPCs towards the end of procedure

298
Q

Why should you check PCV of pericardial fluid when doing pericardiocentesis?

A

If PCV is same as patients own blood-STOP! Probably haemorrhagic effusion

299
Q

Where should you perform pericardiocentesis?

A

5th - 6th intercostal space

300
Q

Give some complications of performing pericardiocentesis

A
  • Pneumothorax (due to rapid increase in left heart filling)
  • Arrhythmias (usually self-limiting): atrial fibrillation (due to sudden expansion of atrias), ventricular arrhythmias
  • Coronary lacerations, intracardiac puncture, pneumothorax (rare)
301
Q

Describe the pericardium with costrictive/effusive-constrictive pericarditis

A

Thickened, fibrotic, non-distensible

302
Q

What may cause constrictive/effusive-constrictive pericarditis?

A

Idiopathic or secondary to:

  • Recurrent pericardial effusion
  • Neoplasia
  • Foreign body
  • Infectious pericarditis
303
Q

Give some clinical signs of constrictive/effusive-constrictive pericarditis

A

R-CHF and cardiac tamponade

304
Q

How do you treat constrictive/effusive-constrictive pericarditis?

A

Pericardectomy and surgical stripping of the fibrotic pericardium

305
Q

What is the prognosis for surgical stripping of the fibrotic pericardium?

A

Guarded-grave

306
Q

Which kinds of dogs can suffer from left atrial rupture/tears?

A

Small breeds with advanced mitral valve disease and severe LA enlargement (uncommon)

307
Q

How can you treat left atrial rupture/tears?

A
  • Pericardiocentesis, blood transfusion, thoracotomy to remove clots and repair atrium
  • Guarded-grave prognosis
308
Q

Give some causes of infectious/inflammatory pericarditis

A
  • Foreign body, penetrating wound (dog bite, trauma), infectious agent
  • FIP in cats
309
Q

How do you treat infectious/inflammatory pericarditis?

A

Aggressive antibiosis

310
Q

Innocent puppy heart murmurs should be gone by which age?

A

6 months

311
Q

Which side of the heart is affected by patent ductus arteriosus?

A

Left

312
Q

Describe patent ductus arteriosus

A
  • Shunt from descending aorta to pulmonary artery (left to right shunt)
  • Continuous murmur
  • Continuous run-off of blood into pulmonary circulation
  • Pulmonary over-circulation (increased pulmonary vessel size on radiographs)
  • Volume overload of left atrium and ventricle
  • Dilation of mitral valve annulus -> mitral regurgitation
  • L-CHF by 7rs old if untreated
313
Q

Which breeds and sex of dogs are more afected by patent ductus arteriosus?

A
  • Collies, Bichon Frise, CKCS, GSD

- Female

314
Q

How does the femoral pulse sound with patent ductus arteriosus?

A

-Bounding, ‘water hammer’

315
Q

Describe Eisenmenger’s physiology

A
  • In some cases of PDA, if pulmonary arterial pressures are sufficiently increased, the shunt may then reverse, from the pulmonary artery to the descending aorta (reverse PDA)
  • The murmur may disappear (equalisation of pressures between aorta and pulmonary artery)
  • Animal may show caudal cynosis, and will present with HL weakness or collapse
  • Rare in dogs, more common in cats with PDA
316
Q

Give the clinical signs of patent ductus arteriosus

A
  • Initially may be asymptomatic
  • Continuous murmur, left axilla, may radiate
  • Secondary murmur (systolic, mitral regurgitation)
  • Rapidly collapsing femoral pulse (‘water hammer’)
317
Q

How do you diagnose patent ductus arteriosus?

A
  • Radiography
  • ECG
  • Doppler echocardiography
318
Q

What would you see on a radiograph of patent ductus arteriosus?

A
  • Left atrial and left ventricular enlargement
  • Increased size of pulmonary vessels (over-circulation)
  • ‘Triple knuckle effect’: enlargement of pulmonary artery, aorta and left auricular appendage
319
Q

What would you see on an ECG of patent ductus arteriosus?

