Internal medicine
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Observational Study
Cardiac Acoustic Biomarkers in Patients with Heart Failure during Cardiopulmonary Exercise Testing: An Exploratory Study.
Objective Exercise therapy as part of cardiac rehabilitation is one of the most effective treatments for patients with chronic heart failure (HF). The anaerobic threshold (AT) determined by an exhaled gas analysis during cardiopulmonary exercise testing (CPX) is used to prescribe the appropriate level of exercise therapy. However, CPX using an exhaled gas analysis is not widely performed because of its cost, complexity, and the need for skilled staff. ⋯ Results A significant correlation (R=0.70; p<0.001) was found between CPX-AT and CAB-AT, using the double product of S1 intensity and heart rate. CAB-AT using S1 intensity also showed a significant correlation with CPX-AT (R=0.71; p<0.001). Conclusion The present study suggests a possible new method for determining AT without respiratory gas measurements in patients with HF.