Hemodynamic responses to isometric handgrip exercise at 30% maximal voluntary contraction and to maximal symptom-limited cycle exercise were analyzed in 90 patients, who had New York Heart Association functional classes I and II 21 to 65 days after acute myocardial infarction. Neither angina, electrocardiographic changes, nor symptoms or signs of heart failure occurred during handgrip exercise, whereas each did, in some cases, during cycle exercise. Both handgrip and dynamic exercise produced significant cardiovascular activation; in particular, stroke volume decreased and total systemic resistance increased during handgrip, whereas they behaved in an opposite manner during cycle exercise. Left ventricular stroke work index was not increased during handgrip even in persons with a normal response to this test (change in pulmonary wedge pressure [PWP] >m 4 mm Hg). Resting PWP was normal (ltm12 mm Hg) in 79% of the patients. It increased normally during both dynamic (<m20 mm Hg) and handgrip exercise in 35% and responded abnormally to both types of work in 30%, whereas it was normal only during handgrip exercise in 18% and only during dynamic exercise in 17%. A PWP greater than 16 mm Hg during handgrip exercise was predictive (96%) of abnormal response to dynamic exercise. Correlations were not found between invasive (PWP and cardiac index) and noninvasive (rate-pressure product) recordings during handgrip exercise. In patients with myocardial infarction, the hemodynamic responses to handgrip and to dynamic exercise are qualitatively and quantitatively different; a normal PWP during handgrip work does not indicate normal left ventricular function; handgrip exercise is not a useful detector of myocardial ischemia or arrhythmias in patients with uncomplicated infarction.
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