Arrhythmias

Question 1

What is meant by a supra-ventricular arrhythmia?

Answer 1

An arrhythmia in which the origin is supernal to the ventricles, including the SAN, Atrial myocardium, AV node or His origin

Question 2

What are some examples of supra ventricular tachycardias?

Answer 2

Atrial fibrillation
Atrial flutter
Ectopic atrial tachycardia

Question 3

What are some examples of supra ventricular bradycardias?

Answer 3

Sinus bradycardia
Sinus pauses

Question 4

What are some examples of ventricular arrhythmias?

Answer 4

Ventricular ectopics or premature ventricular complexes
Ventricular tachycardia
Ventricular fibrillation
Asystole

Question 5

What are some examples of Atrio-Ventricular Node arrhythmias?

Answer 5

AV Node re-entry tachycardia
AV reciprocating or AV re-entrant tachycardia
AV Block (1st, 2nd, 3rd degree)

Question 6

What are some clinical causes of arrhythmias?

Answer 6

Abnormal anatomy allowing re-entry circuits
Autonomic nervous system
Metabolic causes
Inflammation
Drugs
Genetic

Question 7

What are some examples of ways in which the autonomic nervous system can result in arrhythmia?

Answer 7

Sympathetic stimulation due to stress, exercise, hyperthyroidism
Increased vagal tone causing bradycardia

Question 8

What are some examples of metabolic causes of arrhythmias?

Answer 8

Hypoxia - Chronic pulmonary disease, pulmonary embolism
Ischaemic myocardium - Acute MI, angina
Electrolyte imbalance

Question 9

What is an example of an inflammatory cause of arrhythmia?

Answer 9

Viral myocarditis

Question 10

What is an example of a genetic cause of arrhythmia?

Answer 10

Congenital long QT syndrome

Question 11

What is meant by an ectopic beat?

Answer 11

A rhythm that originates in places other than the SA node

Question 12

What occurs in Wolf Parkinson White syndrome?

Answer 12

An extra conduction pathway forms in the heart allowing the bypassing of the AV node, therefore decreasing the PR interval and predisposing the person to supraventrcular tachycardia

Question 13

What are some example of conditions that increase the phase 4 (funny current) slope of the SA node, and thus increase heart rate?

Answer 13

Hyperthermia
Hypoxia
Hypercapnia (High CO2)
Myocardial stretch

Question 14

What are some examples of conditions that decrease the phase 4 (Funny current) slope and thus decrease heart rate?

Answer 14

Hypothermia
Hyperkalaemia

Question 15

What ate the 2 main classes of triggered activity?

Answer 15

Delayed After-depolarisations
Early After-depolarisations (Phase 2 and 3)

Question 16

What are some examples of conditions that result from prolonged after-depolarisations?

Answer 16

Digoxin toxicity
Torsades du Pointes in long QT syndrome
Hypokalaemia

Question 17

What occurs in re-entry?

Answer 17

An action potential fails to extinguish itself and reactivates a region that has depolarised. This can occur in the presence of an obstacle around which an action potential can travel (Circus entry)

Question 18

What are some common symptoms of arrhythmias?

Answer 18

Palpitations
Dyspnoea
Pre-syncope
Syncope
Shock
Sudden cardiac death
Angina
Heart failure
Anxiety

Question 19

What investigates can be performed on someone with a suspected arrhythmia?

Answer 19

12 lead ECG
Bloods
Chest X-ray
Echocardiogram
Stress ECG
24-hour ECG Holter monitoring
Event recorder (Press a button to turn on ECG when the patient feels an arrhythmia)
Electrophysiological study

Question 20

What can be done during an electrophysiological study?

Answer 20

The arrhythmia can be triggered to study its pathway and origin and then radio frequency ablation (Cauterisation of the origin to cause fibrosis) can be performed

Question 21

What is meant by normal sinus arrhythmia?

Answer 21

Variation in heart rate due to reflex changes in vagal tone during respiration
Inspiration reduces vagal tone and thus increases heart rate

Question 22

What are some causes of Sinus bradycardia?

Answer 22

Physiological e.g. in an athlete
Drugs such as ß-Blockers
ischaemia

Question 23

What is the treatment for acute sinus bradycardia, such as in an acute MI?

Answer 23

Atropine and pacing (If there is haemodynamic compromise)

Question 24

What are some causes of sinus tachycardia?

Answer 24

Anxiety
fever
Hypotension
Anaemia
Drugs

Question 25

What are the treatment options for sinus tachycardia?

Answer 25

ß-Blockers Treatment of the underlying cause

Question 26

What are the 2 types of AV reciprocating tachycardia?

Answer 26

Orthodromic AVRT - Impulse travel from ventricular walls back to the AV node where it forms a circuit Antidromic AVRT - Impulses travel from the AV node and directly into the ventricular wall, without the bundles of His

Question 27

What are some acute management strategies for supraventricular tachycardia?

Answer 27

Increase vagal tone - Valsalva, carotid massage Slow AV node conduction - IV Adenosine and verapamil

Question 28

What are some chronic management strategies for supra ventricular tachycardia?

Answer 28

Avoid stimulants Radiofrequency ablation and Electrophysiological study ß-Blockers Anti-arrhythmic drugs

Question 29

What are some causes of AV node conduction block?

Answer 29

Ageing Acute MI Myocarditis Amyloidosis ß-Blockers Ca2+ channel blockers Calcific aortic valve disease Post-aortic valve surgery Genetic - Lenore's disease, myotonic dystrophy

Question 30

What is meant by 1st degree AV blocK?

Answer 30

AV nodal delay >0.2seconds, but without any symptoms

Question 31

What is meant by 2nd degree AV block?

Answer 31

Intermittent block at the AV node leading to a dropped beat

Question 32

What are the 2 types of 2nd degree heart block?

Answer 32

Mobitz type I Mobitz type II

Question 33

What is meant by Mobitz type I 2nd degree heart block?

Answer 33

Progressive lengthening of the PR interval (AV node delay) leading up to a dropped beat

Question 34

What is meat by Mobitz type II 2nd degree heart block?

Answer 34

Constant 2:1 or 3:1 drop in beats Requires permanent pacing

Question 35

What is meant by 3rd degree AV node block?

Answer 35

Complete loss of communication between the SA and AV node Required ventricular pacing

Question 36

What are the 2 types of pacemaker?

Answer 36

Single chamber (Paces only the right atria or ventricle) Dual chamber (Paces both RA and RV)

Question 37

What are the 2 types of ventricular tachycardia?

Answer 37

Monomorphic - Regular pattern for tachycardia Polymorphic - Chaotic tachycardia with no clear pattern

Question 38

What is meant by ventricular fibrillation?

Answer 38

Chaotic ventricular electrical activity which causes the heart to fail to pump

Question 39

What is the treatment for ventricular fibrillation?

Answer 39

Defibrillation and CPR

Question 40

What are some acute treatment strategies for Ventricular tachycardia?

Answer 40

Direct current cardioversion Correct triggers

Question 41

What are some chronic treatment strategies for ventricular tachycardia?

Answer 41

Revascularisation Anti-arrhytmic drugs (Associated with worse outcomes on their own) Implantable cardiovertor defibrillator catheter ablation