A
  • Evidence of LA and LV enlargement
  • P mitrale (wide p wave -> left atrial enlargement)
  • Tall r waves -> left ventricular hypertrophy
320
Q

What would you see on an echocardiography of patent ductus arteriosus?

A
  • Diastolic turbulence in the pulmonary artery
  • Enlarged left atrium and ventricle, dilated pulomary trunk
  • Ductus entering pulmonary artery
321
Q

How do you treat patent ductus arteriosus?

A

Surgery:

  • Ligation of ductus
  • Device-based occlusion of the ductus by cardiac catheterization (devices encourage clot formation which occludes flow)
322
Q

What is the most common congenital heart defect in dogs?

A

Aortic stenosis

323
Q

Give some dog breeds that are predisposed to aortic stenosis

A

GSD, Boxer, Newfoundland, Rottweiler

324
Q

How can the left ventricle be affected by aortic stenosis?

A

Pressure overload on left ventricle -> concentric hypertrophy (smaller lumen size)

325
Q

Give some clinical signs of aortic stenosis

A
  • Exercise intolerance
  • Syncope
  • Ventricular arrhythmias if coronary perfusion is compromised
  • L-HF (rare)
326
Q

Where is the point of maximal intensity of an aortic stenosis murmur?

A

Left base (radiates to right heart base and thoracic inlet)

327
Q

What would you see on a radiograph of aortic stenosis?

A

May see aortic arch bulge

328
Q

Describe the heart murmur heard with aortic stenosis

A

Harsh, ejection-type, heard between 1st and 2nd heart sounds

329
Q

What may you see on an ECG of aortic stenosis?

A
  • Tall r waves, prolonged QRS (left ventricular enlargement and hypertrophy)
  • Ventricular premature complexes (QRS without a p)
330
Q

What may you see on a doppler echocardiography of aortic stenosis?

A
  • Valvular/subvalvular lesions
  • Post-stenotic dilation of aorta
  • Turbulence in the LV outflow tract and aorta (velocities >2.0 m/s)
331
Q

How do you convert Doppler velocity into pressure gradient?

A

-Modified Bernouilli equation

P=4v2 (squared)

332
Q

Which value represents normal aortic velocity?

A

<1.7m/s

333
Q

Give the pressure gradient values of mild, moderate and severe aortic stenosis

A
0-40mmHg= mild
40-80mmHg= moderate
>80mmHg= severe
334
Q

Breed schemes for aortic stenosis exist for which dog breeds?

A

Boxer and Newfoundland

335
Q

How do you treat aortic stenosis?

A
  • No real treatment
  • Beta blockers may reudce risk of sudden death in dogs with syncope
  • If in CHF, give diuretics
  • Avoid positive inotropes (eg pimobendan)
336
Q

Give some dog breeds which are predisposed to pulmonic stenosis

A
  • Boxer
  • Bulldogs
  • Bull mastiffs
  • Cocker spaniels
  • WHWT
337
Q

How does pulmonic stenosis usually occur?

A

Valves are fused together or have dysplastic valve leaflets (RHS)

338
Q

Where do coronary arteries arise from?

A

Aorta

339
Q

What are the clinical signs of pulmonic stenosis?

A
  • Mid to holo-systolic heart murmur, left heart base, radiating dorsally
  • Syncope
  • Exercise intolerance
  • May be asymptomatic
340
Q

How does pulmonic stenosis affect the right ventricle?

A
  • Increased pressure load on right ventricle -> concentric right ventricular hypertrophy and marked increases in right ventricular pressure
  • RV hypertrophy may lead to myocardial ischaemia ->ventricuar arrhythmias
341
Q

How do you diagnose pulmonic stenosis?

A
  • Radiography
  • ECG
  • Doppler echocardiography
342
Q

What would you see on a radiograph of pulmonic stenosis?

A
  • Right sided enlargement (increased sternal contact) (reverse D shape on DV view)
  • Dilation of pulmonary artery (bulge at 1 or 2 o’clock on DV radiograph)
343
Q

What would you see on an ECG of pulmonic stenosis?

