QT dispersion in hypertensive Nigerians with and without left ventricular hypertrophy

Increased QT dispersion (QTd) has been implicated as a marker of arrhythmogenesis and cardiac death. Paucity of literature on QTd in Nigeria necessitated an inquiry into QTd in adult hypertensive population. This study sought to: (i) compare the QTd values of adult hypertensive subjects with age and sex matched normotensive subjects and (ii)examine the relationship between QTd and left ventricular hypertrophy (LVH).

One hundred and fifty-one hypertensive patients and 101 age and sex-matched controls were recruited into this study. A resting 12- lead ECG was obtained from all subjects for determination of QTd and ECG LVH using Sokolow Lyon (SL) and Araoye's codes. Echocardiographic LVH was determined for 60 hypertensive subjects and 60 age/sex matched controls.

Hypertensive subjects had higher mean QTd than the controls (65.6 ± 28.1 ms vs 38.7 ± 11.3 ms, p< 0.0001). QTd of hypertensives with ECG LVH was significantly higher than those without ECG LVH (Araoye: 71.5 ± 22.0 ms vs 62.2 ± 24.1 ms, p = 0.02, SL; 72.0 ± 24.4 ms vs 61.6 ± 23.1 ms p = 0.009). Similarly the QTd of hypertensives with echocardiographic LVH (72.6 ± 21.3 ms) was higher than those without (60.1 ± 22.2 ms) but did not achieve statistical significance (p = 0.085).

Hypertension with or without ECG LVH is associated with significantly increased QTd. Echo-cardiographic LVH is associated with a non significant increase in QTd in hypertensive subjects.