Reflex heart rate and blood pressure changes during ST segment elevation in patients with variant angina

Abstract

Responses of heart rate and blood pressure to transient myocardial ischemia were analyzed in patients with variant angina. Heart rate changes during ST segment elevation were examined by means of a Holter ECG monitoring system. All 27 ST segment elevations from 10 patients with anterior ischemia were accompanied by an increase in heart rate by 12 ± 2 bpm (mean ± SEM, p < 0.001) at peak ST segment elevation. With inferior ischemia in nine patients, heart rate decreased significantly by 4 ± 1 bpm (n = 28, p < 0.001). However, 9 of these 28 ST segment elevations showed a biphasic response of heart rate, that is, an initial increase and subsequent decrease. Such heart rate changes were not different between ST segment elevations with and without chest pain. With chest pain systolic blood pressure rose in anterior ischemia by 42 ± 5 mm Hg (n = 10, p < 0.001) but fell in inferior ischemia by 22 ± 8 mm Hg (n = 7, p < 0.05). We conclude that a different cardiovascular reflex occurs in response to inferior versus anterior ischemia and it is independent of chest pain.