VASOSPASTIC ISCHEMIC MECHANISM OF FREQUENT ASYMPTOMATIC TRANSIENT ST-T CHANGES DURING CONTINUOUS ELECTROCARDIOGRAPHIC MONITORING IN SELECTED UNSTABLE ANGINA PATIENTS

Asymptomatic episodes of ST segment and/or T wave changes were often reported during Holter monitoring in patients with angina pectoris. The interpretation of such changes is debated relative to silent myocardial ischemia. Patients (11) admitted because of frequent episodes of unstable anginal attacks who had undergone repeated periods of Holter monitoring, characterized by predominantly occurring asymptomatic episodes of ST segment and/or T wave changes associated with less frequent typical anginal attacks were studied. In a total of 89 days of Holter monitoring, the patients evidenced 520 episodes of transient ECG changes including 180 of ST elevation, 73 of ST depression and 267 of T wave alterations. Only 12% of episodes were symptomatic. Coronary injection during asymptomatic ST-T changes was performed in 8 patients. In 6 it was possible to document spontaneous coronary spasm. In 7 patients ergonovine administration induced anginal pain, ST-T changes and coronary spasm. In all patients the anginal attacks completely disappeared with medical treatment and the asymptomatic episodes were abolished in 6 and reduced in 4. In certain selected unstable anginal patients, transient asymptomatic ECG changes apparently are caused by acute myocardial ischemia.