Cardiorespiratory response and perception of exertion to the six-minute walk test in patients with acute myocardial infarction at discharge from the Intensive Care Unit

Abstract

Introduction: Acute myocardial infarction (AMI) significantly impairs patients’ functional capacity, especially during the transition from the Intensive Care Unit (ICU) to the hospital ward. The Six-Minute Walk Test (6MWT) has proven useful for early assessment of functionality. Objective: to analyze cardiorespiratory responses and perceived exertion during the 6MWT at ICU discharge in patients with AMI.
Methods: a cross-sectional study was conducted with 85 adult patients with AMI admitted to a cardiovascular ICU. Sociodemographic and clinical data, six-minute traveled distance (6MWD), physiological parameters (heart rate, systolic and diastolic blood pressure, duble product, peripheral oxygen saturation) and perceived exertion using the Modified Borg Scale were measured. Statistical analyses included paired t-tests and Pearson correlation (p<0.05). Results: the mean age was 59.4 ± 11.2 years, with a predominance of males (74.1%). The 6MWD was significantly lower than predicted (353.9 ± 85.4 m vs. 536.5 ± 50.2 m; p<0.003). A significant increase was observed in all cardivascular variables and perceived exertion after the test (p<0.001), while SpO₂ remained stable (p=0,780). Perceived exertion showed a weak negative correlation with 6MWD (r = -0.411; p<0.001). No adverse events occurred. Conclusion: the 6MWT is a safe, feasible and sensitive tool for assessing the functional capacity of AMI patients at ICU discharge. It can assist in risk stratification and guide early cardiovascular rehabilitation planning.