Abstract 15497: Clinical Significance of the Overshoot Phenomena of Respiratory Gas Indices During Recovery After Maximal Exercise Testing in Cardiac Patients

BackgroundOvershoot phenomena of the gas exchange ratio (R:VCO2/VO2), ventilatory equivalent for O2 (VE/VO2), and end-tidal O2 pressure (PETO2) are commonly observed during recovery from maximal cardiopulmonary exercise testing (CPX). We investigated the clinical significance of the overshoots of these indices by comparing their magnitudes between healthy subjects and cardiac patients.MethodsIn total, 372 subjects (79 healthy subjects and 293 cardiac patients) who underwent CPX and achieved peak R ≥ 1.10 were enrolled. We evaluated and calculated the presence and magnitude of the overshoot phenomena of R, VE/VO2, and PETO2.ResultsThe overshoot phenomena of R, VE/VO2, and PETO2 were observed in almost all the subjects. The magnitudes of the R (26.5±12.0 vs 29.9±10.2%, p=0.012), VE/VO2 (61.2±27.8 vs 78.8±29.5%, p