Can pacemakers (permanent artificial cardiac pacing devices) prevent ventricular tachycardia (VTach) in patients with a history of life-threatening arrhythmias?

Pacemakers Do Not Prevent Ventricular Tachycardia in Most Cases

Standard pacemakers are not effective for preventing ventricular tachycardia in the vast majority of patients, and serious or symptomatic ventricular arrhythmias are rarely prevented by pacing alone. 1 The primary exception is the specific subset of patients with long QT syndrome who have pause-dependent ventricular tachycardia, where continuous pacing combined with beta blockade may provide benefit. 1

Key Distinctions in Pacemaker Therapy for VTach

Termination vs. Prevention

Pacemakers can serve two distinct roles that must not be confused:

• Termination of VTach: Antitachycardia pacing (ATP) can terminate certain reentrant ventricular tachycardias through programmed stimulation or rapid pacing bursts 1
• Prevention of VTach: Pacing to prevent VTach occurrence is effective only in highly specific circumstances 1

When Pacemakers Are NOT Appropriate for VTach Prevention

The ACC/AHA guidelines explicitly classify as Class III (not indicated) the use of pacemakers for:

• Frequent or complex ventricular ectopic activity without sustained VTach in patients with coronary artery disease, cardiomyopathy, mitral valve prolapse, or normal hearts 1
• General prevention of life-threatening ventricular arrhythmias—pacemakers are not effective in preventing or treating life-threatening ventricular arrhythmias 1

The Specific Exception: Long QT Syndrome

Pacemakers receive a Class II indication (reasonable to consider) for long QT syndrome when combined with beta blockade. 1

• Continuous pacing prevents pause-dependent ventricular tachycardia in long QT patients 1
• The combination of pacing and beta blockade shortens the QT interval and helps prevent sudden cardiac death 1
• ICD therapy with overdrive suppression pacing should be considered in high-risk long QT patients 1

The Appropriate Device for Life-Threatening VTach

For patients with life-threatening ventricular arrhythmias, an implantable cardioverter-defibrillator (ICD) is the appropriate device, not a standard pacemaker. 1

• Permanent antitachycardia pacing as monotherapy for VTach is not appropriate 1
• ATP algorithms are now incorporated into tiered-therapy ICDs that provide cardioversion and defibrillation when ATP fails or causes acceleration 1
• ICDs effectively prevent sudden cardiac death in patients at risk for life-threatening ventricular tachyarrhythmias 1

Limited Role for Antitachycardia Pacing

When pacemakers are used for VTach, it is only as an adjunct after ICD implantation:

• Class I indication: Symptomatic recurrent VTach after an automatic defibrillator has been implanted when VTach recurrence is not prevented by drug therapy or when no other therapy is applicable 1
• Class II indication: Sustained VTach when all other therapies are ineffective or inapplicable and efficacy of pacing is thoroughly documented 1

Critical Safety Concerns

Risk of Proarrhythmia

• Pacemakers can accelerate tachycardia or convert it to ventricular fibrillation 1
• Tachycardias that are accelerated or converted to fibrillation by pacing are a Class III contraindication 1
• Extensive electrophysiologic testing is mandatory before implantation to ensure safe termination without acceleration 1

Patient Selection Requirements

• Patients must have failed or be intolerant of antiarrhythmic drugs 1
• The decision requires careful observation and electrophysiologic study by experienced specialists 1
• Efficacy of pacing must be thoroughly documented before implantation 1

Clinical Bottom Line

For the typical patient with life-threatening ventricular arrhythmias, refer for ICD evaluation, not pacemaker implantation. 1 Pacemakers alone do not prevent VTach except in the narrow context of pause-dependent arrhythmias in long QT syndrome, and even then should be combined with beta blockade and consideration of ICD therapy. 1