Rest and exercise hemodynamic and metabolic findings in active duty soldiers referred for cardiac catheterization to exclude heart disease: Insights from past invasive cardiopulmonary exercise testing using multisensor high fidelity catheters

Objective: This study describes results of iCPET from the past, which used submaximal stress and multisensor high-fidelity catheters to exclude heart disease in a unique population of young adults. Background: There has been resurgence in comprehensive hemodynamic evaluation of complex cardiovascular patients. Although dynamic assessments during cardiac catheterization have become commonplace, there remains limited information regarding left and right heart hemodynamic changes during supine exercise in young adults. Methods: The study population was derived from a retrospective review of catheterization records at Brooke Army Medical Center for active duty patients (ages: 19–40 years) in whom hemodynamic waveforms were obtained with multisensor high-fidelity catheters and supine exercise testing (53.1 ± 12.6 watts) and angiography performed to exclude heart disease. We report findings from 41 males and 1 female (ages: 19–40 years) found free of heart disease. Results: Submaximal exercise was associated with ≈ fourfold (P < 0.001) increase in minute ventilation (VE), O₂ consumption (VO₂) and carbon dioxide production (VCO₂). VE/VCO₂ ratio decreased (−16.8 ± 13.9%, P < 0.001) and VE/VCO₂ slope was 22.6 ± 0.6 (±SE). Cardiac index (CI) increased with VO₂ (ΔCI/ΔVO₂ slope = 7.6 ± 2.2). Heart rate increased nearly 10 bpm per 100 mL O₂/min/M², whereas, changes in stroke volume were more variable. Pulmonary artery (PA) saturations fell from 77 to 55% (P < 0.001). No change was noted in mean right atrial pressures; PA pressures increased ≈10 mm Hg (P < 0.001). Pulmonary capillary wedge and left ventricular end-diastolic pressures increased ≈2 mm Hg (P < 0.001) but variability noted between individuals. Conclusion: This study provides insight into past practices of invasive cardiopulmonary testing and furthers the understanding of metabolic and hemodynamic changes in a young population during supine submaximal exercise.