N. Chapman et al., QT intervals and QT dispersion as measures of left ventricular hypertrophyin an unselected hypertensive population, AM J HYPERT, 14(5), 2001, pp. 455-462
Electrocardiographic (ECG) QT intervals and dispersion correlate with echoc
ardiographic left ventricular mass index (LVMI) in groups of selected essen
tial hypertensives. We tested the strength of this relationship in a large
group of unselected hypertensives to assess whether QT measurements may be
a simple screening test for LVH in clinical practice. In a cross-sectional
study of 386 un selected hypertensive subjects, maximal QT intervals (QT(ma
x)), QT dispersion (QT(disp)), and ECG voltages (Sokolow-Lyon and Cornell s
ex-specific voltages) were measured from 12-lead EGG. The LVMI correlated m
ost strongly with Cornell voltage (linear regression r = 0.44, P < .001). T
he strongest relationship between LVMI and VT parameters was with QT(max),
(r = 0,25, P < .001), This relationship weakened using heart rate-corrected
QT(max). Correlations between LVMI and QT(disp) were weak, whether or not
they were corrected for heart rate. Sokolow-Lyon voltages, Cornell voltage
and QT(max), but not QT(disp), were independently predictive of LVMI after
adjustment for age, sex, race, and the other ECG parameters. Receiver opera
ting characteristic (ROC) curve analyses demonstrated that no QT parameter
performed better than simple ECG voltage criteria in the detection of LVH.
In conclusion, QT(max), the QT parameter most strongly associated with LVMI
, was independently associated with LVMI after adjustment for standard ECG
voltage criteria. However, as an isolated measure it was no better than sim
ple ECG voltage criteria as a screening test for LVH in clinical practice.
(C) 2001 American Journal of Hypertension, Ltd.