Early Exercise Testing and Mobilization After Myocardial Infarction

The practice of rapid mobilization after myocardial infarction has left us with a necessity to (i) define the low-risk patient after myocardial infarction; (ii) define his individual physical capacity early after infarction; (iii) discover the usual rate of recovery of exercise tolerance after infarction; and (iv) advise the individual along these lines. The low-risk patient can be defined on the fourth day after admission as one with a first myocardial infarct, without continued or recurrent chest pain, cardiomegaly, cardiac failure, electrical instability, pericarditis or other adverse features, and with a creatine phosphokinase (CPK) level below 500 units. Thirty (16%) of 189 consecutive patients with myocardial infarction who were admitted to the coronary care unit met these criteria, and were submitted to a symptom-limited exercise test eight days after admission to hospital. The 24 patients without a history of angina antecedent to their infarction achieved 87% of the exercise tolerance of Australian norm, while those with prior stable angina stopped at a lower workload, heart rate, and systolic blood pressure. Eighteen of the patients without a history of angina underwent serial exercise tests at one and five weeks after admission to hospital. Exercise duration on the bicycle increased by 18% from the first to the fifth week after infarction (P < 0.001). This was accompanied by an increase in maximum heart rate from 135·6 to 153·9 beats/min (P < 0·001) without changes in the resting or submaximal heart rate, or systolic blood pressure. Early exercise testing proved useful in providing guidelines for return to most work, leisure, and sexual activities within four weeks of admission to hospital, and in predicting future clinical angina pectoris. We recommend it as an integral part in the rehabilitation of these patients.