What is antitachycardia pacing (ATP)?

From the Guidelines

Antitachycardia pacing (ATP) is a highly effective therapy for terminating ventricular tachycardia, with a success rate of 80-90% for slow to moderate ventricular tachycardias, and should be programmed to attempt termination of ventricular tachycardias in the range of 150-200 beats per minute before delivering a shock, as it can significantly improve patient quality of life by reducing the need for painful shocks 1.

Key Points

• ATP works by delivering a series of rapid electrical impulses at a rate faster than the tachycardia, which interrupts the reentrant circuit causing the arrhythmia and allows the heart to return to normal rhythm.
• Most modern devices are programmed to deliver 8-12 pacing stimuli at 88-91% of the tachycardia cycle length (slightly faster than the tachycardia), with options for multiple attempts and different pacing patterns such as burst, ramp, or scan.
• The main advantage of ATP is that it can terminate arrhythmias without the psychological trauma and pain associated with ICD shocks, significantly improving patient quality of life.
• However, ATP is not effective for very fast ventricular tachycardias or ventricular fibrillation, which require immediate shock therapy.

Considerations

• The optimal management of cardiac pacing in ICD patients in whom bradycardia support is required, desired, or emerges is unknown, and efforts to optimize pacing mode or site should be greater in patients with longer expected duration of pacing, poorer cardiac function, and larger mechanical asynchrony 1.
• Awareness of the problem of dyssynchrony should also lead to more regular monitoring of cardiac ventricular systolic function and mechanical asynchrony in any patient with ventricular pacing.
• Any hardware system that increases unnecessary ventricular pacing from any site may increase the risk of heart failure, particularly in patients with poor cardiac ventricular systolic function 1.

From the Research

Antitachycardia Pacing Overview

• Antitachycardia pacing is a treatment used to terminate ventricular tachycardias, with a success rate of 80-90% in patients with implantable cardiac-defibrillators (ICD) 2.
• The algorithm used for termination seems to be of less importance, with respect to both efficacy and safety 2.
• Antitachycardia pacing should be considered for patients with spontaneous monomorphic ventricular tachycardia, even if they are noninducible 2.

Efficacy and Safety

• The adjusted ATP success rate was 63% for fast ventricular tachycardias and 68% for ventricular tachycardias in patients with a cardiac resynchronization therapy defibrillator 3.
• Acceleration occurred in 1.87% and syncope in 0.14% of all ATP-treated episodes 3.
• Antitachycardia pacing displayed a good safety profile, with no increase in death risk due to the therapy itself 3.

Comparison with Other Treatments

• Synchronized cardioversion is first-line management for hemodynamically unstable patients with supraventricular tachycardia, while vagal maneuvers are first-line management for hemodynamically stable patients 4, 5.
• Catheter ablation has a high success rate and is recommended as the first-line method for long-term management of recurrent, symptomatic paroxysmal supraventricular tachycardia 4, 5.

Specific Patient Populations

• Antitachycardia pacing can be effective in patients with heart failure implanted with a cardiac resynchronization therapy defibrillator device 3.
• Patients with Wolff-Parkinson-White syndrome may benefit from catheter ablation, which has a success rate of 95% and a recurrence rate of less than 5% 5.