Usefulness of simultaneous ambulatory electrocardiographic and blood pressure monitoring in detecting myocardial ischemia in patients > 70 years of age with systemic hypertension.

Ischemic-type ST-segment depression is frequently observed in younger hypertensive patients. To assess the frequency of ST-segment depression in elderly hypertensive patients and to determine the influence of heart rate (HR) and blood pressure (BP) on the episodes of transient myocardial ischemia, ambulatory electrocardiographic and BP monitoring was simultaneously performed in 41 untreated hypertensive patients > 70 years of age (mean age 79 +/- 6 years; office BP > or = 160/95 mm Hg). A total of 66 episodes of significant ST-segment depression (> or = 0.1 mV, duration > or = 1 minute, interval > or = 1 minute) could be demonstrated in 15 patients (37%); 26 patients (63%) had no ST-segment changes. The 2 groups did not differ in age, gender, office or ambulatory BP, diurnal BP profile, concomitant diseases, ventricular arrhythmias, or in left ventricular (LV) mass or function. In 11 patients with ST-segment depression (73%), an increase in HR of > 15% preceded the episodes of ST-segment depression; 2 of these patients (13%) had an additional increase in BP of > 20/10 mm Hg. The extent of ST-segment depression was correlated significantly to BP, HR and HR x systolic BP product during the ischemic events, to office BP, and to LV mass. In conclusion, transient myocardial ischemia is a frequent phenomenon in elderly hypertensive patients with and without LV hypertrophy. Whereas most episodes of ischemia are preceded by an increase in HR, the extent of ST-segment depression is dependent on HR, BP and LV mass.