Cardiac resynchronization therapy may benefit patients with left ventricular ejection fraction >35: A PROSPECT trial substudy

Abstract

Aims Cardiac resynchronization therapy (CRT) is currently limited to those with left ventricular ejection fraction (LVEF) ≤35. To evaluate whether patients with LVEF >35 might benefit from CRT, we performed a retrospective analysis of the predictors of response to CRT (PROSPECT) database. Methods and results PROSPECT was a prospective, multicentre study that enrolled CRT patients based on enrolling centre-evaluated LVEF <35, but all echocardiograms were subsequently analysed by a core laboratory. Patients with core laboratory-measured LVEF >35 (OVER35) were compared with those whose LVEF was <35 (UNDER35). Clinical composite score (CCS) and change in LV end systolic volume (LVESV) were analysed from baseline to 6-month follow-up. Of 361 patients, 86 (24) had LVEF >35. At entry, OVER35 had smaller LV volumes, shorter QRS duration, shorter 6-min walk distance, and were more likely to have ischaemic aetiology than UNDER35. Outcomes were comparable between the groups, with 62.8 of OVER35 improved in CCS (70.2 in UNDER35) and 50.8 of OVER35 improved in LVESV (57.8 in UNDER35). Conclusion Patients with LVEF >35, New York heart association functional Class III-IV status, and QRS >130 ms appear to derive clinical and structural benefit from CRT. As CRT may offer a valuable option for these patients, this hypothesis should be formally tested in a prospective, randomized multicentre trial. © 2010 The Author.