Taisuke Nakade1, Hitoshi Adachi2, Makoto Murata3, Shigeru Oshima2. 1. Division of Cardiovascular Medicine, Department of Cardiology, Gunma Prefectural Cardiovascular Center, 3-12, Kamezumi, Maebashi, Gunma, 3710004, Japan. t.nakade.gcvc@gmail.com. 2. Division of Cardiovascular Medicine, Department of Cardiology, Gunma Prefectural Cardiovascular Center, 3-12, Kamezumi, Maebashi, Gunma, 3710004, Japan. 3. Department of Medicine and Biological Science, Graduate School of Medicine, Gunma University School of Medicine, Maebashi, Gunma, Japan.
Abstract
PURPOSE: Cardiopulmonary exercise testing (CPX) is used to evaluate functional capacity and assess prognosis in cardiac patients. Ventilatory efficiency (VE/VCO2) reflects ventilation-perfusion mismatch; the minimum VE/VCO2 value (minVE/VCO2) is representative of pulmonary arterial blood flow in individuals without pulmonary disease. Usually, minVE/VCO2 has a strong relationship with the peak oxygen uptake (VO2), but dissociation can occur. Therefore, we investigated the relationship between minVE/VCO2 and predicted peak VO2 (peak VO2%) and evaluated the parameters associated with a discrepancy between these two parameters. METHODS: A total of 289 Japanese patients underwent CPX using a cycle ergometer with ramp protocols between 2013 and 2014. Among these, 174 patients with a peak VO2% lower than 70% were enrolled. Patients were divided into groups based on their minVE/VCO2 [Low group: minVE/VCO2 < mean - SD (38.8-5.6); High group: minVE/VCO2 > mean + SD (38.8 + 5.6)]. The characteristics and cardiac function at rest, evaluated using echocardiography, were compared between groups. RESULTS: The High group had a significantly lower ejection fraction, stroke volume, and cardiac output, and higher brain natriuretic peptide, tricuspid regurgitation pressure gradient, right ventricular systolic pressure, and peak early diastolic LV filling velocity/peak atrial filling velocity ratio compared with the Low group (p's < 0.01). In addition, the Low group had a significantly higher prevalence of pleural effusion than did the High group (26 vs 11%, p < 0.01). CONCLUSIONS: Patients with a relatively greater minVE/VCO2 in comparison with peak VO2 had impaired cardiac output as well as restricted pulmonary blood flow increase during exercise, partly due to accumulated pleural effusion.
PURPOSE: Cardiopulmonary exercise testing (CPX) is used to evaluate functional capacity and assess prognosis in cardiac patients. Ventilatory efficiency (VE/VCO2) reflects ventilation-perfusion mismatch; the minimum VE/VCO2 value (minVE/VCO2) is representative of pulmonary arterial blood flow in individuals without pulmonary disease. Usually, minVE/VCO2 has a strong relationship with the peak oxygen uptake (VO2), but dissociation can occur. Therefore, we investigated the relationship between minVE/VCO2 and predicted peak VO2 (peak VO2%) and evaluated the parameters associated with a discrepancy between these two parameters. METHODS: A total of 289 Japanese patients underwent CPX using a cycle ergometer with ramp protocols between 2013 and 2014. Among these, 174 patients with a peak VO2% lower than 70% were enrolled. Patients were divided into groups based on their minVE/VCO2 [Low group: minVE/VCO2 < mean - SD (38.8-5.6); High group: minVE/VCO2 > mean + SD (38.8 + 5.6)]. The characteristics and cardiac function at rest, evaluated using echocardiography, were compared between groups. RESULTS: The High group had a significantly lower ejection fraction, stroke volume, and cardiac output, and higher brain natriuretic peptide, tricuspid regurgitation pressure gradient, right ventricular systolic pressure, and peak early diastolic LV filling velocity/peak atrial filling velocity ratio compared with the Low group (p's < 0.01). In addition, the Low group had a significantly higher prevalence of pleural effusion than did the High group (26 vs 11%, p < 0.01). CONCLUSIONS:Patients with a relatively greater minVE/VCO2 in comparison with peak VO2 had impaired cardiac output as well as restricted pulmonary blood flow increase during exercise, partly due to accumulated pleural effusion.
Entities:
Keywords:
Cardiac output; Cardiopulmonary exercise test; Peak VO2; min VE/VCO2
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