EXERCISE TOLERANCE TESTS ON PATIENTS WITH MYOCARDIAL INFARCTION

Abstract

The cardiac function of the patients with myocardial infarction was examined by the quantitative exercise tolerance test with an ergometer at discharge. Results of the tests were compared with clinical findings in the acute stages and clinical records during their hospitalization.52 male patients with average age of 58, who were admitted due to acute myocardial infarction, were examined in this study. At the time of discharge, an intermittent multiple load test (25W, 50W, 75W and 100W for five minutes each) was conducted using a bicycle ergometer in the upright position. ST changes of more than 2mm compared to the level at rest, frequent extrasystoles, and appearances of marked arrhythmias on the electrocardiographic recordings were the criteria for discontinuation of loading. Subjective symptoms as the criteria for discontinuation included appearance of chest pain, dyspnea, or high degree of fatigue in legs. Clinical findings in their acute stages and clinical records during their hospitalization were compared and examined in relation to the results of exercise tolerance test for each case aforementioned.The maximum physical work capacity (max. P. W. C.) at discharge, that was at around ten weeks after the attack of myocardial infarction, was 25W for 18 of 52 cases (group I), 50W for 18 cases (group II), and 75W or higher for 16 cases (group III), being almost equally divided to one third. Tests with 100W loading were performed in 9 cases in the group III, showing 3 cases with max. P. W. C. of 75W, and 6 cases with max. P. W. C. of 100W or higher.Groups with poor cardiac function at discharge were composed of cases with old age, extensive infarction, reattack, heart failure, arrhythmia, or with interfering factors for rehabilitation.Durations of bed rest were 30, 23, and 17 days for group I, II, and III, respectively. Periods of hospitalization were 86, 68, and 51 days for these groups, respectively. Both were apparently longer in groups with poorer cardiac function.Young patients, patients with limited infarction, or initial attack, or with good clinical findings, or without interfering factors for rehabilitation showed good cardiac function despite of relatively short period of hospitalization. Early mobilization and discharge after myocardial infarction should be recommended to such cases.