Arrhythmias - pathophysiology, presentation & investigation#

Question 1

Features of arrhythmias

Answer 1

• Asymptomatic
• Palpitations, dyspnoea, chest pain, fatigue
• Embolism

Question 2

Investigation of arrhythmias

Answer 2

• Document arrhythmia on ECG: 12 lead, 24 hour recording, event recorder
• Blood tests esp thyroid function
• Echocardiogram

Question 3

Therapeutic approaches for arryhythmias

Answer 3

Rate control versus rhythm control:

• DIgoxin/beta-blocker/Ca-antagonit plus warfarin versus class Ic/III drugs +/- DC cardioversion
• Electrical approaches: pace & ablation of AV node, substrate modification e.g. pulmonary ostial ablation, maze procedures
• Consider anticoagulation: based on the scoring system

Question 4

Features of supraventricular tachycardia

Answer 4

AV-nodal re-entrant tachycardia

• C/O palpitations, dyspnoea, dizziness
• Good prognosis

AV re-entrant tachycardia (due to accessory pathway-WPW if overt):

• Usually good prognosis
• No treatment
• Drugs (so-so) or RFA

Question 5

Treatment for atrial flutter

Answer 5

• Control ventricular rate & thromboembolic risk
• Usually cardiovert
• Prevent with AA drugs or RFA of cavotricuspid isthmus

Question 6

Features of ventricular tachycardia

Answer 6

• Palpitations, CP, dyspnoea, dizziness, syncope
• Usually structural heart disease
• Take bloods, echo, angio etc

Question 7

What is Torsades de Pointes caused by?

Answer 7

Long QT syndrome

• congenital or acquired
• May cause TdP
• Px drugs, pacing or ICD

Question 8

Indications for ICD (implantable cardioverter defibrillator) therapy

Answer 8

Secondary prevention

• Cardiac arrest due to VF/VT not due to transient or reversible cause e.g. early phase of acute MI
• Sustained VT causing syncope or significant compromise
• Sustained VT with poor LV function

Question 9

What are indications for temporary pacing?

Answer 9

• Intermittent or sustained symptomatic bradycardia, particularly syncope.
• Prophylactic when patient at high risk for development of severe bradycardia e.g. 2nd or 3rd degree AV block, postanterior MI, even when asymptomatic

Question 10

Indications for permanent pacing

Answer 10

• Symptomatic or profound 2nd/3rd degree AV block, particularly when cause unlikely to disappear
• Probably Mobitz type II 2nd/3rd degree AV block even if asymptomatic
• AV block associated with neuromuscular diseases
• After (or in preparation for) AV-nodeablation
• Alternating RBBB/LBBB
• Syncope when bifascicular/trifascicular block and no other explanation
• Sinus node disease associated with symptoms
• Carotid sinus hypersensitivity/malignant vasovagal syncope