Background: Electromechanical coupling may play a significant role in the association between abnormal myocardial mechanics and heterogeneity of repolarization. This study sought to assess the potential relationship between the left atrial volume index (LAVI), which is an important marker of cardiac diastolic function, and ventricular repolarization variables, such as the QT interval, Tpeak-to-Tend (Tpe) interval and Tpe/QT ratio, in an apparently healthy Chinese population.
Methods: This was a community-based cross-sectional study conducted in Shenyang, China. A total of 414 healthy subjects aged 35– 91 years, including 186 men (44.9%), were enrolled. In addition to performing clinical and laboratory measurements, all subjects underwent comprehensive echocardiography and standard 12-lead electrocardiography. Echocardiographic and electrocardiographic results were analysed separately and in a blinded fashion. Correlation and regression analyses were applied to determine associations.
Results: Subjects were divided into four groups according to quartile of LAVI levels (< 16.0, 16.0– 18.9, 19.0– 22.5 and > 22.5 mL/m²). Ventricular repolarization variables, such as QT interval and QTc interval, gradually increased with the progression from low to high LAVI levels (P< 0.05). LAVI was positively and significantly correlated with the QT interval, the QTc interval, and the Tpe interval (P< 0.01). After adjusting for age and other possible confounders, LAVI showed significant and independent associations with the QT interval and the QTc interval (P< 0.001; P=0.003).
Conclusion: Echocardiographic LAVI is linearly associated with ventricular repolarization variables even in healthy people.
Keywords: left atrial volume index, QT interval, Tpe interval, diastolic dysfunction, ventricular repolarization