Safety of early performance of the six-minute walk test following acute myocardial infarction: a cross-sectional study

Highlights • Coronary artery disease (CAD) is one of the main causes of death. • The stress test is indispensable before cardiac rehabilitation. • The 6MWT is a simple, low-cost, valid, and reliable method. • The 6MWT can be used safely in the hospital after an AMI.
Background The six-minute walk test (6MWT) is a simple, low cost, reliable, and valid method for evaluating the functional capacity of cardiac patients. However, its early use and safety following acute myocardial infarction (AMI) is recent and has been little investigated. Objective To evaluate and to compare the safety and the cardiac behavior of early performance of the 6MWT in patients following uncomplicated AMI up to 4 days or more than 4 days after the event. Methods Following discharge from the Coronary Care Unit, 152 stable asymptomatic patients diagnosed with uncomplicated AMI performed the 6MWT. During the test, in addition to the distance walked, heart rate (HR), blood pressure (BP), and adverse events were also recorded. Electrocardiography was recorded using a Holter monitor in 105 patients. Patients were allocated considering two groups according to the number of days since AMI: Up to 4 Days Group and After 4 Days Group. Results All patients completed the 6MWT, 66 in the Up to 4 Days Group and 86 in the After 4 Days Group. The walking distance was similar in both groups (85% of the predicted value), as well as the physiological responses (increase in systolic BP and HR), reaching 63% (median) of maximum HR. Only 3.9% of patients had major complications (angina, drop in BP, or ventricular tachycardia), with no difference between the groups. None of the complications regarded as severe led to truly significant complications or death. Conclusion The 6MWT was proven to be safe and feasible for early functional evaluation following uncomplicated AMI.