Arrhythmic Mitral Valve Prolapse
- Miller MA, Dukkipati SR, Turagam M, Liao SL, Adams DH, Reddy VK.
- Arrhythmic Mitral Valve Prolapse: JACC Review Topic of the Week. J Am Coll Cardiol 2018;72:2904-2914.
The following are 10 points to remember from this review on arrhythmic mitral valve prolapse (MVP):
- MVP is a relatively common cardiac valvular disorder, affecting about 1-3% of the population. Characteristics include superior displacement of mitral valve leaflet(s) during systole by at least 2 mm, myxomatous degeneration, and thickening of the leaflets.
- Clinical consequences of MVP include mitral regurgitation (MR), left ventricular (LV) dysfunction/congestive heart failure, infective endocarditis, atrial fibrillation, thromboembolism, and ventricular arrhythmias/sudden cardiac death (SCD).
- More contemporary studies indicate that the risk of SCD in patients with MVP may not be as low as that reported in the older literature. However, the true incidence is unknown since, among other reasons, it may be difficult to ascribe sudden death to the finding of MVP at autopsy.
- The risk of SCD attributable to MVP is likely underestimated. For example, in a long-term European study involving young people (ages <35 years), MVP was found to be the third most common cause of sudden death (incidence, 12%), behind arrhythmogenic right ventricular cardiomyopathy (24%), and coronary artery disease (20%).
- Prospective identification of patients with MVP who may be at risk of SCD is challenging. Some risk factors include female gender, bileaflet prolapse, frequent or complex premature ventricular complexes (PVCs), and biphasic or inverted T waves in the inferior leads on the electrocardiogram (ECG), and myocardial scar. However, some of these characteristics may not be sufficiently specific. For example, these T-wave changes may be seen in about 40% of patients with MVP in the absence of sustained ventricular arrhythmias.
- PVCs originating from the papillary muscles and the fascicular system may be especially arrhythmogenic, and may herald episodes of ventricular fibrillation.
- Cardiac imaging not only helps establish the diagnosis of MVP, but it may also aid in risk stratification. A spiked high velocity signal across the lateral mitral annulus on echocardiography (“Pickelhaube sign”) is more likely to be present in patients with (67%) than without (22%) ventricular arrhythmias. Further, evidence of myocardial scar (late gadolinium enhancement) on magnetic resonance imaging (MRI) was more likely to be present in patients with this echocardiographic finding.
- Focal LV papillary muscle fibrosis or inferobasal scar was identified in about 90% of patients with MVP and SCD/complex ventricular arrhythmias. These findings have been corroborated in post-mortem studies.
- It is reasonable to obtain a cardiac MRI to evaluate for the possibility of myocardial scar in patients with MVP and complex ventricular ectopy. In patients with multiple risk factors, some clinicians may recommend an electrophysiology study to evaluate for inducible sustained ventricular arrhythmias. However, the role of invasive risk stratification is not well established.
- It is reasonable to prescribe beta-blocker medications in patients with frequent or complex ventricular ectopy. An implantable cardioverter-defibrillator should be implanted in patients with MVP and sustained ventricular arrhythmias or aborted SCD. Catheter ablation of ventricular arrhythmias is reasonable for patients with frequent ventricular ectopy associated with symptoms or LV dysfunction, and ventricular tachycardia, or even ventricular fibrillation (which may be triggered by PVCs originating from the papillary muscle or the Purkinje system.
Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Valvular Heart Disease, Atherosclerotic Disease (CAD/PAD), Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Magnetic Resonance Imaging, Mitral Regurgitation
Keywords: Arrhythmias, Cardiac, Atrial Fibrillation, Cardiomyopathies, Catheter Ablation, Coronary Artery Disease, Death, Sudden, Cardiac, Electrocardiography, Heart Failure, Heart Valve Diseases, Defibrillators, Implantable, Endocarditis, Mitral Valve Insufficiency, Mitral Valve Prolapse, Magnetic Resonance Imaging, Tachycardia, Ventricular, Thromboembolism, Ventricular Fibrillation
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