A
  • Right ventricular enlargement and hypertrophy

- Deep s waves in leads I, II and aVF

344
Q

What would you see on a doppler echocardiography of pulmonic stenosis?

A

-Interventricular septum may be flattened and pushed into the LV
-Dysplastic pulmonic valves
-Post-stenotic dilation of pulmonary valves
(Pressure overload of right ventricle)

345
Q

How do you treat pulmonic stenosis?

A

-Balloon vulvoplasty of pulmonic valve (cardiac catheterisation) (aim is to reduce pressure gradient by 50%)

346
Q

How is murmur grade related to severity of disease with ventricular septal defects?

A
  • Inversely proportionate
  • Small defects= large murmurs
  • Large defects= quiet murmurs
347
Q

Where are vetricular septal defects located in small animals?

A

-In the peri-membraneous septum, “between” the aortic and tricuspid valve leaflets

348
Q

What kind of shunt is most commonly seen in ventricular septal defects? Why?

A
  • Left to right shunt

- Most defects are small and restrictive -> pressure gradient is maintained between LV and RV

349
Q

How does a ventricular septal defect affect the ventricles?

A

-Left to right shunt -> volume overload in right ventricle -> pulmonary over-circulation -> LA and LV volume overload

350
Q

How do you diagnose ventricular septal defects?

A
  • Radiography
  • ECG
  • Echocardiography
351
Q

What would you see on a radiograph of a ventricular septal defect?

A
  • Left sided and right ventricular enlargement

- Pulmonary over-circulation (increased size of lobar vessels)

352
Q

What would you see on an ECG of a ventricular septal defect?

A

-May be normal or show changes consistent with biventricular enlargement (deep Q waves, tall R waves) or left atrial enlargement (p mitrale)

353
Q

What would you see on a doppler cardiography of a ventricular septal defect?

A

-Facilitates detection of the shunt

354
Q

Give some possible sequelae to ventricular septal defects

A
  • Small restrictive VSDs remain asymptomatic
  • Large defects: L-HF
  • Occasionally, the aortic valve leaflet may “prolapse” into the defect -> aortic incompetence (regurgitation) and possibly an audible diastolic murmur
  • If pulmonary hypertension is present, high RV pressures may result in shunt reveral (Eisenmenger’s syndrome)
355
Q

What is Eisenmenger’s sydrome?

A
  • Rare consequnece of a ventricular septal defect
  • If pulmonary hypertension is present, high RV pressures may result in shunt reveral (as RV pressure is greater than LV pressure)
  • Cyanosis of mm
  • Occurs before 6 months old
  • May develop polycthaemia (due to renal hypoxia)
356
Q

Which dog breeds are predisposed to mitral valve dysplasia?

A

Bull terriers, golden retrievers, great danes, GSD

357
Q

Whcich dog breed is predisposed to tricuspid dysplasia?

A

Labradors (canine chromosone 9)

358
Q

Describe the pathophysiology of mitral/tricuspid valve dysplasia

A
  • Incompetece of valve with regurgitation
  • Volume overload of atrium or ventricle
  • Heart failure
  • Possibly arrhythmias
  • Occasionally get stenosis of valve -> gross atrial enlargement
359
Q

How may the valve be different from normal in mitral/tricuspid valve dysplasia?

A
  • May be thickened

- May have abnormal papillary muscles or chordae tendinae

360
Q

How might the mitral valve appear on doppler cardiography with mitral valve dysplasia?

A

‘Hockystick’ appearance

361
Q

What might you see on a doppler cardiography of tricuspid valve dysplasia?

A

Right atrium bigger than left atrium

362
Q

Which direction ins shunting with atrial defects?

A

Usually left to right, except in conditions with raised right atrial pressure (eg concurrent pulmonic stenosis)

363
Q

How do you diagnose atrial septal defects?

