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Arrhythmic Mitral Valve Prolapse in Unexplained Cardiac Arrest
Quick Takes
- In a large multicenter cohort of unexplained sudden cardiac death, about 6% of subjects had mitral valve prolapse (MVP).
- Bileaflet MVP was significantly associated with arrhythmogenic MVP (78% vs. 12.5%; odds ratio, 25.2).
Study Questions:
What is the prevalence and what are the characteristics of mitral valve prolapse (MVP) in a large cohort of patients with unexplained cardiac arrest (UCA)?
Methods:
Patients were enrolled in CASPER, a multicenter registry of initially UCA. Echocardiograms were reviewed for MVP. Patients with MVP were divided into two groups: 1) those with idiopathic ventricular fibrillation (VF) who had arrhythmic MVP, and 2) those with an alternative diagnosis (thought to have nonarrhythmic MVP).
Results:
Among 571 patients with initially UCA, 34 patients (6%) had MVP. The prevalence of definite MVP was significantly higher in patients with idiopathic VF than those with an alternative diagnosis (6.6% vs. 2.4%). Bileaflet prolapse was significantly associated with arrhythmogenic MVP (78% vs. 12.5%; odds ratio, 25.2). The proportion of patients with arrhythmogenic MVP who received appropriate implantable cardioverter-defibrillator (ICD) therapies over a median follow-up of 42 months was 21%.
Conclusions:
The authors conclude that MVP is associated with otherwise UCA, with a prevalence of 6.6%. Bileaflet prolapse appears to be a feature of arrhythmogenic MVP.
Perspective:
The study of the role that MVP may play in UCA has been hampered by the relatively high prevalence of MVP and a relatively small incidence of unexplained sudden cardiac death. Additionally, there have been varying definitions of MVP and much research came from single-center observational studies likely influenced by selection bias. Features that distinguish arrhythmogenic MVP from bystander MVP have not been well established. The current study’s strength lies in the fact that the data come from a large multicenter registry and the causes of UCA were rigorously adjudicated. In this study, only bileaflet prolapse was statistically significantly associated with arrhythmogenic MVP. Patients with arrhythmogenic MVP also had a non–statistically significant tendency to more frequent mitral annular disjunction, premature ventricular contractions, and family history of sudden cardiac death. A great deal of work remains before we can begin to risk stratify patients with MVP who should be protected with an ICD.
Clinical Topics: Arrhythmias and Clinical EP, Implantable Devices, SCD/Ventricular Arrhythmias
Keywords: Heart Arrest, Mitral Valve Prolapse
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