Rational sequence toward the diagnosis of myocardial ischemia.
The technological progress in cardiovascular investigation and the recent advances in our understanding of both the pathophysiology of myocardial ischemia and the natural course of ischemic heart disease have challenged the classical diagnostic approach toward myocardial ischemia based on symptoms and short-lasting electrocardiographic recordings. In fact, one must consider that: ischemia may be asymptomatic; coronary atherosclerosis is not the only cause of ischemia and may coexist with normal perfusion even during strenuous exercise while functional factors may reduce coronary blood flow; old and new "markers" of ischemia are affected by a relatively low sensitivity and specificity; the disease course has unpredictable short and long-term variations. The main goals in the diagnostic process are the identification in each patient of the organic and functional factors inducing ischemia and the evaluation of their role in cardiac damage, performance and prognosis. Since the reduction in 'organic' coronary reserve, as usually assessed by exercise stress test, can be overestimated by a functional increase in coronary tone (fixed vs dynamic stenosis), the idea of repeated tests or of a reference test during therapy with nitrates or calcium antagonists has been conceived. Transient functional increase in coronary resistance can be indirectly estimated by comparing cardiac work during spontaneous or provoked ischemia with the reference exercise ischemic threshold; increases in heart rate and/or blood pressure before or during ischemia do not exclude a primary reduction of coronary blood flow unless they reach the reference value of coronary reserve.(ABSTRACT TRUNCATED AT 250 WORDS)
D000787:Angina Pectoris / Q000175:diagnosis / Q000503:physiopathology; D001794:Blood Pressure; D003326:Coronary Circulation; D003327:Coronary Disease / Q000175:diagnosis* / Q000503:physiopathology; D003331:Coronary Vessels / Q000503:physiopathology; D004562:Electrocardiography; D005080:Exercise Test; D006339:Heart Rate; D006801:Humans