A

Doppler echocardiography

364
Q

Give the components of Tetralogy of Fallot

A
  • Pulmonic stenosis -> high RV pressure
  • Right ventricular hypertrophy
  • Ventricular septal defect (right to left shunt)
  • Dextrapposed aorta (aorta positioned more to the right than normal -> compresses pulmonary artery)
365
Q

How may an animal present if it has Tetralogy of Fallot?

A
  • Cyanotic (and fails to respond to O2 supplementation)

- May become polycythaemic -> increased blood viscosity -> increased work load on heart

366
Q

Give some other congenital heart conditions that are not associated with a heart murmur

A
  • Vascular ring anomalies

- Pericardio-peritoneal diaphragmatic hernia

367
Q

Describe vascular ring anomalies

A
  • Usually a persistent right fourth aortic arch
  • Results in a vascular ring surrounding the oesophagus
  • Mega-oesophagus rostral to the ring can occur
368
Q

Give a clinical sign of vascular ring anomalies

A

Regurgitation at the onset of weaning/intake of solid foods

369
Q

Give some examples of bronchodilators

A

Terbutaline
Theophylline
Etamiphylline camsilate
(B2 agonists)

370
Q

Give an example of a mucolytic

A

Bromhexamine

371
Q

What is ‘feline asthma’?

A

Eosinophilic bronchopneumopathy (EBP)

372
Q

What are the clinical signs of feline asthma?

A

Cough
Can have severe dyspnoea (expiratory)
May hear expiratory wheezes on auscultation

373
Q

What might you hear on cardiac auscultation of a dog with a pulmonary thromboembolism?

A

Loud S2 (due to pulmonary hypertension and delayed closure of pulmonic valve)

374
Q

Give some causes of pleural effusion

A

Increased hydrostatic pressure
Decreased plasma oncotic pressure
Increased vascular or pleural permeability (eg inflammation)
Increased fluid production (eg infection)

375
Q

Why may a blood clot form? (3)

A

Circulatory stasis
Endothelial injury
Hypercoagulable state
(Virchow’s triad)

376
Q

What is the difference between eccentric and concentric ventricular hypertrophy?

A

Eccentric: volume overload. Wall thickness increases in proportion to the increase in chamber radius
Concentric: chronic pressure overload. Wall thickness increases but chamber radius does not change -> stiff ventricle

377
Q

What is S1?

A

Sound of AV valves snapping shut

378
Q

What is S2?

A

Ventricles relax and semi-lunar valves snap shut

379
Q

What is S3?

A

‘Gallop’

End of early diastolic filling -> vibration in ventricle

380
Q

What is S4?

A

During late diastolic filling, the atria contract, squeezing more blood into an already-full ventricle

381
Q

How do you calculate cardiac output?

A

HR x SV

382
Q

Define stroke volume

How do you calculate it?

A

Volume of blood pumped from left ventricle per beat

End diastolic volume-end systolic volume

383
Q

Where does the myocardium obtain most of its blood supply?

A

Coronary circulation

384
Q

Where are the heart valves located?

A

Tricuspid: rib space 5, right axilla

Pulmonary: rib space 3
Aortic: rib space 4
Mitral: rib space 5
all left axilla

385
Q

On an ecg, what does a tall p wave mean?

A

P pulmonale (R atrial enlargement)

386
Q

On an ecg, what does a wide p wave mean?

A

P mitrale (L atrial enlargement)

387
Q

On an ecg, what does a tall r wave mean?

A

Ventricular enlargement

388
Q

On an ecg, what does a wide r wave mean?

A

Left ventricular enlargement and hypertrophy

389
Q

On an ecg, what does it mean if you have no p waves?

A

Atrial fibrillation
Irregularly irregular ventricular rhythm
Normal narrow QRS complexes

390
Q

Give some diseases associated with secondary systemic hypertension?

A

Chronic renal disease
Hyperthyroidism (cats)
Hyperadrenocorticism
Diabetes mellitus

391
Q

Give some consequences of systemic hypertension

A

Ocular (retinal detachment, hyphaema, retinal haemorrhage, blindness)
CNS (seizures, depression)
Renal (failure, proteinuria)

392
Q

How do you treat systemic hypertension?

