Pacemaker Indications and Pacing Mode Recommendations (Evidence‑Based)

1. Definitive (Class I) Indications for Permanent Pacemaker Implantation

Advanced second‑ or third‑degree atrioventricular (AV) block that is associated with ventricular dysfunction or low cardiac output warrants permanent pacing. American Heart Association/American College of Cardiology recommendation. 1
In sinus node dysfunction, implantation is indicated when symptomatic bradycardia is documented on ambulatory monitoring or an implantable loop recorder and the symptoms (syncope, presyncope, dizziness) occur simultaneously with the bradyarrhythmia. American Heart Association/American College of Cardiology recommendation. 1
Pediatric patients with advanced second‑ or third‑degree AV block who exhibit moderate to marked exercise intolerance should receive a pacemaker. American College of Cardiology recommendation. 2
Congenital AV block accompanied by a wide‑QRS escape rhythm or block distal to the His bundle is an indication for pacing in children. American College of Cardiology recommendation. 2
Persistent advanced AV block lasting 10–14 days after cardiac surgery in pediatric patients is an indication for permanent pacing. American College of Cardiology recommendation. 2

A heart rate of 45 bpm may be physiologically normal in an adolescent but represents profound bradycardia in a newborn; age‑specific thresholds must be applied when deciding on pacing. American Heart Association/American College of Cardiology guidance. 1
Before attributing symptoms to intrinsic conduction disease, reversible causes (e.g., medications, electrolyte disturbances, sleep‑apnea, neurocardiogenic mechanisms, seizures) must be excluded. American Heart Association/American College of Cardiology guidance. 1

Pacing is contraindicated for tachyarrhythmias that are accelerated or converted to fibrillation by pacing. American College of Cardiology contraindication. 2

Dual‑chamber pacing is preferred in older patients to preserve AV synchrony and maintain atrial contribution to ventricular filling. American Heart Association/American College of Cardiology recommendation. 3
Ventricular‑only (VVI) pacing should be avoided when it induces pacemaker syndrome (loss of AV synchrony causing symptoms). American Heart Association/American College of Cardiology recommendation. 3
For sinus node dysfunction with intact AV conduction, atrial‑only pacing (AAI mode) is appropriate. American Heart Association/American College of Cardiology recommendation. 3

The American College of Cardiology recommends pacemaker implantation for complete heart block with symptomatic bradycardia, congestive heart failure, or medical conditions requiring drugs that suppress escape pacemakers 4, 5
The American Heart Association suggests pacemaker implantation for second degree AV block with symptomatic bradycardia, and for type II second degree AV block even when asymptomatic 5
The American College of Cardiology recommends pacemaker implantation for bifascicular block with intermittent complete heart block and symptomatic bradycardia, and for bifascicular or trifascicular block with intermittent type II second-degree AV block without symptoms 4
The American Heart Association suggests pacemaker implantation for sinus node dysfunction with documented symptomatic bradycardia 4, 6
The American College of Cardiology recommends pacemaker implantation for post-myocardial infarction patients with persistent advanced second degree or complete heart block, or with transient advanced AV block and associated bundle branch block 5

The American College of Cardiology suggests pacemaker implantation for asymptomatic complete heart block with ventricular rates ≥40 beats/min, and for asymptomatic type II second degree AV block 4, 5
The American Heart Association suggests pacemaker implantation for bifascicular or trifascicular block with syncope not proven due to complete heart block, and for markedly prolonged HV interval (>100 msec) 4

The American Academy of Pediatrics recommends pacemaker implantation for pediatric patients with second or third degree AV block and symptomatic bradycardia, or with advanced second or third degree AV block and exercise intolerance 7
The American College of Cardiology suggests pacemaker implantation for patients with symptomatic recurrent supraventricular tachycardia or ventricular tachycardia when other therapies are not applicable 7
The American Heart Association recommends biventricular pacing for advanced heart failure with major intraventricular conduction defects, predominantly left bundle branch block 8, 6

The American College of Cardiology recommends against pacemaker implantation for first degree AV block without symptoms, fascicular block without AV block or symptoms, and transient AV conduction disturbances without intraventricular conduction defects 4, 5
The American Heart Association recommends against pacemaker implantation for sinus node dysfunction in asymptomatic patients, and for tachycardias that are accelerated or converted to fibrillation by pacing 4, 7