title: Assessment of myocardial stress from early ambulatory activities following myocardial infarction.
abstract: Little is known of the magnitude of the stress imposed on the heart by ambulatory activities following infarction. Heart rate, blood pressure, and rhythm provide simple and important estimates of these potential stresses. We therefore measured these variables in 32 patients during sitting, standing, and walking in the first two days following myocardial infarction. Ambulatory activities caused only a small increase in heart rate, with a maximum increase of 9 beats/minute during walking. The blood pressure was either unchanged or decreased during activity. In six other patients, we also measured central hemodynamics during the same activities. The wedge pressure fell with sitting and standing and remained low after walking. All activities were well tolerated. The major problem was hypotension; this was associated with chest pain in one patient, dizziness in four and shortness of breath in two. Most of the patients with hypotension were taking nitrates. In conclusion, mild ambulatory activities produce little stress for the myocardium and can be permitted in the first few days following infarction as long as blood pressure is measured.
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D004434:Early Ambulation; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology* / Q000534:rehabilitation; D011187:Posture; D013318:Stroke Volume