Title : Associations of 24-hour ambulatory blood pressure profiles and echocardiographic findings with prolonged QTc interval in hypertensive patients
Abstract:
Background: Prolonged corrected QT (QTc) interval is associated with an increased risk of cardiovascular mortality and sudden cardiac death. We sought to investigate whether 24-hour (h) ambulatory blood pressure (ABP) profiles and echocardiographic findings with QTc prolongation in hypertensive patients.
Methods: We studies 141 hypertensive patients (66 men and 75 women; mean age, 52.3±15.4 years) who underwent 24-h ABP monitoring and transthoracic Doppler echocardiography. The QTc interval was measured at standard 12-lead electrocardiograms using Bazett’s formula and QTc prolongation was defined as over 450msec in men and over 460msec in women.
Results: Although the QTc interval was more prolonged in women than in men, the prevalence of QTc prolongation was similar between them (30.3% for men vs. 30.7% for women, p=0.963). The systolic BP (SBP) of 24-h, daytime and night-time, night-time diastolic BP (DBP), left ventricular mass index (LVMI), and left atrial volume index were associated with QTc prolongation. However, multivariate analysis showed that LVMI was independently associated with QTc prolongation. After adjusting covariates, night-time SBP was found to be an independent determinant of QTc prolongation.
Conclusions: Our study suggests that the mechanism of ventricular repolarization differs between men and women. It could partially explain for the susceptibility of women to arrythmogenesis among hypertensive patients.
