Chronic CV Diseases - 2

Question 1

What are cardiac arrhythmias?

Answer 1

disorders of heart rate

Question 2

What are the fast (tachy) arrhythmias?

Answer 2

• atrial fibrillation
• ventricular tachycardia

Question 3

What are the slow (Brady) arrhythmias?

Answer 3

• heart block
• Drug induced! (b blocker, digoxin)

Question 4

What is the most common cause of pulse around 50bpm?

Answer 4

drug induced
- beta blocker

Question 5

What is heart block and what are the 3 classifications ?

Answer 5

• slow/no conduction through the AV node to ventricles of impulse from SA node
• Prolonged p-q interval on ECG
• Mild delay: Signals get through slowly (1st degree).
• Some blocks: Occasional skipped beats (2nd degree).
• Complete block: Needs pacemaker (3rd degree).

Question 6

How do fast heart rates impair cardiac function?

Answer 6

• reduced diastolic filling time therefore reducing cardiac output and leading to heart failure

Question 7

What is the difference in ECG between atrial and ventricular tachyarrhythmia?

Answer 7

atrial - narrow ORS, no P wave
ventricular - broad strange QRS

Question 8

Why is ventricular tacharrthymia dangerous?

Answer 8

leads to ventricular fibrillation and death

Question 9

What are cardiac pacemakers used to treat?

Answer 9

BRADYARRHYTHMIAs

Question 10

What do cardiac pacemakers do?

Answer 10

• Don’t ‘pace’ the heart if natural heart rate is above a certain level – e.g. 50 bpm
• Maintain a minimum heart rate by providing electrical stimulation.

Question 11

What are the risks of pacemakers?

Answer 11

theoretical risk of electrical interference – causes sensing to shut down

• electrical fields - MRI, electrosurgery/diathermy
• dental equipment THEORETICAL risk only
• Pulp Testers OK - avoid INDUCTION scalers though – these generate strong EM field

Question 12

What do the waves of a sinus rhythm signify?

Answer 12

• P wave – atrial depolarisation
• QRS complex – Ventricular
  depolarisation
• T wave – Ventricular repolarisation

Question 13

What is ventricular fibrillation usually caused by?

Answer 13

• Heartattack
• Electrocution
• Long QT syndrome–can be drug induced
• Wolf-Parkinson-Whitesyndrome

Question 14

How can ventricular fibrillation be treated?

Answer 14

• Treat with ‘Defibrillation’
• Implanted defibrillators used in risk cases

Question 15

What is ventricular fibrillation?

Answer 15

• No cardiac output - Death follows!
• Electrical heart activity but disorganised
• muscle fibres contracting in ventricles at random – no emptying of ventricle

Question 16

What is asystole?

Answer 16

• No cardiac output
• No electrical activity
• Defibrillation not possible (adrenaline used)
• Low chance of survival

Question 17

When should congenital heart defects be suspected?

Answer 17

with ANY body congenital defect (Cleft Lip/Palate, Downs)

Question 18

What are the types of congenital heart defects?

Answer 18

• ATRIAL septal defects
• VENTRICULAR septal defects
• Patent ductus arteriosus
• Great vessel malformations

Question 19

In what diseases is finger clubbing seen?

Answer 19

• Cardiac disease
• Lung diseases
• Inflammatory Bowel diseases
• Liver cirrhosis

Question 20

What is the value for cyanosis?

Answer 20

Cyanosis exists when there is 5g/dl or more of deoxygenated Hb in the blood

Question 21

Central VS Peripheral Cyanosis

Answer 21

Central
Congenital heart disease, lung diseases etc
Poor oxygenation of the blood
Oxygenated and deoxygenated mixing
Mucosa and tongue blue

Peripheral
Cold environment
Slow circulation due to vasoconstriction
Oxygen levels fine
Raynauld’s disease

Question 22

How can you test congenital defects?

Answer 22

doppler ultrasound scan

Question 23

What are qualities of atrial septal defect?

Answer 23

• Most remain undetected throughout life
• Low risk of endocarditis except in IVDA (drug) patients
• Usually non-cyanotic

Question 24

What are the qualities of ventricular septal defect?

Answer 24

• Higher endocarditis risk
• Higher risk of long term heart failure
• Usually non-cyanotic
• Different types present – commonest is in the muscle between the ventricles

Question 25

How can septal defects close?

Answer 25

* Some shrink naturally with time and require no intervention * Open heart surgery and closure directly of the defect via patch * Catheter insertion of a mesh on each side of the defect by arterial access

Question 26

What is co-artctation of the aorta?

Answer 26

narrowing of the aorta just after the carotid artery on the left side has exited. this restricts blood flow to systemic arteries of lower body | birth defect

Question 27

What is a patent ductus arteriosus?

Answer 27

ductus fails to close leading to turbelent blood flow and increased endocarditis risk

Question 28

What is infective endocarditis?

Answer 28

infection of the endocardium usually on the valves

Question 29

What organisms is mainly implicated in infective endocarditis?

Answer 29

oral steptococci (viridans)

Question 30

What is vegetation formation?

Answer 30

Microbial colonisation of thrombi on endocardial surface abnormalities causes areas of thickening and stiffening of the valves

Question 31

What is the cycle of infective endocardiditis

Answer 31

surface abnormalities (inflammation) > haemodynamic changes > turbulence > platelet / fibrin deposition (thrombus) > vegatation > microbial attacgment and multiplication > enlargement of vegetation

Question 32

What is the effect of infective endocarditis?

Answer 32

Prolonged antibiotic treatment (intravenous) - 4+ weeks of bacteriocidal treatment - - Often combinations of drugs Cardiac valve damage - Valve dysfunction - Urgent valve replacement needed

Question 33

Which dental procedures are a risk?

Answer 33

Procedures involving manipulation of the dento-gingival junction and causing a bacteraemia * Extractions * Periodontal therapy * Gingival surgery * Implants * Restorations * Only if the gingival margin involved or matrix used

Question 34

What is bacteraemia?

Answer 34

viable bacteria in the blood

Question 35

What do the NICE guidelines say 2008 for antibiotic prophylaxis?

Answer 35

NO indication for Antibiotic Prophylaxis No indication from literature of benefit Possible harm from Adverse Drug Reaction

Question 36

What should dental efforts be concentrated towards? (via NICE GL 2008)

Answer 36

Dental efforts to be concentrated on reducing risk by reducing size and frequency of oral bacteraemia * Improve patient’s oral hygiene efforts * Remove areas of dental sepsis * – unrestorable carious teeth, teeth causing infection * Work at prevention of oral disease * Diet, hygiene, high fluoride content toothpaste

Question 37

Who are the highest risk patients that may require AB prophylaxis?

Answer 37

o Previous endocarditis o Valve replacement surgery o Certain congenital heart defects

Question 38

What happens to surviors of infective endocarditis?

Answer 38

significantly reduced length & quality of life

Question 39

When is prophylaxis used?

Answer 39

Only for procedures likely to produce a significant bacteraemia * MANIPULATION OF DENTO-GINGIVAL JUNCTION

Question 40

What does the montgomery ruling require for consent to prophylaxis?

Answer 40

“Montgomery” requires: - Consequences of ABP must be discussed - Consequences of NO ABP must be discussed - For cases who are ‘high risk’ undergoing invasive dental procedures – dento-gingival manipulation.

Question 41

What consititues a dentally fit patient?

Answer 41

minimal oral sepsis (active caries) no endodontic disease no periapical/dontal disease