Increased prevalence of abnormal signal-averaged electrocardiograms in older patients who have hypertension with low diastolic blood pressure.
Greater mortality in hypertensive patients with the lowest diastolic blood pressure (DBP) values has been reported and may be partially explained by more fatal arrhythmias. The records of 135 patients were reviewed to determine whether the prevalence of an abnormal signal-averaged electrocardiogram (SAECG+), a risk marker for ventricular arrhythmias, was greater in patients who have hypertension with DBP < 85 mm Hg. SAECG+ was present in 31 (39%) of 80 patients with hypertension and 13 (24%) of 55 subjects with normotension p < 0.05. Hypertensive patients were more likely than normotensive subjects to have left ventricular hypertrophy (LVH, p = 0.01) and LV dysfunction (p < 0.01). In multivariate analysis only age and systolic dysfunction emerged as significant predictors of SAECG+. Among 68 hypertensive patients and for whom recent DBP data were available, SAECG+ was present in 18 of 37 with DBP < 85 mm Hg (group 1), 1 of 12 with DBP 85 to 94 mm Hg (group 2, p < 0.05 vs group 1), and 4 of 19 with DBP > 95 mm Hg (group 3, p < 0.05 vs group 1, p = 0.08 vs group 2). There were no significant differences between the three groups of hypertensive patients for coronary artery disease, LVH, systolic dysfunction, or left-sided cardiac chamber enlargement. Multivariate analysis in hypertensive patients indicated that age and DBP were each independently predictive of SAECG+, whereas the indexes of heart disease were not. Within group 1, those with SAECG+ were significantly older (68 +/- 1 vs 59 +/- 1 years, p < 0.01) and more likely to have LVH (p < 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)