A

Amlodipine (calcium channel antagonist)

Can use ACE inhibitors to protect the kidneys (reduce glomerular capillary pressure)

393
Q

How do you measure vertebral heart score?

What are the normal values in dogs and cats?

A

Measure long axis and short axis of heart on a radiograph. Transpose each onto vertebral column (from T4) and add the number of vertebrae.
Dog: >10.5
Cat: 8

394
Q

Which receptors do beta blockers act on?

A

Beta adrenergic receptors (epinephrine/norepinephrine)

395
Q

What effects do beta blockers have?

A

Reduce HR
Prolong diastole
Decrease CO
Decrease BP

396
Q

On an echocardiogram, what should the ratio in size of the left atrium to aorta be?

A

1.5:1

397
Q

How will the left ventricle act on an echocardiogram in a dog with mitral valve disease?

A

Will be hyperkinetic to compensate for the mitral valve regurgitation

398
Q

How do you diagnose a sinus arrhythmia?

A

ECG (regularly irregular)

399
Q

What effect does Pimobendan have on heart size?

A

Decreases it

400
Q

Where does the left atrium sit in the chest?

A

Between the caudal lobar bronchi

401
Q

Where should the trachea lie on a radiograph?

A

Parallel to the sternum

402
Q

In which breed can we allow for a bigger vertebral heart score than normal?

A

CKCS

403
Q

Is CHF always primary or secondary?

A

Secondary

404
Q

How do you treat feline hypertrophic cardiomyopathy?

A
Beta blockers (eg atenolol) to reduce HR and enhance filling and relaxation of ventricles
Calcium channel blockers (eg Diltiazem)
Diuretics if in CHF (furosemide, spironolactone)
Anticoagulants (eg aspiring, clopidogrel)
405
Q

How do ACE-inhibitors work?

A

Cause vasodilation by inhibiting RAAS

-> reduces preload and afterload

406
Q

On an US, what are ‘wet lungs’?

What do they indicate?

A

Bright white lines arising from the pleura and radiating away from the probe
Indicates conditions such as pulmonary oedema, pneumonia, contusions

407
Q

How does Pimobendan work?

A

Positive inotrope
PD-3 inhibitor
Causes vasodilation
Premature use can cause left ventricular hypertrophy

408
Q

Which lung lobe sites over the heart in a left lateral radiograph?

A

Right middle

409
Q

What is the only way to diagnose arrhythmias?

A

ECG

410
Q

How do you estimate mean electrical axis on an ECG?

A

Look for the lead with the largest QRS complex, or the isoelectric lead (
r wave =s wave) and pick the lead perpendicular to it

411
Q

What would we expect a normal MEA value to be?

A

+40 to + 100

as this is roughly where Lead II is

412
Q

When might you see a bifid p wave on an ECG?

A

Large breed dogs

413
Q

What would you suspect if the height of the r wave changes throughout the ECG?

A

Heart is swinging in chest due to pericardial effusion (‘electrical alternans’)

414
Q

What is a consolidated lung?

A

Filled with fluid eg blood, pus, oedema

415
Q

The Dirofilaria antigen test only detects what?

A

Mature females

416
Q

What can you do if you suspect pleural effusion in a severely dyspnoeic animal?

A

Radiographs may cause stress so do a standing US to look for fluid
With animal in sternal recumbency and giving oxygen, do ‘blind’ or US-guided thoracocentesus
Use 21G 1” needle, at 7-8th intercostal space. If +ve tap, continue to drain and submit samples for analysis

417
Q

What is the difference between a transudate and modified transudate, appearance-wise?

A

Transudate: clear, watery

Modified transudate: straw-coloured, serosanguinous, slightly viscous

418
Q

What is the difference between a transudate, modified transudate and exudate in terms of cytology and analysis?

