Symptoms and signs of myocardial ischemia

Abstract

A transient regional imbalance between oxygen supply and demand usually results in myocardial ischemia, the signs and symptoms of which can be used as a diagnostic tool [1]. Myocardial ischemia results in a typical “cascade” of events in which the various markers are hierarchically ranked in a well-defined time sequence [2]. Flow heterogeneity, especially between subendocardial and subepicardial perfusion, is the forerunner of ischemia, followed by metabolic alterations, diastolic dysfunction, induced systolic dysfunction, and only at a later stage electrocardiographic changes, global left ventricular dysfunction, and pain (Fig. 3.1). The ideal marker of ischemia should provide absolute values of sensitivity and specificity, as well as a diagnosis of the site and severity of ischemia, an accurate prediction of the patient’s outcome and reliable guidance in the decision-making process. Unfortunately, such a marker does not exist; in contrast, we have a number of imperfect markers that if associated can provide a reasonably good noninvasive estimation of the presence, extent, and severity of myocardial ischemia. The pathophysiological concept of the ischemic cascade is translated into a gradient of sensitivity of different available clinical markers of ischemia, with chest pain being the least sensitive and regional malperfusion the most sensitive.