Comparison of Incremental Shuttle Walking Test, 6-Minute Walking Test, and Cardiopulmonary Exercise Stress Test in Patients with Myocardial Infarction

Abstract

BACKGROUND This study aimed to analyze the correlations among peak oxygen uptake (VO2) in cardiopulmonary exercise test (CPX), incremental shuttle walking test (ISWT), and 6-minute walking test (6MWT) distances in patients with myocardial infarction (MI). Additionally, we aimed to determine the relationship between the maximum heart rate (HRmax) and the rate of perceived exertion (RPE) among the tests and compare the changes in heart rate to verify the clinical benefit of the submaximal stress test. MATERIAL AND METHODS We analyzed the correlation by using the ISWT and 6MWT at 30-min intervals after 24 h of CPX in patients with MI. The differences in HRmax and RPE between the tests were also compared. Additionally, changes in heart rate were analyzed using descriptive statistics. RESULTS The ISWT distance was more strongly correlated with peak VO₂ (r=.823: 95% CI, 0.681-0.910) than was 6MWT (r=0.776: 95% CI, 0.683-0.870). HRmax in the CPX demonstrated a significant correlation with that in the ISWT and 6MWT (P<0.05), with the ISWT (r=0.815: 95% CI, 0.451-0.996) having a stronger correlation than the 6MWT (r=0.664: 95% CI, 0.146-0.911). The value of RPE was significantly different (P<0.05); however, there was no significant correlation. Changes in heart rate in the 6MWT plateaued after the initial increase, while the heart rate in the ISWT and CPX increased gradually. CONCLUSIONS We recommend the ISWT as a submaximal exercise test to evaluate exercise capacity in patients with MI.

Figure 1

Incremental shuttle walking test protocol.

Figure 2

Heart rate responses to the CPX, ISWT, and 6MWT. HR – heart rate; CPX – cardiopulmonary exercise test; ISWT – incremental shuttle walking test; 6MWT – 6-minute walking test.