Long-term outcome of patients with and without super-response to CRT-D.

OBJECTIVE: To compare outcome between patients with and without super-response to cardiac resynchronization therapy-defibrillator (CRT-D). METHODS AND
RESULTS: In this cohort study, 167 consecutive CRT-D candidates were included. Super-response to CRT-D was defined clinically [improvement of ≥1 New York Heart Association (NYHA) class or ≥50 m in six-minute walk distance (6MWD)] and echocardiographically [increase of left ventricular ejection fraction (LVEF) ≥1 category (LVEF <30 to 30-40 % or 30-40 to 41-51 %) or reduction of left ventricular end-diastolic diameter (LVEDD) ≥10 mm]. Clinical outcome (death, cardiac transplantation and appropriate shock therapy) was compared between super-responders (n = 32) and non-super-responders (n = 135). During follow-up (616 patient-years; median 3.3 years), all-cause mortality was significantly lower in super-responders compared to non-super-responders (log rank p < 0.05). At least one appropriate shock was noted in 22 % of super-responders and 39 % of non-super-responders (p = 0.069). Time to appropriate shock therapy was significantly longer in super-responders (log rank p < 0.05). Event-free survival from death or cardiac transplantation was comparable between the two groups.
CONCLUSION: Super-response to CRT-D is associated with improved survival and lower risk of appropriate shock therapy compared to non-super-responders. Further information about the mechanisms of super-response and its long-term consequences are needed to foresee favorable outcome after implantation of CRT-D.