Prognostic significance of isolated, non-specific left ventricular repolarization abnormalities in hypertension.

Abstract

Clinicians are often confronted with the incidental finding of isolated minor, non-specific repolarization changes on the electrocardiogram (ECG) in hypertensive patients. The aim of this study was to investigate the prognostic significance of such changes. Prospective, observational study. A total of 1970 hypertensive patients without prevalent cardiovascular disease were followed for up to 9.1 years (mean 4.7 years). Patients with ECG abnormalities including ischaemia, previous infarction, bundle branch block, atrial fibrillation and ventricular pre-excitation were excluded. Patients were divided into three groups: normal left ventricular (LV) repolarization (n = 1355); minor repolarization changes (n = 504); and typical LV strain (n = 111). During follow-up, 78 patients developed new-onset ischaemic heart disease. The event rates were 0.50, 1.28 and 3.08 per 100 patient-years in the groups with normal repolarization, minor changes, and typical LV strain, respectively (P < 0.001). After adjustment for the effect of age, sex, diabetes, serum cholesterol, smoking, LV hypertrophy and 24-h pulse pressure, the risk for developing coronary events was higher in patients with minor repolarization changes (hazard ratio 2.07, 95% confidence interval 1.23-3.47; P < 0.01) or LV strain (hazard ratio 4.00, 95% confidence interval 2.09-7.65; P < 0.001) than in patients with normal repolarization (reference category). Population-attributable risks were 21 and 14%, respectively. Minor ST-T changes also retained an adverse prognostic value among patients without LV hypertrophy (hazard ratio 1.90, 95% confidence interval 1.08-3.33; P = 0.026). We have identified minor, non-specific LV repolarization changes as a novel, independent risk factor for ischaemic heart disease in patients with uncomplicated hypertension.