What are the indications for Permanent Pacemaker (PPM) insertion?

Indications for Permanent Pacemaker (PPM) Insertion

Permanent pacemaker implantation is definitively indicated for complete heart block or second-degree AV block with symptomatic bradycardia, sinus node dysfunction with documented symptomatic bradycardia, and persistent advanced AV block post-myocardial infarction with His-Purkinje system involvement. 1, 2

Classification System

The indications are stratified into three classes that guide clinical decision-making 1, 3, 2:

• Class I: General agreement that PPM should be implanted 1, 2
• Class II: Frequent use but divergence of opinion regarding necessity 1, 3
• Class III: General agreement that PPM is unnecessary 1, 2

Class I Indications (Definitive)

Complete Heart Block

PPM implantation is mandatory for complete heart block (permanent or intermittent, at any anatomic level) when associated with 1, 2:

• Symptomatic bradycardia (transient dizziness, light-headedness, syncope, cerebral ischemia, exercise intolerance, or congestive heart failure) - symptoms must be presumed due to heart block unless proven otherwise 1
• Congestive heart failure 1, 2
• Need for drugs that suppress escape pacemakers resulting in symptomatic bradycardia 1, 2
• Documented asystole ≥3.0 seconds or escape rate <40 bpm even in symptom-free patients 1
• Confusional states that clear with temporary pacing 1
• Post-AV junction ablation or myotonic dystrophy 1

Second-Degree AV Block

• Any type of second-degree AV block with symptomatic bradycardia (permanent or intermittent, regardless of type or site) 1, 2
• Asymptomatic type II second-degree AV block (permanent or intermittent) - this is a Class I indication even without symptoms due to high risk of progression 1, 2

Sinus Node Dysfunction

• Documented symptomatic bradycardia directly attributable to sinus node dysfunction 1, 3, 2
• The key requirement is documentation that symptoms occur simultaneously with bradycardia 1

Bifascicular and Trifascicular Block

• Intermittent complete heart block with symptomatic bradycardia 2
• Intermittent type II second-degree AV block even without symptoms 2

Post-Myocardial Infarction

• Persistent advanced second-degree or complete heart block with block in the His-Purkinje system (bilateral bundle branch block) 1, 2
• Transient advanced AV block with associated bundle branch block 1, 2
• Avoid early permanent pacing (<72 hours) to allow for recovery of conduction and prevent unnecessary implantation 1

Atrial Arrhythmias with AV Block

• Atrial fibrillation, atrial flutter, or supraventricular tachycardia with complete heart block or advanced AV block, bradycardia, and conditions listed under complete heart block - bradycardia must be unrelated to digitalis or AV-blocking drugs 1

Class II Indications (Reasonable but Controversial)

• Asymptomatic complete heart block with ventricular rates ≥40 bpm 1, 2
• Bifascicular or trifascicular block with syncope not proven due to complete heart block 2
• Markedly prolonged HV interval (>100 msec) on electrophysiology study 2

Class III Indications (NOT Indicated)

PPM implantation should not be performed for 1, 2:

• First-degree AV block alone without symptoms 1, 2
• Asymptomatic sinus bradycardia - common in athletes and during sleep with rates <40 bpm or pauses >5 seconds due to physiologic vagal tone 1
• Transient AV conduction disturbances without intraventricular conduction defects post-MI 1
• Transient AV block with isolated left anterior hemiblock 1
• Fascicular block without AV block or symptoms 2

Critical Considerations Before Implantation

Reversible Causes Must Be Excluded First

Always address reversible causes before proceeding to permanent pacing 1:

• Medications: Beta blockers, calcium channel blockers, digoxin, antiarrhythmics 1
• Metabolic abnormalities: Hypothyroidism, hyperkalemia, severe acidosis 1, 4
• Acute myocardial infarction: Allow adequate time for recovery of conduction 1

Risk-Benefit Analysis

PPM implantation carries 3-7% complication rates including infection, lead dislodgement, venous thrombosis, and death, with significant long-term lead management implications 1, 5:

• Avoid unnecessary implantation in asymptomatic patients or those with physiologic bradycardia 1
• Document symptom-rhythm correlation before proceeding in sinus node dysfunction 1
• Consider temporary pacing risks: Temporary transvenous pacing has higher infection rates (19.1% adverse events) compared to early permanent implantation 4

Common Pitfalls to Avoid

• Do not pace asymptomatic athletes or patients during sleep - bradycardia <40 bpm and pauses >5 seconds are physiologic 1
• Do not use atropine in infranodal conduction disease - it can worsen block and cause harm 1
• Do not implant PPM for symptoms without documented bradycardia - permanent pacing has no benefit 1
• Do not rush to permanent pacing post-MI - allow 72+ hours for conduction recovery when hemodynamically stable 1
• Weekend admissions delay PPM by 1 day and increase temporary pacing complications - consider early permanent implantation in high-risk patients 4

Device Selection Considerations

• Maintain AV synchrony when possible, especially in older patients, to preserve atrial contribution to ventricular filling 3
• Consider biventricular pacing (cardiac resynchronization therapy) for advanced heart failure with left bundle branch block 3, 2