Active Arrhythmia Pattern: A Novel Predictor of ICD Shocks-A Subanalysis From the PARTITA Study

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• Antitachycardia pacing (ATP) can predict implantable cardioverter defibrillator (ICD) shocks.
• Catheter ablation post-ICD shock reduces mortality and heart failure progression.
• Optimal ATP threshold for pre-emptive ablation remains undefined.

Purpose of the Study:

• To identify an ATP threshold and clinical factors predicting ICD shocks and cardiovascular events.
• To stratify patients based on arrhythmia patterns and clinical data for risk assessment.

Main Methods:

• Analysis of 517 patients from the PARTITA study (Phase A).
• Utilized classification and regression tree analysis for risk model development and validation.
• Secondary endpoints included worsening heart failure and cardiovascular hospitalization.

Main Results:

• An active arrhythmia pattern (≥5 ATPs in 6 months) identified patients at highest risk for ICD shocks (93% training, 86% testing).
• Low risk observed in patients without ATPs (1% training, 2% testing).
• Left ventricular ejection fraction <35%, age <60, and obesity were additional predictors. Active arrhythmia pattern significantly increased risk for heart failure and cardiovascular hospitalizations.

Conclusions:

• An active arrhythmia pattern (≥5 ATPs/6 months) signifies elevated risk for ICD shocks, heart failure, and cardiovascular hospitalizations.
• Preventive strategies, potentially including early ventricular tachycardia ablation, may benefit this high-risk group.
• Prospective randomized trials are necessary to validate the benefits of early ablation.