Invasive exercise testing.

The normal hemodynamic response to dynamic supine exercise embodies the following features: progressive increase in heart rate relative to the work intensity; an increase in cardiac output of 600 ml or greater for every 100-ml increment in oxygen consumption; minimal increase in stroke volume; a progressive increase in oxygen extraction, attaining near-maximal levels during moderate exercise; and a minimal increase in left ventricular end-diastolic, pulmonary capillary wedge, pulmonary arterial, and right ventricular end-diastolic pressures. In heart disease, the major purpose of invasive exercise testing is to assess cardiac functional reserve capacity. An evaluation of the degree of encroachment on cardiac reserve by disease processes establishes hemodynamic correlates of clinical symptomatology and aids in selecting the proper therapeutic modality for each individual patient. In patients with ischemic heart disease, preliminary evidence indicates that invasive exercise testing in conjunction with angiographic findings may contribute additional substantial prognostic information.