Breathing pattern and pulmonary gas exchange in elderly patients with and without left ventricular dysfunction - modification with exercise-based cardiac rehabilitation and prognostic value

Aims In elderly patients with and without left ventricular dysfunction (LVD) we compared ventilatory parameters from before to after exercise-based cardiac rehabilitation (exCR) and assessed their prognostic value for major adverse cardiovascular events (MACE). Methods and Results Patients aged ≥65 years with acute or chronic coronary syndromes (ACS, CCS) without cardiac surgery who participated in a multicentre study on effectiveness of exCR from seven European countries were included. Cardiopulmonary exercise testing (CPET) was performed before, at termination of exCR and at 12 months follow-up. Ventilation (VE), breathing frequency (BF), tidal volume (VT) and end-expiratory carbon dioxide pressure (P ET CO 2 ) were measured at rest, at first ventilatory threshold and peak exercise. In 818 patients, age was 72.5±5.4 years, 21.9% were women, 79.8% had ACS, and 151 (18%) had LVD. NYHA functional class was not different between LVD and noLVD (86% NYHA I in each group). Compared to noLVD, in LVD resting VE was increased 8%, resting BF 6%, peak VE, peak VT, and peak P ET CO 2 reduced by 6%, 8%, and 5%, respectively, and VE/VVCO 2 slope increased by 11%. From before to after exCR, resting VE decreased and peak P ET CO 2 increased significantly more in LVD compared to noLVD. In LVD, higher resting BF, higher nadir VE/VCO 2 , and lower peak P ET CO 2 at baseline were associated with MACE Conclusions In elderly patients with ischemic LVD, exaggerated resting ventilation and impaired pulmonary gas exchange during exercise was related to worse outcomes. ExCR was associated with an improvement of abnormal breathing patterns and gas exchange parameters.