Karaca, O?uzOmaygenç, Mehmet OnurÇakal, BeytullahÇakal, Sinem DenizGüneş, Hacı MuratBarutçu, İrfanBoztosun, BilalKılıçaslan, Fethi10.07.20192019-07-1010.07.20192019-07-102016Karaca, O., Omaygenç, M., Çakal, B., Çakal, S., Barutçu, İ., Boztosun, B. ... Kılıçaslan, F. (2016). Effect of QRS narrowing after cardiac resynchronization therapy on functional mitral regurgitation. American Journal of Cardiology, 117(3), 412-419. https://dx.doi.org/10.1016/j.amjcard.2015.11.0100002-9149https://hdl.handle.net/20.500.12511/749https://dx.doi.org/10.1016/j.amjcard.2015.11.010The determinants of improvement in functional mitral regurgitation (FMR) after cardiac resynchronization therapy (CRT) remain unclear. We evaluated the predictors of FMR improvement and hypothesized that CRT-induced change in QRS duration (?QRS) might have an impact on FMR response after CRT. One hundred ten CRT recipients were enrolled. CRT response (?15 reduction in left ventricular end-systolic volume) and FMR response (absolute reduction in FMR volume) were assessed with echocardiography before and 6 months after CRT. The study end points included all-cause death or hospitalization assessed in 12 ± 3 months (range 1 to 18). A total of 71 patients (65%) responded to CRT at 6 months. FMR response was observed in 49 (69%) of the CRT responders and 8 (20%) of the CRT nonresponders (p <0.001). Although the baseline QRS durations were similar, the paced QRS durations were shorter (p = 0.012) and the ?QRS values were greater (p = 0.003) in FMR responders compared with FMR nonresponders. There was a linear correlation between ?QRS and change in regurgitant volume (r = 0.49, p <0.001). At multivariate analysis, baseline tenting area (p = 0.012) and ?QRS (p = 0.028) independently predicted FMR response. A ?QRS ? 20 ms was related to CRT response, FMR improvement, and lower rates of death or hospitalization during follow-up (p values <0.05). In conclusion, QRS narrowing after CRT independently predicts FMR response. A ?QRS ?20 ms after CRT is associated with a favorable outcome in all clinical end points.eninfo:eu-repo/semantics/embargoedAccessMitral Valve InsufficiencyMitral ValveIschemic MitralArticle117341241910.1016/j.amjcard.2015.11.010Q3Q1