Prolonged Tp-e interval and Tp-e/QT ratio in patients with mitral annulus disjunction

Abstract

Abstract Background Mitral annulus disjunction (MAD) is an abnormal atrial displacement of the mitral valve leaflet hinge point. MAD has been associated with mitral valve prolapse (MVP) and arrhythmic events. T-wave peak to T-wave end interval (Tp-e) and Tp-e/QTc are electrocardiographic (ECG) indices to predict ventricular tachyarrhythmia and cardiovascular mortality. Purpose We aimed to evaluate ventricular repolarization dispersion by using the Tp-e interval and Tp-e/QT ratio in patients with MAD and healthy controls. Methods A total of 35 patients with MAD (age 40.4±8.2 years; 66% female) and 37 healthy controls (age 37.6±9.5 years; 68% female) were enrolled. All subjects were evaluated by 12 lead standard ECG, 24-hour ambulatory ECG, and transthoracic echocardiography. The MAD distance was measured from the left atrial wall-mitral valve leaflet junction to the top of the left ventricular wall during end-systole in the parasternal long-axis view. The standard 12-lead electrocardiograms were analyzed; QTc, Tp-e and Tp-e/QTc were calculated. The Tp-e interval was defined as the interval from the peak of the T wave to the end of the T wave from precordial leads. Finally, the Tp-e/QT ratio was calculated from these measurements. The normality assumption was checked with the Shapiro-Wilk test and the Mann–Whitney U test was used for inter-group comparisons. Results Tp-e interval (61.9±6.0 ms vs. 77.1±5.9 ms, p<0.001) and Tp-e/QT ratio (0.14±0.01 vs. 0.17±0.02, p<0.001) were significantly prolonged in patients with MAD than in the control group. MVP was present in 24 (69%) patients with MAD. The prevalence of 30 premature ventricular contractions / hour were higher in MAD subgroup without MVP than those MAD with MVP (54.5% vs 16.7%, p=0.041). Mean MAD distance measured by echocardiography was 5.7±1.5 mm. The Spearman's rank-order correlation analyses revealed positive correlations of MAD distance with Tp-e interval (r=0.620, p=0.001) and Tp-e/QT ratio (r=0.372, p=0.028). Conclusions The patients with MAD had a prolonged Tp-e interval and Tp-e/QT ratio compared with normal subjects. Furthermore, this prolongation was well correlated with MAD distance. Patients with MAD, particularly with higher MAD distance, should be followed closely for arrhythmic outcomes. MAD distance and Tp-e interval Funding Acknowledgement Type of funding source: None