Arrhythmias

Question 1

What are arrhythmias?

Answer 1

Abnormal rhythm due to:
1) Defects in impulse generation
2) Defects in impulse conduction
3) Or a combination of both

Question 2

Tachycardia definition?

Answer 2

HR > 100bpm

Question 3

Bradycardia definition?

Answer 3

HR < 60 bpm

Question 4

Common arrhythmias can be broadly classified into which 2 components? Under each component, list down the subdivided categories of arrhythmias.

Answer 4

1) By speed of the heart rate
- Tachy-arrhythmias
- Brady-arrhythmias
2) By origin in the heart
- Atrial arrhythmias
- Ventricular arrhythmias

Question 5

What is the most prevalent arrhythmia in the SG population?

Answer 5

Atrial fibrillation

Question 6

What causes atrial fibrillation?

Answer 6

AF arises when depolarization stimuli fire off from abnormal areas in the atria, instead from the sinus node
-> bombards the AV node with multiple signals instead of a single signal from the sinus node
-> results in fast and irregular heartbeat
-> loss of meaningful contraction

Question 7

Explain how atrial fibrillation can increase the risk of stroke

Answer 7

Irregular rhythm in AF causes turbulent flow in the left atrium, leading to risk of clot formation
-> clot may embolize and travel to the brain -> stroke

Question 8

State the 3 main treatment approach for atrial fibrillation (hint: ABC)

Answer 8

A: Anticoagulation, avoid stroke
B: Better symptom control
- through either rate control or rhythm control
C: CV risk factors & concomitant diseases
- lifestyle interventions

Question 9

List down common symptoms of atrial fibrillation

Answer 9

1) Racing heart/fluttering/palpitation
2) Fatigue, shortness of breath
3) Lightheadedness

Question 10

Do all patients with atrial fibrillation present with symptoms?

Answer 10

No- some patients can be asymptomatic

Question 11

Atrial fibrillation are usually associated with underlying heart disease that causes atrial distension. List down 3 examples of such conditions

Answer 11

1) Heart failure (both HFrEF & HFpEF)
2) Hypertension (especially longstanding, poorly controlled)
3) Disorders of the heart valves (especially mitral stenosis)

Question 12

What approach is generally the first-line in treatment of atrial fibrillation?

Answer 12

Rate control, unless patient is hemodynamically unstable

Often sufficient to improve AF-related symptoms

Question 13

List down 4 drugs that are used for rate control for AF

Answer 13

1) Beta-blockers
2) Non DHP CCBs
3) Digoxin
4) Amiodarone

Question 14

For rate control of AF- what are the first-line treatment options?

Answer 14

In general: Beta-blockers or non DHP CCBs

• HFrEF: beta-blocker
• Severe COPD/Asthma: Non DHP CCB

Question 14

What is the second-line option for rate control of AF?

Answer 14

In general: Beta-blockers or non DHP CCBs (if it has not been tried)

-HFrEF: as Non DHP CCBs are contraindicated, replace/add digoxin to beta-blockers

• Severe COPD/Asthma patients: beta-blockers contraindicated, replace/add digoxin to non DHP CCBs

Question 14

Comment on amiodarone place in rate control therapy for atrial fibrillation

Answer 14

Used as a 3rd or 4th line drug

Question 15

When is rhythm control usually undertaken?

Answer 15

• If patient is symptomatic despite rate being well controlled
• Patient would benefit from being in sinus rhythm (e.g. young age)
• High likelihood of being able to maintain sinus rhythm (e.g. 1st AF episode, short history, precipitated by a temporary event)