Regression of left ventricular hypertrophy results in improvement of QT dispersion in patients with hypertension

Abstract

Objectives Increased QT dispersion has been considered as predisposing to ventricular arrhythmias in hypertrophic cardiomyopathy, congestive heart failure, and coronary artery disease. An increased QT dispersion has also been found in hypertensive patients with left ventricular hypertrophy (LVH). The data on the effect of LVH regression on QT dispersion are limited. Methods and Results To assess the relation of LVH regression and QT dispersion decrease, 68 patients (42 men and 26 women, mean age 56.3 ± 9.5 years) with uncomplicated essential hypertension were studied. All underwent full electrocardiographic and echocardiographic studies at baseline and after 6 months of monotherapy, 29 with angiotensin-converting enzyme inhibitors and 39 with calcium antagonists. QT dispersion was calculated by subtracting the shortest QT from the longest QT, in absolute value (QTmax – QTmin). It was also corrected with Bazett’s formula (QTc dispersion). Left ventricular mass index was assessed according to the Devereux formula. After treatment, LVH decreased with both angiotensin-converting enzyme inhibitors (from 155 to 130 g/m 2 , P < .001) and calcium antagonists (156 to 133/92/m 2 , P < .001). QT dispersion decreased both after angiotensin-converting enzyme inhibitor treatment (from 82 to 63 ms) and calcium antagonist treatment (from 77 to 63 ms, both P < .001). There was a significant correlation of QT dispersion and left ventricular mass after therapy ( r = 0.36, P < .005). There was a correlation of the degree of LVH and QT dispersion decrease ( r = 0.27, P < .05). Conclusions It is concluded that LVH regression influences ΔQT favorably. Its prognostic value has yet to be determined. (Am Heart J 1998;136:765-8.)