Baseline QRS width and mitral regurgitation behavior after cardiac resynchronization therapy among patients with dilated cardiomyopathy

BackgroundThe effect of cardiac resynchronization therapy (CRT) on functional mitral regurgitation (FMR) is reflected on both clinical and echocardiographic response. We sought to assess the behavior of FMR and the response to CRT implantation in relation to the baseline width of the QRS complex among patients with dilated cardiomyopathy (DCM).Patients and methodsThis is a prospective observational case-control study, including forty patients with advanced DCM who had left bundle branch block (LBBB), QRS ⩾ 130 ms (group 1) and 10 patients with QRS < 130 ms (group 2) both with echocardiographic evidence of dyssynchrony and subjected to CRT in our center.ResultsEvidence of response to CRT at 6 months, was observed in 31 patients (77.5%) of group 1 Vs 2 (20%) patients of group 2 (p. 0.001). MR improvement was higher among responders to CRT in 31/33 (93.9%) Vs 2/17 patients (11.7%) of the non responders (p. 0.003). FMR improvement was observed in 31 patients of group 1 (77.5%) Vs 2 patients of group 2 (20%) p. value 0.001.ConclusionAmong patients with DCM, the degree of FMR regression after CRT seems to be more clear in patients with a baseline QRS width ⩾130 ms and this seems to be associated with better response of the patients to CRT.