Five patients with variant angina showed alternating ST-segment elevation and contralateral ST-segment depression between the precordial and inferior leads in electrocardiographic recordings made during sequential anginal attacks. This electrocardiographic "seesaw" phenomenon was observed during ergonovine-induced attacks in 3 cases and during spontaneous attacks in 1 case. Another patient showed ST-segment elevation in a spontaneous attack and in other leads during hyperventilation. In all cases, the first attack was accompanied by ST-segment elevation in the inferior leads. Coronary arteriography demonstrated that in all cases, coronary arterial spasm occurred during the attacks in both coronary arterial systems. Significant organic coronary arterial stenoses (> 50%) were found in both the left anterior descending branch and the right coronary artery in 2 patients. The remaining 3 patients showed no significant organic stenoses in any major coronary artery. However, pre-anginal coronary arteriography demonstrated that 13 of the 15 major coronary arteries, including all 9 of the major coronary arteries in the patients without significant stenoses, were already spastic. An exercise stress test performed in the morning induced attacks with chest pain and electrocardiographic ST-segment elevation in all 5 patients. The patients having an alternate ST-segment elevation in separate leads had vasospastic tendencies in both coronary arterial systems.