Responders to Cardiac Resynchronization Therapy with Narrow or Intermediate QRS Complexes Identified by Simple Echocardiographic Indices of Dyssynchrony: The DESIRE Study

BACKGROUND: Cardiac resynchronization therapy (CRT) is recommended for patients with NYHA class III-IV refractory heart failure (HF), ejection fraction 120 ms. We attempted to identify responders to CRT from echocardiographic (echo) indices of mechanical dyssynchrony in patients with QRS or =1 echo criterion of mechanical dyssynchrony (DES+ group) and 33 had no evidence of dyssynchrony (DES- group). At 12 months, 8 patients (4 per group) had died, 7 from HF. As regards the primary endpoint at 6 months, 33 patients (55%) had improved, 10 (16%) were unchanged, and 17 (29%) had deteriorated. Clinical improvement was observed in 19 of 27 DES+ (70%), versus 14 of 33 DES- (42%) patients (P<0.04). Baseline QRS duration did not predict response to CRT. CONCLUSIONS: In this population of HF patients with QRS<150 ms, the presence of mechanical dyssynchrony at baseline D-echo examination, but not the QRS width, predicted 6-month clinical response to CRT.