What are the definite causes for pacemaker (artificial heart rhythm regulator) placement?

Definite Causes for Pacemaker Placement

Permanent pacemaker implantation is definitively indicated for complete heart block with symptomatic bradycardia, congestive heart failure, or medical conditions requiring drugs that suppress escape pacemakers. 1, 2

Class I Indications (Definite Causes)

Acquired AV Block in Adults

• Complete heart block (permanent or intermittent) at any anatomic level with:

  • Symptomatic bradycardia (dizziness, light-headedness, syncope, exercise intolerance, heart failure) 1
  • Congestive heart failure 1
  • Medical conditions requiring drugs that suppress escape pacemakers 1
  • Documented asystole ≥3.0 seconds or escape rate <40 beats/min 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 (permanent or intermittent) with symptomatic bradycardia, regardless of type or site of block 1

• Atrial fibrillation, atrial flutter, or supraventricular tachycardia with complete heart block or advanced AV block and bradycardia (unrelated to digitalis or drugs known to impair AV conduction) 1

AV Block Associated with Myocardial Infarction

• Persistent advanced second degree AV block or complete heart block after acute myocardial infarction with block in the His-Purkinje system 1
• Transient advanced AV block with associated bundle branch block 1

Sinus Node Dysfunction

• Sinus node dysfunction with documented symptomatic bradycardia 1, 2
• Bradycardia-tachycardia syndrome requiring antiarrhythmic drugs other than digitalis 1

Pediatric Indications

• Second or third degree AV block with symptomatic bradycardia 1
• Advanced second or third degree AV block with moderate to marked exercise intolerance 1
• External ophthalmoplegia with bifascicular block 1
• Congenital AV block with wide QRS escape rhythm or block below the His bundle 1
• Advanced second or third degree AV block persisting 10-14 days after cardiac surgery 1

Hypersensitive Carotid Sinus Syndrome

• Pure excessive cardioinhibitory response to carotid stimulation causing symptomatic bradycardia 1

Class II Indications (Frequently Used)

• Asymptomatic complete heart block with ventricular rates ≥40 beats/min 1, 2
• Asymptomatic type II second degree AV block 1, 2
• Bifascicular or trifascicular block with syncope not proven due to complete heart block 2
• Markedly prolonged HV interval (>100 msec) 2

Advanced Heart Failure

• Biventricular pacing (cardiac resynchronization therapy) for advanced heart failure with major intraventricular conduction defects, predominantly left bundle branch block 1, 2

Contraindications for Pacemaker Placement

• First degree AV block without symptoms 1, 2
• Fascicular block without AV block or symptoms 2
• Transient AV conduction disturbances without intraventricular conduction defects 2
• Sinus node dysfunction in asymptomatic patients 2

Clinical Considerations

• The decision to implant a pacemaker should prioritize symptoms directly attributable to bradycardia 1
• Patients with complete heart block and syncope have improved survival with permanent pacing 1
• Type II second degree AV block may be a precursor to complete AV block and should be treated with a permanent pacemaker even in asymptomatic patients, particularly if associated with fascicular block 1
• In elderly patients, devices that maintain synchrony between atria and ventricles are preferred to maintain the atrial contribution to ventricular filling 1
• Rate-responsive devices are generally preferred as they better simulate physiologic function of the sinus node 1

Common Pitfalls and Caveats

• Physiologic sinus bradycardia in highly trained athletes should not be confused with pathologic bradyarrhythmias requiring pacing 1
• The requirement for temporary pacing in acute myocardial infarction does not by itself constitute an indication for permanent pacing 1
• In hypersensitive carotid sinus syndrome, it's essential to define the vasodepressor component before concluding all symptoms are related to asystole alone, as 10-20% of patients have both cardioinhibitory and vasodepressor components 1
• The absence of documented symptomatic bradycardia should not rule out permanent pacing for symptomatic patients in any diagnostic group, as this criterion has low specificity (71%) for predicting poor outcomes after pacing 3