Relation of Mitral Leaflet Elongation to Nonsustained Ventricular Tachycardia in Patients with Obstructive Hypertrophic Cardiomyopathy

The impact of mitral valve abnormality on the occurrence of non-sustained ventricular tachycardia (NSVT) in patients with hypertrophic cardiomyopathy (HC) has not been well determined. We sought to demonstrate the relation of mitral valve abnormalities with NSVT in patients with obstructive HC. Three hundred and sixteen adult patients with obstructive HC with at least 1 Holter electrocardiographic monitoring and cardiac magnetic resonance (CMR) from 2014 to 2018 were enrolled. CMR images and Holter electrocardiography were analyzed in all patients. NSVT occurred in 50 patients (16%). Compared with those without NSVT, anterior mitral leaflet and posterior mitral leaflet lengths was significantly increased in patients with NSVT (AML 32.0 ± 5.0mm vs. 26.1±4.8mm, p<0.001; PML 17.7±3.7mm vs. 15.2±2.7mm, p<0.001, respectively). Multivariate logistic regression analysis indicated that elongated AML and PML were significantly independent predictors of NSVT (AML: OR 1.261, 95%CI 1.156-1.375, p<0.001; PML: OR 1.126, 95%CI 1.001-1.265, p=0.047). Furthermore, the area under the receiver operating characteristic curve for AML was 0.812. At a cutoff valve of 27.5mm, AML length had a sensitivity of 86% and specificity of 65%. Elongated mitral leaflets independently correlated with NSVT in patients with obstructive HC. Furthermore, the morphological abnormalities of mitral valve could serve as a useful marker for improving risk stratification of SCD and may play a role in optimizing surgical strategy for patients with obstructive HC.