Predicting hyperresponse among pacemaker-dependent nonischemic cardiomyopathy patients upgraded to cardiac...

Area of Science:

• Cardiology
• Electrophysiology
• Heart Failure Management

Background:

• Right ventricular (RV) pacing can lead to left ventricular (LV) dysfunction, adverse remodeling, and heart failure (HF).
• Cardiac resynchronization therapy (CRT) may reverse these negative effects in pacemaker-dependent patients.

Purpose of the Study:

• To identify clinical characteristics predicting hyperresponse (normalized LV function) after CRT upgrade in RV-paced patients.
• To assess long-term outcomes of hyperresponders versus non-hyperresponders.

Main Methods:

• Retrospective analysis of 51 RV-paced patients with LV ejection fraction (EF) ≤ 35% upgraded to CRT-defibrillators (CRT-D).
• Echocardiography before and after CRT to assess LV function and dimensions.
• Clinical outcomes including mortality, transplant, mechanical support, and HF hospitalizations were tracked.

Main Results:

• Fifteen patients (29%) were identified as hyperresponders (LVEF ≥ 50%).
• Hyperresponders had smaller baseline LV end-systolic (<48 mm) and end-diastolic (<58 mm) dimensions, and shorter cardiomyopathy duration (<24 months).
• Hyperresponders demonstrated significantly better long-term survival and fewer adverse cardiac events compared to non-hyperresponders.

Conclusions:

• Smaller baseline LV dimensions and shorter cardiomyopathy duration are key predictors of hyperresponse to CRT in RV-paced patients.
• Patients achieving hyperresponse with CRT experience excellent long-term clinical outcomes.