Elsevier

Heart Rhythm

Volume 13, Issue 2, February 2016, Pages 498-503
Heart Rhythm

Mitral valve prolapse and sudden cardiac arrest in the community

https://doi.org/10.1016/j.hrthm.2015.09.026Get rights and content

Background

Mitral valve prolapse (MVP) is relatively common in the general population with recently reported prevalence of 1% and familial clustering (Framingham Heart Study). However, its association with ventricular arrhythmias and sudden cardiac arrest (SCA) remains controversial.

Objectives

The purpose of this study was to characterize the frequency and clinical profile of patients with MVP who suffer SCA in the community.

Methods

Patients with SCA cases were prospectively identified in the population-based Oregon Sudden Unexpected Death Study (population ~1 million). The presence of MVP was identified from echocardiograms recorded prior but unrelated to the SCA event. The detailed clinical profile of patients with SCA and MVP was compared with that of SCA patients without MVP to identify potential differences.

Results

A total of 729 SCA patients were evaluated over a 12-year period (mean age 69.5 ± 14.8 years; 64.6% men). MVP was observed in 17 (2.3%) prior to the SCA event (95% confidence interval 1.2%–3.4%). Mitral regurgitation was present in 14 SCA patients with MVP (82.3%) and was moderate or severe in 10 (58.8%). Compared with SCA patients without MVP, SCA patients with MVP were younger (mean age 60.9 ± 16.4 years vs 69.7 ± 14.7 years; P = .02), with fewer risk factors (diabetes 5.9% vs 46.4%; P = .001; hypertension 41.2% vs 78.9%; P = .001) or known coronary disease (29.4% vs 65.6%; P < .001).

Conclusion

MVP was observed in a small proportion (2.3%) of SCA patients in the general population, suggesting a low risk overall. Since SCA patients with MVP were characterized by younger age and relatively low cardiovascular comorbidity, a focus on imaging for valve structure/insufficiency as well as genetics could aid future risk stratification approaches.

Introduction

Mitral valve prolapse (MVP) has been reported as a relatively common finding in the general population.1, 2 A recent analysis from the Framingham cohort showed a prevalence of 1% with almost equal sex distribution and familial clustering.1 Patients with relatively nonspecific symptoms such as palpitations and atypical chest pain who are found to have MVP continue to represent a major clinical conundrum for the practicing cardiologist.3

The existing literature continues to generate significant controversy about this condition. Several studies indicate that a subset of patients may suffer adverse outcomes, with sudden cardiac arrest (SCA) potentially the most devastating of these. SCA has been described as one of the possible outcomes on follow-up in MVP,4, 5 and several instances of SCA in young patients with MVP have been reported.6, 7 In addition, the occurrence of ventricular arrhythmias on resting or ambulatory electrocardiograms is reported to be higher in patients with MVP,8, 9 though some studies have challenged this finding.10 Conversely, other natural history studies2, 4 indicate that MVP may have a benign prognosis. Considering the fact that MVP is a common, often incidental diagnosis in the community, the extent to which MVP contributes to excess SCA risk therefore continues to remain unclear. It is conceivable that a rare complication of a relatively common condition may account for a sizable number of events. Thus, it is worthwhile to examine the relevance of MVP vis-à-vis SCA in the general population. Population-based studies looking at the prevalence of MVP among SCA patients are scarce. In the ongoing Oregon Sudden Unexpected Death Study (Oregon-SUDS), we have systematically collected data on SCA in the community over a period of 13 years. We sought to ascertain the frequency of MVP in SCA patients in the general population and characterize the clinical profile of SCA cases with MVP.

Section snippets

Study population

Details of case and control ascertainment in the Oregon-SUDS have been published earlier.11, 12 The Oregon-SUDS is an ongoing prospective study of SCA in the Portland, Oregon metropolitan area (population ~1 million) presently in its 14th year. Briefly, multiple source surveillance, which includes first responders (Portland fire department and ambulance service), local hospital emergency departments, and the county medical examiner’s office, is used to track cases of out-of-hospital cardiac

Prevalence of MVP in the SCA population

Of 3040 SCA subjects, 729 patients with relevant echocardiograms were analyzed over a 12-year period. The differences between patients with and without echocardiograms are listed in Online Supplemental Table 1. Patients with echocardiograms were more likely to be older and have known cardiovascular risk factors. The mean time between the performance of echocardiography and the SCA event was 654 ± 788 days; 80% of echocardiograms were performed within 3 years before the event. The clinical,

Discussion

In this community-based study, MVP was observed in 2.3% of SCA patients. SCA patients with MVP were distinguished by younger age and lesser prevalence of cardiovascular risk factors as well as known coronary artery disease. Most MVP patients had associated MR, and the presence of moderate or severe MR was much more likely in patients with MVP.

The prevalence of MVP in our SCA population is similar to the prevalence of 2.4% reported by Freed et al2 in the general population in the Framingham

Conclusion

MVP was present in 2.3% of SCA patients in this population-based study. SCA patients with MVP were younger and less likely to have cardiac or noncardiac disease conditions. Future prospective studies that focus on imaging for valve structure/insufficiency as well as genetic propensity are likely to have the most yield for SCA risk stratification in the MVP patient.

Clinical Perspectives

Mitral valve prolapse (MVP) is a common condition in the community and is often encountered by clinicians in

Acknowledgments

We acknowledge the significant contribution of American Medical Response, Portland/Gresham fire departments, and the Oregon State Medical Examiner’s office.

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    This work was supported in part by the National Heart, Lung, and Blood Institute (grant nos. R01HL105170 and R01HL122492, to Dr Chugh). Dr Chugh holds the Pauline and Harold Price Chair in Cardiac Electrophysiology at the Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA.

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