Exercise echocardiography in the evaluation of left ventricular function

pp 239-246

Abstract

Exercise echocardiography is based on three assumptions:1) exercise-induced ischemia will led to ventricular wall dyssynergy; 2) regional abnormalities are specific for ischemia, and 3) the motion changes can be accurately recorded by echocardiography. Isotonic or isometric exercise may be used. When employing digital recording, only a single high quality cardiac cycle is needed to create a cine loop; digital techniques affect also favor-ably the storage, retrieval and display of exercise echo-cardiograms. Parallely, exercise Doppler represents an additional tool that permits global left ventricular function assessment. Stroke volume is calculated from flow velocity integral times aortic valve area, and simple measurements of peak flow velocity before and after stress reflect the increase of stroke volume during exercise. These calculations are independent of ventricular geometry. The systolic pressure/volume ratio is another important global index. It is load-independent and exercise/rest values in normal subjects are at least 145 %. Besides its usefulness in coronary artery disease, stress echocardiography was employed in the evaluation of myocardial sarcoidosis, exertional hypotension and the athlete's heart, and further use in non coronary heart disease was suggested. Exercise echocardiography represents a sort of blend between ultrasound and stress testing, providing useful diagnostic information which is analogous and sometimes even better that nuclear techniques.