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 <35% and a QRS >120 ms. We attempted to identify responders to CRT from echocardiographic (echo) indices of mechanical dyssynchrony in patients with QRS < 150 ms. Methods and results: The study enrolled 51 men and 9 women (mean age: 64.5 years) in NYHA class III (n = 54) or IV (n = 6) presenting with a mean ejection fraction: 25.7%, LV end-diastolic diameter: 69.1 mm, and QRS = 121 19 ins. All patients were implanted with a CRT system and followed for I year. Implantation was preceded and followed by clinical, functional and Doppler (D)-echo evaluation. The primary combined endpoint included 1) death from any cause, 2) HF-related hospitalisations, and 3) NYHA class at 6 months. Before implant, 27 patients had >= 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 HE As regards the primary endpoint at 6 months, 33 patients (55%) bad 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. (C) 2008 Published by Elsevier B.V. on behalf of European Society of Cardiology.