Long-term outcome of super-responder patients to cardiac resynchronization therapy

To evaluate the long-term changes of clinical and echocardiographic parameters, the incidence of cardiac events and parameters associated with late cardiac events in super-responders to cardiac resynchronization therapy (CRT) with [CRT defibrillator (CRT-D)] or without defibrillator back-up. In all consecutive patients treated with CRT in two Italian centres (Trieste and Udine) with left ventricular ejection fraction (LVEF) 0.35 at implantation (T-imp) and LVEF 0.50 1 and/or 2 years (T-norm) after implantation, the long-term outcome and the evolution of echocardiographic parameters were assessed; factors associated with a higher risk of cardiac events, defined as hospitalization or death for heart failure (HF), sudden death, or CRT-D appropriate interventions, were also analysed. Among the 259 patients evaluated, 62 (24) had LVEF 0.50 at T-norm (n 44 with at 1 year, n 18 at 2 years). During a mean follow-up of 68 30 months, one cardiac death (for HF) and eight cardiovascular events (two hospitalization for HF and six appropriate CRT-D interventions) occurred. At the last echo evaluation (T-fup) performed 51 26 months after T-imp, LVEF was 0.50 in five patients (0.45 in four of them). At univariable analysis, only LV end-systolic volume evaluated at T-fup was associated with a higher risk of cardiac events during follow-up. In super-responders to CRT long-term outcome is excellent. However, cardiac events, mainly CRT-D appropriate interventions, can occur despite the persistence of LVEF 0.50. Early identification of these patients is still an unsolved issue.