antitachy

Antitachycardia pacing (ATP) is a pacing therapy delivered by implantable devices such as implantable cardioverter-defibrillators (ICDs) and some pacemakers to terminate tachyarrhythmias, most commonly monomorphic ventricular tachycardia. Unlike shocks, ATP uses a sequence of rapid paced impulses designed to interrupt the reentrant circuit causing the tachycardia, potentially restoring a normal rhythm with less patient discomfort and lower energy use.

ATP is delivered after tachycardia is detected and is typically applied in designated therapy zones. The pacing can be implemented as bursts, with a fixed number of pulses at a rate slightly faster than the tachycardia, or as ramps, where the interval between pulses shortens progressively. Some devices may employ multisite pacing or adjusted timing to optimize success depending on the suspected mechanism of the tachycardia.

Effectiveness varies: ATP terminates many episodes of stable, monomorphic VT and can significantly reduce the number of shocks a patient receives, improving quality of life and device longevity. However, ATP is not effective for all tachyarrhythmias; it may be ineffective for polymorphic VT or atrial tachyarrhythmias, and in some cases can paradoxically accelerate a tachycardia or precipitate hemodynamic compromise if the patient is unstable.

In practice, ATP is part of a broader strategy for arrhythmia management, often used in conjunction with other therapies and tailored to individual patient physiology. Some devices also offer atrial antitachycardia pacing options to address rapid atrial tachycardias with minimal symptoms.