Delling, Francesca N.

Abstract Background Arrhythmogenic mitral valve prolapse (AMVP) is increasingly recognized as a cause of sustained ventricular arrhythmias (VA) and sudden cardiac death. Although prior studies have identified clinical and imaging risk markers in AMVP, it remains unclear whether the arrhythmogenic phenotype differs between women and men. Purpose To investigate sex-specific differences in clinical profiles, structural substrates, and arrhythmia presentations in patients with AMVP who experienced sustained VA. Methods We conducted a sex-based sub-analysis of a multicenter cohort (35 centers from 15 countries) of patients with AMVP and sustained VA. Participants were grouped by sex and by initial arrhythmia type (sustained monomorphic ventricular tachycardia [SMVT] vs ventricular fibrillation [VF]). Data collected included clinical history, ECG findings, echocardiographic measurements, and cardiac MRI (CMR) markers, such as late gadolinium enhancement (LGE) patterns and mitral annular disjunction (MAD). These factors were compared across groups. Results The study comprised 129 women (57%) and 96 men (43%). Women were diagnosed at younger ages (39±16 years vs. 49±16 years, p<0.03) and had more frequently a family history of MVP (22% vs 10%, p=0.027). MAD was significantly more common in women (66% vs 48%, p=0.015) while LGE was more frequently observed in men than women (N=39 (72%) vs N=41 (53%), p=0.028), with no significant regional patterns (myocardial and/or papillary muscle). ECG T-wave inversion (p=0.627), PVC burden (p>0.03) and arrhythmia types were similar in men and women. However, stress was a more often commonly recognized as the initiating trigger for VA in men than in women (38% [N=24] vs. 18% [N=18], p<0.05). The overwhelming majority of VA were initiated by PVCs in both sexes with no differences in the initiating mechanisms. Conclusion In patients with AMVP presenting with sustained VA, the arrhythmic phenotype and initiating mechanisms are similar between sexes, although stress was a significantly stronger trigger for VA in men. Women more often exhibited MAD, whereas LGE was more frequent in men. These findings suggest that structural and tissue-based markers, rather than sex alone, contribute to the development of malignant arrhythmias in AMVP.

BACKGROUND: Patients with arrhythmogenic mitral valve prolapse syndrome are at increased risk for life-threatening ventricular arrhythmias, but studies have been limited by small sample sizes. We sought to assemble an international arrhythmogenic mitral valve prolapse syndrome registry to delineate the clinical, imaging, and treatment characteristics of patients with arrhythmogenic mitral valve prolapse syndrome who survived sudden cardiac arrest (SCA) or had sustained ventricular tachycardia (VT) or ventricular fibrillation. METHODS: In this descriptive registry, we characterized patients with arrhythmogenic mitral valve prolapse syndrome who survived SCA, sustained VT, or ventricular fibrillation. Deidentified data were abstracted locally and combined centrally. RESULTS: We included 148 patients who had SCA or VT/ventricular fibrillation. Patients had a mean age of 43.7±15.4 years; 68% were women, 73% had bileaflet prolapse, 65% had mitral annular disjunction, 67% had nonsustained VT, and 59% had inferolateral T-wave inversions. Syncope (n=54, 48%) and anterolateral T-wave inversion (n=26, 22%) were relatively common. Catheter ablation was performed in 50 (35%) patients for premature ventricular complexes and in 18 (17.7%) patients for VT. Sites of origin for arrhythmias were commonly in the papillary muscles, fascicles, mitral annulus, and inferior/inferolateral left ventricle. CONCLUSIONS: In this international descriptive registry of patients with arrhythmogenic mitral valve prolapse syndrome and SCA, patients were young, women, and had bileaflet mitral valve prolapse, mitral annular disjunction, inferolateral T-wave inversions, and nonsustained VT. A history of syncope and anterolateral T-wave inversions was relatively common in patients who survived SCA or sustained VT/ventricular fibrillation.

Abstract Aims Mitral valve prolapse (MVP) is a common valvular heart disease with a prevalence of >2% in the general adult population. Despite this high incidence, there is a limited understanding of the molecular mechanism of this disease, and no medical therapy is available for this disease. We aimed to elucidate the genetic basis of MVP in order to better understand this complex disorder. Methods and results We performed a meta-analysis of six genome-wide association studies that included 4884 cases and 434 649 controls. We identified 14 loci associated with MVP in our primary analysis and 2 additional loci associated with a subset of the samples that additionally underwent mitral valve surgery. Integration of epigenetic, transcriptional, and proteomic data identified candidate MVP genes including LMCD1, SPTBN1, LTBP2, TGFB2, NMB, and ALPK3. We created a polygenic risk score (PRS) for MVP and showed an improved MVP risk prediction beyond age, sex, and clinical risk factors. Conclusion We identified 14 genetic loci that are associated with MVP. Multiple analyses identified candidate genes including two transforming growth factor-β signalling molecules and spectrin β. We present the first PRS for MVP that could eventually aid risk stratification of patients for MVP screening in a clinical setting. These findings advance our understanding of this common valvular heart disease and may reveal novel therapeutic targets for intervention.