Clinical detection of myocardial ischemia

Myocardial ischemia involves several pathophysiologic mechanisms. To assess suspected myocardial ischemia in relation to obstructive coronary artery disease (CAD)—the most frequent case—the reference test would be an electrocardiogram (ECG) exercise stress test; in the event of inconclusive results, an imaging (either radionuclide or echocardiographic) stress test can be indicated. Pharmacologic stress tests with imaging are indicated in patients unable to exercise. The same tests can be applied in patients with suspected microvascular angina; in such patients, a diagnostic clue would be induced angina and ECG changes in the absence of regional wall motion abnormalities on echocardiographic stress testing. Spasm provocation tests using either acetylcholine or ergonovine might be necessary to detect myocardial ischemia in patients in whom this is caused by coronary epicardial, or even microvascular, spasm. ECG Holter monitoring can be helpful to identify and characterize myocardial ischemic episodes that occur during daily life.