Bileaflet mitral valve prolapse (biMVP) is associated with frequent ventricular ectopy (VE) and malignant ventricular arrhythmia. We examined the effect of mitral valve (MV) surgery on VE burden in biMVP patients. We included 32 consecutive patients undergoing MV surgery for mitral regurgitation secondary to biMVP between 1993 and 2012 at Mayo Clinic who had available pre- and post-operative Holter monitoring data. Characteristics of patients with a significant reduction in postoperative VE (group A, defined as >10% reduction in VE burden compared to baseline) were compared with the rest of study patients (group B). In the overall cohort, VE burden was unchanged after the surgery (41 interquartile range [16, 196] pre-surgery vs. 40 interquartile range [5186] beats/hour [bph] post-surgery; P = 0.34). However, in 17 patients (53.1%), VE burden decreased by at least 10% after the surgery. These patients (group A) were younger than the group B (59 ± 15 vs. 68 ± 7 years; P = 0.04). Other characteristics including pre- and postoperative left ventricular function and size were similar in both groups. Age <60 years was associated with a reduction in postoperative VE (odds ratio 5.8; 95% confidence interval, 1.1-44.7; P = 0.03). Furthermore, there was a graded relationship between age and odds of VE reduction with surgery (odds ratio 1.9; 95% confidence interval 1.04-4.3 per 10-year; P = 0.04). MV surgery does not uniformly reduce VE burden in patients with biMVP. However, those patients who do have a reduction in VE burden are younger, perhaps suggesting that early surgical intervention could modify the underlying electrophysiologic substrate.

Sudden cardiac death (SCD) from ventricular fibrillation (VF) can occur in mitral valve prolapse (MVP) in the absence of other comorbidities including mitral regurgitation, heart failure or coronary disease. Although only a small proportion with MVP are at risk, it can affect young, otherwise healthy adults, most commonly premenopausal women, often as the first presentation of MVP. In this review, we discuss arrhythmic mechanisms in MVP and mechanistic approaches for sudden death risk assessment and prevention. We define arrhythmogenic or arrhythmic MVP (AMVP) as MVP associated with complex and frequent ventricular ectopy, and malignant MVP (MMVP) as MVP with high risk of SCD. Factors predisposing to AMVP are myxomatous, bileaflet MVP and mitral annular disjunction (MAD). Data from autopsy, cardiac imaging and electrophysiological studies suggest that ectopy in AMVP is due to inflammation, fibrosis and scarring within the left ventricular (LV) base, LV papillary muscles and Purkinje tissue. Postulated mechanisms include repetitive injury to these regions from systolic papillary muscle stretch and abrupt mitral annular dysmotility (excursion and curling) and diastolic endocardial interaction of redundant mitral leaflets and chordae. Whereas AMVP is seen relatively commonly (up to 30%) in those with MVP, MVP-related SCD is rare (2–4%). However, the proportion at risk (i.e., with MMVP) is unknown. The clustering of cardiac morphological and electrophysiological characteristics similar to AMVP in otherwise idiopathic SCD suggests that MMVP arises when specific arrhythmia modulators allow for VF initiation and perpetuation through action potential prolongation, repolarization heterogeneity and Purkinje triggering. Adequately powered prospective studies are needed to assess strategies for identifying MMVP and the primary prevention of SCD, including ICD implantation, sympathetic modulation and early surgical mitral valve repair. Given the low event rate, a collaborative multicenter approach is essential.

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.