Abstract 3243: Cardiac Resynchronization Therapy: Characteristics of Hyperresponders
Background Cardiac resynchronization therapy (CRT) is a recognized treatment modality for patients with heart failure (HF). Interestingly, some patients treated with CRT have a marked improvement in ejection fraction (EF) and functional capacity within 6 months and thus can be considered “hyperresponders”.
Objective The purpose of this study was to investigate the characteristics of “hyperresponders” versus others who show some or no improvement.
Methods 208 consecutive HF patients who underwent CRT were analyzed retrospectively. Patients were considered to be “hyperresponders” if they fulfilled 2 criteria at 6 months post CRT: Improvement in NYHA by at least one class and absolute improvement in EF by ≥20% EF Unit%. Patients were considered “non-responders” if they had less than 5% improvement in EF and no improvement in NYHA class. Rest of the patients had intermediate improvement and were called “Responders”.
Results Out of 208 patients, 21 (10%) were hyperresponders (EF increased from 25%±8% to 55%±5%, P=.005), 187 (52%) were responders (25%±5% to 32±5%, P=0.01) and 79 (38%) non responders (25%±5% to 20±8%, P=NS). Comparison of baseline parameters between hyperresponders and others (Responders + Non responders) is shown in the table⇓ below. Hyperresponders when compared to others were more likely to have the following characteristics: preexisting left bundle branch block (LBBB) morphology on EKG (p=0.037), non ischemic etiology (p=0.02), and normal renal function with glomerular filtration rate (GFR) ≥60 ml/min by MDRD method (P=0.015). Further comparison of hyperresponders to non-responders (not shown in table⇓) showed similar but more pronounced differences: preexisting LBBB (p=0.002), non ischemic etiology (p=0.01), and normal renal function (P=0.01).
Conclusion In this study, the presence of LBBB, non ischemic etiology and normal renal function were found to be predictors for hyperresponse to CRT in terms of marked improvement in EF and NYHA class.