Exercise and functional capacity after myocardial infarction.

This paper summarizes the literature on the effects of both inpatient and outpatient exercise programs on functional capacity in patients categorized as having mild, moderate, severe and very severe left ventricular damage after myocardial infarction (MI). Current evidence suggests that inpatient activities of daily living programs do not improve functional capacity as measured by a predischarge exercise stress test. In contrast, outpatient exercise training programs can improve functional capacity through augmentation of skeletal muscle arteriovenous oxygen difference (oxygen extraction) in nearly all patients with mild left ventricular damage, in most patients with moderate damage and in a few patients with severe damage. The recently developed conceptual model of functional capacity in post-MI patients presented in this paper underscores the need for assessment of the level of structural and functional impairment of the left ventricle before the nurse prescribes any type of exercise program. It also enables the nurse to begin to explain why post-MI patients differ in their response to exercise. Further research is needed, however, before the model can be used for predicting exercise outcomes in the clinical setting.