Cheyne-Stokes respiration related oscillations in cardiopulmonary hemodynamics in patients with heart failure

Background: Although Cheyne-Stokes respiration (CSR) is an oscillatory phenomenon, the direct effects of cyclical hyperventilation and apnea on cardiopulmonary hemodynamics have been poorly investigated. The aim of the study was to examine the echocardiographic changes associated with CSR phases in a group of patients with systolic heart failure (HF) and daytime CSR. Methods: 14 HF patients (age 70 ± 9 years, LVEF 24 ± 5) underwent a thorough clinical evaluation, 24-h respiratory polygraphy, chemoreflex evaluation by rebreathing technique and neuro-hormonal assessment. Furthermore, they received a simultaneous echocardiographic and respiratory monitoring embedding the respiratory signal in the echocardiographic machine. Results: All patients had daytime CSR (diurnal apnea-hypopnea index, AHI: 18.5, interquartile range: 15.3-39.5 events/h). Systolic pulmonary artery pressure and pulmonary vascular resistances (PVR) increased from hyperventilation to apnea (H 45.3 ± 11.4 vs A 52.4 ± 13.8 mmHg, p = 0.004, and H 3.3 ± 2.5 vs A 5.1 ± 3.2 Wood units, p = 0.0003, respectively), while acceleration time of the pulmonary artery decreased (H 110.1 ± 19.8 vs A 92.0 ± 19.9 ms, p = 0.001). During apnea a reduction of right and left ventricular outflow tract VTI (H 12.8 ± 4.9 versus A 9.9 ± 3.1, p = 0.002 and H 26.9 ± 8.8 versus A 22.8 ± 7.9 mm, p = 0.006, respectively), and a reduction in tricuspid annular plane systolic excursion (H 15.9 ± 4.4 versus A 14.4 ± 4.1 mm, p = 0.005) were also observed. Notably, PVR variation strongly correlated with chemosensitivity to hypercapnia (R = 0.89, p = 0.0004) and plasma norepinephrine level (R = 0.78, p = 0.003). Conclusions: In HF patients with CSR, an increase in pulmonary pressure and pulmonary vascular resistances was observed during apnea. Pulmonary vasoconstriction strongly correlated with chemosensitivity to hypercapnia and indexes of adrenergic activation.