Myocardial Contractility in Normal and Post Infarction Subjects at Rest and During Isometric Exercise
Interest has developed in non-invasive techniques for analyzing left ventricular function. Echocardiography is a tool currently being used in this regard. A deficiency of the technique is its inability to study myocardial function during dynamic exercise. Isometric exercise is a useful alternative to dynamic exercise and allows ultrasound examination of the left ventricle under stress. It has been studied extensively and used in several instances to study abnormal and normal left ventricular function. Isometric exercise results in the production of two cardiovascular phenomenon; an increase in heart rate and an elevation in blood pressure both of which increase myocardial oxygen demand and the work of the heart. Its simplicity of application has allowed several recent studies of isometric exercise and its effects on myocardial force velocity relations. One recent paper has been published by Stefadouros using echocardiography to determine the normal ventricular response.
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