Predictors of responders to cardiac resynchronization therapy in patients with non-left bundle branch block with mid-wide QRS duration

Abstract

Abstract Background Cardiac resynchronization therapy (CRT) is useful for patients with severe heart failure with dyssynchrony of left ventricular contraction, significantly reducing total mortality or heart failure rehospitalization. In patient with left bundle branch block (LBBB) or QRS duration (QRSd) ≥ 150 ms, CRT is a well-established therapy at guidelines in Japan and other countries. However, CRT may be more useful and effective in Asian patients with middle range wide QRSd, because of smaller body size than in the West. Few reports have shown the usefulness and efficacy of CRT in patients with non-LBBB and middle range wide QRS duration (mid-wide QRSd). Purpose To evaluate the predictors of CRT responders in heart failure patients with non LBBB and mid wide QRSd. Methods We retrospectively studied 174 consecutive patients who underwent a denovo CRT device implantation at two institutions between September 2013 and March 2023. Follow up echocardiography examination could be performed after 150 days postoperatively. CRT responders were defined as a decrease in left ventricular end systolic volume ≥15% on echocardiography. We plotted thereceiver operating characteristic (ROC) curve for predicting CRT responders. The area under the curve (AUC) was calculated to determine the best cut off value. Results A total of 34 patients with non LBBB and 120≤ QRSd <150 ms were enrolled in this study. Sixteen of 34 (47%) patients were the responders for CRT. There was no significant difference in gender between the responder and non responder groups (p=0.274). Non ischemic cardiomyopathy was more prevalent in the responder group (p=0.046). The ROC curve analysis confirmed that 0.809 was the better optimal cut off value of QRSd/left ventricular end diastolic volume (LVEDV) for predicting CRT responders (AUC = 0.688). The multivariate analysis demonstrated that QRSd/LVEDV was significantly associated with CRT responders [odds ratio (OR) 9.88, 95% confidence interval 1.51 64.90, p = 0.017]. Conclusion The corrected QRSd for heart size using LVEDV could be the independent predictor of CRT responders in Japanese patients with non LBBB and mid wide QRSd.