Cardio ECG #2

Question 1

Common causes of bradyarrhythmias- non p athologic

Answer 1

Abnormalities of autonomic tone (i.e. patient under general anesthesia with lower symp tone, etc)

Question 2

Other cause of bradyarrhytmias

Answer 2

1) Sinus node issue: decreased rate of P waves or absent P waves
2) AV node issue: Slow/absent conduction through the AV node; P waves WITHOUT QRS

Question 3

SINUS bradycardia/bradyarrhytmias: what do you see on ECG

Answer 3

Normal P wave for every QRS, but P and QRS occur at a slow rate
Normal PR interval
Normal QRS

Bradyarrthmias- different interval lengths (vs bradycardia has same interval lengths)

Question 4

Treatment of Sinus bradycardia

Answer 4

Sinus bradycardia usually a response to other systemic issues

• high vagal tone (diseases of GIT, Pulmonary system, brain)
• anesthesia/sedation (may need atropine)
• medications
• *I.d. and address underlying cause

Question 5

Sick sinus syndrome- which breeds?

Answer 5

Abnormal rhythm disturbances in older, small breed dogs (Schnauzer, dachshund, WHWT, cocker)

Question 6

Sick sinus syndrome involves a combo of what?

Answer 6

Sinus bradycardia
Sinus arrest (pause without any P or QRS)
AV block
Supraventricular tachycardia (esp after long pause)

Question 7

AV node disease- effect on P wave rate, PR interval

Answer 7

Normal or elevated P wave rate
Decreased rate of conduction from P to QRS (LONG PR interval)
or can see complete block of conduction through AV node = AV block

Question 8

Three types of AV block

Answer 8

First degree, second degree, third degree

Question 9

First degree AV block

Answer 9

Usually vagal tone

PR distance is too long

Question 10

Second degree AV block (normal in which species? when is it seen in dogs? how to differentiate?)

Answer 10

normal in horses
dogs- high vagal tone or AV node dz
differentiate with atropine (if physiologic and vagally mediated, will resolve)

Question 11

Third degree (complete) AV block

Answer 11

P and QRS are regular, but not related

Ventricular (QRS) activity is from ESCAPE foci in AV node or ventricle (wide/bizarre)

Question 12

How to treat 3rd degree AV block

Insignificant in what?

Answer 12

Pacemaker implantation (~$3000. Lifespan ~7 years. Prognosis good if no other major dzs)
Generally not responsive to medical treatment

Insignificant in very geriatric cats

Question 13

3 types of tachycardia

Answer 13

Sinus, Supraventricular, Ventricular

Question 14

Sinus tachycardia: what is it? what causes it? treatment?

Answer 14

Increased HR that originates in sinus node

Response to systemic issues (Pain, excitement, fear, hypotension under surgery)

Address the primary cause

Question 15

Supraventricular tachycardia definition

Answer 15

3+ supraventricular beats (SVPCs) in a row

Abrupt, irregular (starting and ending suddenly)

Question 16

What are the most common causes of supraventricular tachycardia? These are OK in what species ?

Answer 16

Atrial enlargement ****
Enlarged hilar LN
Thoracic masses
Pulmonary inflammation
Elyte disturbances 

HORSES can have SV tachycardia without structural heart dz

Question 17

Atrial fibrillation is a type of _____

Answer 17

SV tachycardia

Question 18

A Fib (describe HR, RR intervals, P waves, F waves)

Answer 18

Rapid heart rate, irregularly Irregular RR interval, no obvious P waves, +- f waves

Question 19

Small animals- when is A fib most commonly observed, which species

Answer 19

With severe atrial enlargement

• DCM
• Chronic valvular disease
• other causes possible

Fairly uncommon in cats, but HCM can cause it

Question 20

Treatment of Canine SVT and a fib (goal? do you expect a return to normal rhythm? which drugs)

Answer 20

Goal= decrease HR to normal range by decreasing ventricular response rate of conduction through AV node (Basically- slow HR down, decrease O2 consumption, decrease workload)

Don’t expect a return to normal rhythm

Drugs

• calcium channel blocker (Diltiazem)
• Digoxin
• Beta Blocker (Atenolol, sotalol)
• Combos (Dig + Diltiazem)

Question 21

Equine A fib

Answer 21

note that we use Base ape leads so their QRS look negative

Question 22

Equine (lone) A fib

what is lone? impact on performance? treatment? relapses ?

Answer 22

Lone = no evidence of structural heart disease, and successful TX often converts it back to NORMAL sinus rhythm

Negative impact on performance

Treatments

• Quinidine *+digoxin
• or Amidarone
• *treat ASAP for good respinse
• *relapses common

Question 23

Bovine Atrial Fibrillation most often associated with what? Treatment?

Answer 23

Primary GI disease

Once primary dz addressed, arrhythmia resolves . So may not need treatment

Question 24

Ventricular Tachycardia definition

What does paroxysmal mean?

Answer 24

3+ VPCs in a row

• sustained
• paroxysmal (means intermittent )

Question 25

Vtach treatment considerations

Answer 25

Antiarrhythmics decrease risk of VT, but do not guarantee avoidance of sudden death!! Many are actually proarrhytmic (can make arrhytmia worse or better) MAKE SURE YOU HAVE INDICATIONS TO TREAT

Question 26

indications to treat Vtach (long list of 8 things)

Answer 26

1) paroxysms or sustained VT >140-160BPM 2) >20 VPCs per min 3) Multiform VPCs 4) Arrhythmia with MYOCARDIAL FAILURE present 5) Breeds at risk for SUDDEN DEATH (Doberman, Boxers) 6) Clinical signs of hypotension 7) VPCs close to T wave of the PRECEDING complex (R on T phenomenon) 8) Critically ill patients

Question 27

Acute/Emergency treatment of Vtach

Answer 27

Lidocaine= IV bolus --> good response --> can switch to CRI Side effects = CNS (seizures), vomiting, use cautiously in cats (lower dose)

Question 28

Vtach chronic therapy

Answer 28

Oral * Mexilitine (similar to lidocaine) * Sotalol (beta blocker/class 3) * Atenolol (beta blocker)

Question 29

Ventricular Fibrillation - what is it? treatment?

Answer 29

Disorganized electrical activity, END RESULT OF VTACH, NO PULSES --> DEATH Electrical defibrillation. ANTIARRHYTHMICS NOT EFFECTIVE