Results of the SCART study: selection of candidates for cardiac resynchronisation therapy

Abstract

To prospectively determine whether prespecified electrocardiographic, echocardiographic and tissue Doppler imaging (TDI) selection criteria may predict a positive response to cardiac resynchronisation therapy (CRT). In this multicentre, prospective, non-randomised study, 96 heart failure patients with New York Heart Association class III–IV symptoms, an ejection fraction of ≤35%, and at least one marker of ventricular dyssynchrony according to prespecified electrocardiographic, echocardiographic or TDI criteria were enrolled. The primary endpoint was an improvement in the clinical composite score at 6 months. At enrolment, 70 patients fulfilled the electrocardiographic criterion (QRS duration ≥150 ms), 77 patients showed echocardiographic signs of dyssynchrony, and 37 patients met the TDI dyssynchrony criteria. The overall responder rate was 78/96 (81%). In particular, the primary endpoint was reached in 68 patients who fulfilled the echocardiographic criteria as compared with 10 patients who did not (88 vs. 53%, P = 0.001). The patients who met the echocardiographic criteria showed a significant greater reduction in left ventricular end-systolic diameter (P = 0.029) and a higher improvement in quality of life (P = 0.017) than patients who did not. Neither electrocardiographic nor TDI criteria seemed to predict a positive response to CRT. In our patient population, mechanical indexes of dyssynchrony as assessed by echocardiography appeared to identify CRT responders. Although TDI is useful for evaluating ventricular dyssynchrony after CRT, the prespecified TDI inclusion criteria adopted in this investigation did not increase the number of CRT responders.