Relationship of electrocardiographic repolarization measures to echocardiographic left ventricular mass in men with hypertension

OBJECTIVE: Arterial hypertension often leads to an increase in left ventricular mass (LVM). Marked left ventricular hypertrophy (LVH) is associated with potentially arrhythmogenic ventricular repolarization abnormalities, which may contribute to the increased risk of sudden cardiac death in this disorder. We studied whether electrocardiographic repolarization changes are already detectable in mild LVM increase associated with hypertension. METHODS: In 220 men (mean age 51+/-6 years) attending the GENRES hypertension study, we measured QT intervals (QTend and QTpeak), T-wave peak to T-wave end (TPE) intervals, and novel T-wave morphology parameters (principal component analysis ratio, T-wave morphology dispersion, total cosine R-to-T, and T-wave residuum) from a digital standard 12-lead electrocardiogram, and related them to echocardiographically determined LVM. RESULTS: In this group of moderately hypertensive men, the mean LVM index (LVMI; LVM divided by body surface area) was 99+/-19 g/m2, with only 18% of the subjects showing evidence of echocardiographic LVH (LVMI>116 g/m2). LVMI correlated significantly with QT intervals (r=0.16-0.21, P=0.018-0.002), TPE intervals (r=0.23-0.27, P<0.001), and T-wave morphology parameters (r=0.22-0.39, P<0.001). Except for the QTpeak interval, the relationship between LVMI and electrocardiographic repolarization parameters was independent in multivariate analyses. CONCLUSION: Altered electrocardiographic ventricular repolarization, indicating reduced repolarization reserve and possibly increased repolarization heterogeneity, is already present in hypertensive men with only mild LVM increase. At a population level, this may carry important risk implications for the large group of hypertensive patients.