QT dispersion is reduced after valve replacement in patients with aortic stenosis

Abstract

Objective: To investigate whether QT dispersion is a reliable index of the severity of aortic stenosis and left ventricular hypertrophy in the setting of aortic stenosis.

Design: A retrospective analysis of the results of echocardiography and electrocardiography before and after aortic valve replacement.

Setting: Tertiary centre.

Patients: 36 men (30 white and six black) with symptomatic aortic stenosis requiring valve replacement.

Results: All patients had significant aortic stenosis (mean (SD) aortic valve area 0.68 (0.18) cm2) and evidence of left ventricular hypertrophy (left ventricular mass index (LVMI): 267 (90) g/m2). Before aortic valve replacement, QT dispersion was correlated with mean aortic valve area and LVMI (r = 0.697, p < 0.001, and r = 0.59, p < 2.4 x 10(-6), respectively). QT dispersion and QT corrected for heart rate dispersion decreased from 133 (54) to 71 (33) ms and from 151 (64) to 94 (76) ms, respectively (p < 0.001 for both). LVMI regressed after aortic valve replacement to 190 (79) g/m2, p < 0.01.

Conclusions: QT dispersion is increased in association with LVMI in patients with significant symptomatic aortic stenosis. Aortic valve replacement reduces QT dispersion and LVMI. QT dispersion could be a useful indicator of risk and risk reduction in patients with significant symptomatic aortic stenosis.

Figure 1

Individual QT dispersion values before and after aortic valve replacement

Figure 2

Relation between QT and mean aortic valve area before aortic valve replacement.

Figure 3

Relation between QT and left ventricular (LV) mass index before aortic valve replacement.