Reliability and Validity of a Self-paced Cardiopulmonary Exercise Test in Post-MI Patients

A self-paced peak oxygen uptake (V̇O_2peak) test (SPV) has been shown to produce higher V̇O_2peak values compared to standard cardiopulmonary exercise tests (sCPET), but has not been tested on any clinical population. This study aimed to assess the reliability of the SPV in a healthy population (study 1), and the validity and reliability of the SPV in post-myocardial infarction (post-MI) patients (study 2). For study 1, 25 healthy participants completed 3 SPV's. For study 2, 28 post-MI patients completed one sCPET and 2 SPV's. The SPV consisted of 5×2-min stages where participants were able to self-regulate their effort by using incremental 'clamps' in ratings of perceived exertion. The sCPET consisted of a 20 W/min ramp. Results demonstrated the SPV to have a coefficient of variation for V̇O_2peak of 4.7% for the healthy population, and 8.2% for the post-MI patients. Limits of agreement ranged between±4.22-5.86 ml·kg^-1·min^-1, with the intraclass correlation coefficient ranging between 0.89-0.95. In study 2, there was a significantly higher V̇O_2peak achieved in the SPV (23.07±4.90 ml·kg^-1·min^-1) against the sCPET (21.29±4.93 ml·kg^-1·min^-1). It is concluded that these results provide initial evidence that the SPV may be a safe, valid and reliable method for determining exercise capacity in post-MI patients.