What are the indications for pacemaker implantation?

Indications for Pacemaker Implantation

Pacemaker implantation is strongly indicated for symptomatic bradycardia with complete heart block, second-degree AV block, or sinus node dysfunction, as these conditions significantly impact morbidity, mortality, and quality of life. 1

Class I Indications (Strongest Recommendations)

Complete Heart Block

• Complete heart block (permanent or intermittent) with symptomatic bradycardia 2
• Complete heart block with congestive heart failure 2
• Complete heart block with documented periods of asystole ≥3.0 seconds or escape rate <40 beats/min even in asymptomatic patients 2
• Complete heart block requiring drugs that suppress escape pacemakers 2
• Complete heart block with confusional states that clear with temporary pacing 2

Second-Degree AV Block

• Second-degree AV block (any type) with symptomatic bradycardia 2
• Type II second-degree AV block even when asymptomatic (Class II indication) 2, 1
• Advanced second-degree AV block persisting 10-14 days after cardiac surgery 2

Bifascicular and Trifascicular Block

• Bifascicular block with intermittent complete heart block and symptomatic bradycardia 3
• Bifascicular or trifascicular block with intermittent type II second-degree AV block 3
• External ophthalmoplegia with bifascicular blocks 2

Sinus Node Dysfunction

• Sinus node dysfunction with documented symptomatic bradycardia 2, 1
• Bradycardia-tachycardia syndrome requiring antiarrhythmic drugs other than digitalis or phenytoin 2
• Sinus node dysfunction with heart rates <40 beats/min and symptomatic bradycardia 2

Post-Myocardial Infarction

• Persistent advanced second-degree or complete heart block after MI 1
• Transient advanced AV block with associated bundle branch block after MI 1

Special Populations

• Congenital AV block with wide QRS escape rhythm or block below the His bundle 2
• Hypersensitive carotid sinus syndrome with syncope due to cardioinhibitory reflex 2
• Long QT syndrome with recurrent syncope or aborted sudden death refractory to beta-blockers 4

Class II Indications (Reasonable to Consider)

• Asymptomatic complete heart block with ventricular rates ≥40 beats/min 2, 1
• Asymptomatic type II second-degree AV block 2, 1
• Asymptomatic second or third-degree AV block with ventricular rate <45 beats/min when awake 2
• Complete AV block with ventricular rate <50 beats/min 2
• Sinus node dysfunction with heart rates <40 beats/min when clear association between symptoms and bradycardia has not been documented 2
• Bifascicular or trifascicular block with syncope not proven due to complete heart block 1, 3
• Markedly prolonged HV interval (>100 msec) found during electrophysiological study 3

Class III Indications (Not Recommended)

• First-degree AV block without symptoms 2
• Asymptomatic fascicular block without AV block 3
• Sinus node dysfunction in asymptomatic patients, even with heart rate <40 beats/min 2
• Transient AV block that returns to normal conduction within 1 week 2
• Asymptomatic congenital heart block without profound bradycardia 2
• Sinus node dysfunction when symptoms are clearly documented not to be associated with slow heart rate 2

Special Considerations

Pacing for Tachyarrhythmias

• Symptomatic recurrent supraventricular tachycardia when drugs fail or produce intolerable side effects 2
• Symptomatic recurrent ventricular tachycardia after implantation of an automatic defibrillator 2
• Recurrent supraventricular tachycardia as an alternative to drug therapy 2

Pacemaker Selection

• For patients with sick sinus syndrome without AV block, dual-chamber pacemakers are cost-effective compared to single-chamber atrial pacemakers 5
• Dual-chamber pacing reduces the risk of paroxysmal atrial fibrillation compared to single-chamber atrial pacing 5
• In bradycardia-tachycardia syndrome, pacing prevents drug-induced bradycardia and allows intensification of antiarrhythmic treatment 6

Important Clinical Pitfalls

• Sinus bradycardia in trained athletes (heart rates 40-50 beats/min while awake, 30-43 beats/min while sleeping) is physiologic and does not require pacing 2
• Temporary pacemakers can have serious complications (22% of patients), including electrode displacement (9%), femoral hematoma, cardiac tamponade, and even death (6%) 7
• Correlation of symptoms with specific arrhythmias is essential before pacemaker implantation, though this may be difficult due to the intermittent nature of episodes 2
• The decision to use a pacemaker to control tachycardias should be made only after careful observation 2
• In patients with complete heart block, symptoms must be presumed to be due to heart block unless proven otherwise 8