Functional mitral regurgitation and ventricular arrhythmias in patients with cardiac resynchronization therapy

Abstract

Abstract Introduction In patients with heart failure (HF), the occurrence of ventricular arrhythmias (VAs) is associated with prognosis, and advanced HF can cause VAs. In HF patients developed moderate to severe functional mitral regurgitation (FMR), a transcatheter mitral valve repair therapy has significantly reduced the hospitalization and mortality rates compared to guideline-directed medical therapy. Although the mechanisms of arrhythmias are multiple, it is unclear whether FMR is involved in the development of VAs advanced HF patients. Methods and results We retrospectively examined 176 cardiac resynchronization therapy (CRT) patients (78% men, median age 67 years) without FMR before CRT implanted between 2010 and 2018. Worsening FMR was defined as developing moderate to severe FMR after CRT. During median follow-up of 40 (quartile range, 23-60) months, worsening FMR was detected in 26 (15%) patients at a median of 30 (quartile range, 12–75) months after CRT implantation. There was no difference in age, New York Heart Association functional class, QRS width before CRT and the rate of responders between patients with and without worsening FMR. Patients with worsening FMR had a tendency of larger left ventricular end-systolic dimension (58 [53-68] vs. 53 [47-60] mm, p<0.10), a significantly higher rate of female (38% vs. 19%, p<0.05) and a significantly larger left atrial volume index (LAVI) (63 [43-81] vs. 48 [35-62] ml/m2, p<0.05). By multivariate logistic regression analysis, female gender (odds ratio 4.3) and baseline LAVI (odds ratio 1.04 per a ml/m2 increase) were independent factors associated with worsening FMR. There was a significantly higher incidence of HF hospitalization (50% vs 15%, log-rank P<0.05) (Figure 1) and a higher incidence of VAs, defined as sustained ventricular tachyarrhythmias requiring implantable-cardioverter defibrillator therapy or external defibrillation, in patients with worsening FMR than patients without worsening FMR (65% vs 38%, log-rank P<0.05) (Figure 2). Multivariate analysis showed that worsening FMR was independently associated with the development of VAs (hazard ratio 2.77, 95% confidence interval 1.13-6.83). Conclusions In patients with HF and CRT, female gender and baseline LAVI were associated with worsening FMR after CRT. We need to pay attention to changes in the FMR that can be associated with developing VAs after CRT implantation.