A

Exudates have higher protein levels and are more cellular, followed by modified transudates, then transudates

419
Q

Give some possible causes of transudates and modified transudates in a pleural effusion

A

Transudate: hypoalbuminaemia

Modified transudate: right-sided or biventricular CHF, diaphragmatic rupture, neoplasia

420
Q

How do you treat pleural effusion after thoracocentesis?

A

If due to pericardial effusion, rapidly carry out pericardiocentesis
If due to CHF, treat as CHF
If due to hypoproteinaemia, investigate and treat underlying cause

421
Q

Give some examples of appearance of an exudative pleural effusion

A

Bloody
Non-septic inflammation: viscous, straw-coloured
Septic inflammation: viscous, turbid, purulent
Chylous (milky)

422
Q

Give some possible causes of an exudative pleural effusion

A

Bloody: trauma, neoplasia, coagulopathy
Non-septic inflammation: lobe torsion, neoplasia, chronic chylothorax
Septic inflammation: ruptured oesophagus, FB, pylothorax, fungal infection
Chylous: idiopathic, CHF, trauma, lobe torsion, cranial vena cava obstruction

423
Q

How do you treat pyothorax?

A

Do C&S on thoracocentesis and base ABs off the results.
Initially, start combination of ABs for broad-spectrum coverage (eg metronidazole, potentiated amoxycillin, fluoroquinalone)
When stable, insert chest drain under GA
Daily thoracic lavage (up to 20ml/kg warm saline)
Once lavage is clear, can pull drains
Continue ABs for 2-3 months

424
Q

How do you treat chylothorax following thoracocentesis?

A

Treat underlying cause (eg CHF)
Feed low fat diet (high CHO) (reduces chyle production)
Add medium-chain triglycerides to diet?
Rutin may reduce chyle formation (20-50mg/kg q8hrs)
Consider surgery

425
Q

Give some causes of ventricular ectopics

A
Underlying cardiac disease 
Catecholamines (eg stress, pain)
Acidosis
Hypokalaemia
Abdominal disease
Thoracic trauma
426
Q

Give some underlying causes of brady-arrhythmias

A

High vagal tone
Hyperkalaemia
Hypothyroidism
Drug side-effects

427
Q

How would you recognise atrial standstill on an ecg?

A

No p waves
Normal QRS complexes
T waves are spiky and symmetrical

428
Q

What causes atrial standstill?

A

Hyperkalaemia

429
Q

What would you see on an ecg of sinus arrest?

A

Period of no heartbeat followed by a junctional escape complex

430
Q

What can cause pulse deficits?

A

Atrial fibrillation

431
Q

Which sedatives should you avoid when sedating a dog with MDVD?

A

Alpha 2’s

432
Q

How are veins positioned on a radiograph?

A

Ventral and central (always travel with an artery and an airway; artery, airway, vein)

433
Q

What could you give to treat preclinical MDVD?

A

Pimobendan

Can halt progression of MDVD to CHF

434
Q

Which drugs could you give to treat a ventricular arrhythmia associated with MDVD?

A

Sotalol
Mexillitine? (sodium channel blocker)
Amiodarone

435
Q

Which drugs could you give to treat pulmonary hypertension associated with MDVD?

A

Sildenafil (vasodilator)

Pimobendan (vasodilator)

436
Q

What is the normal urine protein:creatinine ratio?

A

<0.2

437
Q

What would you see on an ECG of supraventricular premature complexes and why?

A

Premature p waves (premature activation of atria from a site other than sinus node)

438
Q

What is the normal number of VPCs you would tolerate in an ambulatory ecg of a normal dog?

A

<4/24 hours

439
Q

What does the sternal lymph node drain?

A

Cranial abdomen and thoracic wall

440
Q

Why may a heart have increased sternal contact on a radiograph?

A

RV enlargement

441
Q

How would you diagnose right arrhythmogenic ventricular cardiomyopathy on a halter ECG?

A

> 1000 ventricular premature complexes over 24 hours

442
Q

Where do nasopharyngeal polyps arise from in cats?

A

Auditory (Eustachian) tube or tympanic bulla

Extend into pharynx or along external ear canal