The simple method for predicting metabolic equivalents using heart rate in patients with cardiovascular disease

Metabolic equivalents Heart rate Cardiovascular diseaseExercise capacity is an important index to assess exercise stress in cardiac rehabilitation patients.Exercise capacity is generally expressed in units of metabolic equivalents (METs) calculated during cardiopulmonary exercise testing (CPX) using a ventilatory expired gas analysis system.While guidelines of academic association recommend conducting CPX to calculate METs [1,2], CPX induces heavy exercise stress and requires the use of equipment such as a cycle ergometer and treadmill, which is not always feasible in frail elderly patients or those with unstable circulation dynamics.The present study explored the possibility of predicting METs during exercise from heart rate (HR) of patients with cardiovascular disease.A total of 251 patients aged ≥18 years underwent CPX at the cardiac rehabilitation center of our hospital on an outpatient basis between April 2012 and August 2017.Of these, 243 patients with ischemic heart disease, valvular disease, and/or heart failure were included in this study.Patients with atrial fibrillation, implanted cardiac pacemakers or ventricular assist devices, and a history of orthopedic conditions or cerebrovascular diseases were excluded.