Endothelial Dysfunction is a Marker of Systemic Response to the Cardiac Resynchronization Therapy in Heart Failure

Background: Cardiac resynchronization therapy (CRT) induces a significant improvement in patients with heart failure (HF), who are often characterized by the presence of endothelial dysfunction (ED) with impaired flow-mediated vasodilation (FMD). We aimed to study the ED in patients with BF candidates to CRT with defibrillator (CRT-D). Methods and Results: We studied 57 consecutive patients affected by HF and undergoing CRT-D. At the baseline we recorded a high prevalence of ED (64.9%) with impaired FMD (4.1 +/- 3.8%). After 12 months of CRT, we reported a marked increase of the mean FMD (8.8 +/- 4.8% vs 4.1 +/- 3.8%; P < .05) along with significant improvement of left ventricular ejection fraction (LVEF), left ventricular end-systolic volume (LVESV), New York Heart Association (NYHA) functional class, and 6-minute walk test (6MWT); 42 patients (73.7%) were classified as responders according to standard criteria. FMD was related to LVEF (r = 0.169; P < .05), LVESV (r = 0.169; P < .05), NYHA functional class (r = 0.27; P < .051), and 6MWT (r = 0.360; P < .01). Conclusions: ED is not an independent predictor of CRT response, but it is able to intercept the systemic effects of CRT and is an affordable marker of response to CRT, especially in patients unable to perform the 6MWT.