Prevalence of Mitral Annulus Disjunction and Mitral Valve Prolapse in Patients With Idiopathic Ventricular Fibrillation

Abstract

Background Idiopathic ventricular fibrillation (IVF) is diagnosed in patients with ventricular fibrillation of which the origin is not identified after extensive evaluations. Recent studies suggest an association between mitral annulus disjunction (MAD), mitral valve prolapse (MVP), and ventricular arrhythmias. The prevalence of MAD and MVP in patients with IVF in this regard is not well established. We aimed to explore the prevalence of MAD and MVP in a consecutive cohort of patients with IVF compared with matched controls. Methods and Results In this retrospective, multicenter cohort study, cardiac magnetic resonance images from patients with IVF (ie, negative for ischemia, cardiomyopathy, and channelopathies) and age- and sex-matched control subjects were analyzed for the presence of MAD (≥2 mm) and MVP (>2 mm). In total, 72 patients (mean age 39±14 years, 42% women) and 72 control subjects (mean age 41±11 years, 42% women) were included. MAD in the inferolateral wall was more prevalent in patients with IVF versus healthy controls (7 [11%] versus 1 [1%], P=0.024). MVP was only seen in patients with IVF and not in controls (5 [7%] versus 0 [0%], P=0.016). MAD was observed in both patients with (n=4) and without (n=3) MVP. Conclusions Inferolateral MAD and MVP were significantly more prevalent in patients with IVF compared with healthy controls. The authors advocate that evaluation of the mitral valve region deserves extra attention in the extensive screening of patients with unexplained cardiac arrest. These findings support further exploration of the pathophysiological mechanisms underlying a subset of IVF that associates with MAD and MVP.

Keywords: cardiac magnetic resonance imaging; idiopathic ventricular fibrillation; mitral annulus disjunction; mitral valve prolapse; ventricular arrhythmias.

Figure 1. Inclusion flowchart.

Patients with IVF included in a large national registry from 3 tertiary centers were included. CMR indicates cardiac magnetic resonance; and IVF, idiopathic ventricular fibrillation.

Figure 2. Measurements of longitudinal MAD and MVP distance on CMR imaging.

All images are obtained at end‐systole. The blue line connects the annular hinge points of the mitral valve, the white arrows are longitudinal MAD measurements, and the orange arrow is the MVP measurement. CMR indicates cardiac magnetic resonance; LA, left atrium; LV, left ventricle; MAD, mitral annulus disjunction; and MVP, mitral valve prolapse.

Figure 3. Prevalence of mitral annulus disjunction (MAD) and mitral valve prolapse (MVP) in patients with idiopathic ventricular fibrillation (VF) compared with healthy controls.

In total, 144 patients were enrolled in the study, 72 patients with idiopathic VF and 72 healthy controls. All patients were screened for presence of MAD and MVP on cardiac magnetic resonance (CMR) imaging by 2 blinded observers. MAD in the inferolateral wall was more prevalent in patients with idiopathic VF compared with controls (P=0.024). MVP was also more prevalent in patients with idiopathic VF compared with controls (P=0.016). LA indicates left atrium; and LV, left ventricle.