Association between changes in QRS width and echocardiographic responses to cardiac resynchronization therapy: A systematic review and meta-analysis

BACKGROUND: Numerous studies have illustrated the association of QRS width with the incidence of echocardiographic response to cardiac resynchronization therapy (CRT). This study aimed to summarize the observational studies regarding the magnitude of change in QRS width between responders and nonresponders to CRT. METHODS: The PubMed, Embase, and the Cochrane Library were systematically searched for relevant studies investigating the changes of QRS width with the incidence of echocardiographic response to CRT from inception till May 2019. The pooled weighted mean difference (WMD) with 95% confidence interval (CI) was calculated through random-effects model. RESULTS: Five prospective and 6 retrospective studies with a total of 1524 patients were selected for final analysis. The reduction of QRS width in responders was significantly greater than nonresponders (WMD: –20.54 ms; 95% CI: –26.78 to –14.29; P < .001). Moreover, responders were associated with greater percentage reduction in QRS width when compared with nonresponders (WMD: –8.80%; 95% CI: –13.08 to –4.52; P < .001). Finally, the mean change in QRS width between responders and nonresponders differed when stratified by country, study design, mean age, percentage male, ejection fraction, measuring time of postimplanted QRS, ischemic cardiomyopathy, atrial fibrillation, and study quality. CONCLUSIONS: These findings indicated that shortening QRS width after CRT device implantation showed association with greater incidence of echocardiographic responses to CRT. Further prospective studies should be conducted to evaluate the prognostic values of QRS width on the incidence of echocardiographic response to CRT.