Features of cardiopulmonary reserve in patients with chronic thromboembolic pulmonary hypertension with concomitant rhythm disturbances

Aim. To study the characteristics of cardiopulmonary reserve in patients with chronic thromboembolic pulmonary hypertension (CTEPH) with concomitant atrial fibrillation (AF) and to evaluate the relationship between the level of peak oxygen consumption (V´О₂ peak) and the course of the hospital period after pulmonary endarterectomy Material and methods. A total of 124 male patients with CTEPH aged 52.8 (43.2–64.1) years were examined. 1st group (29 people) included patients with concomitant AF, and 2nd group (95 people) included patients without AF. Before surgery, patients underwent a cardiopulmonary exercise test (CPET). Results. According to the CPET data, in the 1st group the values of V´О₂ peak, V´О₂ peak at the anaerobic threshold, V´О₂/HR peak, threshold power and duration of physical activity (PA) were lower in comparison with the 2nd (p<0.05). The ventilatory equivalent for carbon dioxide (V´E/V´CО₂ peak) in the 1st group was higher than in the 2nd (p<0.05). Tolerance to PA in the 1st group was also lower in comparison with the 2nd group due to the lower threshold power and shorter duration of the load (p<0.05). V´О₂ peak values are inversely associated with the development of heart failure (OR 0.56 (0.36-0.82; p=0.002)), prolonged mechanical ventilation (OR 0.43 (0.34-0.71; p=0.001)) and hospital mortality in the early postoperative period (OR 0.82 (0.75-0.94; p=0.03)). Conclusion. Patients with CTEPH with concomitant AF are characterized by lower reserves of the respiratory and cardiovascular systems compared to patients without AF due to lower values of V´О₂ peak, V´О₂ peak at the anaerobic threshold, V´О₂/HR peak and a higher value of V´E/V´CО₂ peak. The comorbid group is characterized by lower tolerance to PA in comparison with the group without AF. V´О₂ peak values are inversely related to the development of heart failure, prolonged mechanical ventilation and hospital mortality in the early postoperative period.