Discordant atrial and ventricular remodeling in mitral valve prolapse : a multicenter cohort study

Background Mitral valve prolapse (MVP) is associated with heterogeneous cardiac remodeling that may extend beyond mitral regurgitation (MR) severity. The prognostic significance of discordant atrial and ventricular remodeling phenotypes remains incompletely defined. Purpose To characterize left atrial (LA) and left ventricular (LV) remodeling phenotypes and to evaluate their prognostic value beyond MR severity. Methods We retrospectively analyzed 639 patients with MVP from multicenter cohorts (2010–2024). Remodeling phenotypes were defined using indexed LA volume ≥40 mL/m² and indexed LV end-diastolic diameter ≥31 mm/m²: no remodeling, isolated LA remodeling, isolated LV remodeling, and combined LA+LV remodeling. The primary endpoint was a composite of mitral valve surgery, new-onset atrial fibrillation, ventricular arrhythmias, heart failure hospitalization, or cardiovascular death. Multivariate Cox models were adjusted for MR severity to evaluate the independent prognostic value of remodeling phenotypes. Results Four remodeling phenotypes were identified: no remodeling (25%), isolated LA remodeling (30%), isolated LV remodeling (7%), and combined LA+LV remodeling (38%). LA remodeling was associated with older age, higher MR grades, and increased atrial fibrillation prevalence, whereas LV remodeling occurred predominantly in younger women with frequent premature ventricular contractions and late gadolinium enhancement in 28% of patients. Over a median follow-up of 6.2 years, MR severity was the strongest predictor of events (HR 5.17, 95% CI 2.91–9.84; p<0.001), consistent with prior literature. Isolated LA remodeling (HR 2.65; p = 0.021) and combined LA+LV remodeling (HR 3.57; p = 0.001) remained independently associated with adverse outcomes, while isolated LV remodeling was not (HR 2.67; p = 0.141). Differences between phenotypes were attenuated in patients with non-severe MR. Conclusions LA remodeling identifies a dominant high-risk phenotype in MVP beyond MR severity, while isolated LV dilation defines a distinct arrhythmogenic but comparatively lower-risk profile. Integrating remodeling phenotypes may refine risk stratification, although MR severity remains the central prognostic driver.