Prognostic role of coronary flow reserve for left ventricular functional improvement after cardiac resynchronization therapy in patients with dilated cardiomyopathy

Abstract

Aims The aim of the study wasto assess the value of coronaryflowreserve (CFR) for predicting improvement of left ventricular function after cardiac resynchronization therapy (CRT). Methods and results Study population included 40 patients (mean age 58+9 years) with heart failure (ejection fraction 25, 7+5, 4%) and QRS duration of 158+22 ms, planned for CRT. Before and after CRT implantation, CFR was measured non-invasively during hyperaemia induced with adenosine. Responders were defined by decrease in end-systolic volume ≥15%. Followup echocardiography and CFR measurements were obtained after 6 months. At baseline there was no significant difference in left ventricular ejection fraction (LVEF), QRS duration, 6 min walk test distance and coronary flowvelocity at rest betweenresponder (n = 26) vs. non-responder group (n = 14, P = ns). BeforeCRTimplantation, responders compared with non-responders, showed a greater increase in coronary flow velocity during hyperaemia, and consequently higher CFR: 2.41+0.60 vs. 1.61+0.45 (P = 0.001). There was significant correlation between CFR before CRT implantation and LVEFafter 6 months (r = 0.545, P = 0.001). End-diastolic, end-systolic left ventricular diameter, andCFRbeforeCRT were predictors of LVfunctional improvement. By multivariate analysis, onlyCFRbeforeCRTwas independent predictor of left ventricular recovery in the follow-up period (P = 0.001). Conclusion Our results demonstrate that preserved CFR in patients with dilated cardiomyopathy is predictive of left ventricular improvement after CRT implantation. © The Author 2014.