Patients with heart failure (HF) who experience daytime upright Cheyne-Stokes respiration (CSR) were found to have worse clinical outcomes and to be at increased risk for cardiac death, according to a study published in the Journal of the American College of Cardiology.
CSR is characterized by abnormal periodic breathing with alternating phases of hyperpnea and central apnea.
A total of 574 consecutive outpatients with chronic systolic HF (left ventricular ejection fraction, 32±9%; age, 65±13 years) were enrolled in this study. Participants underwent within 2 consecutive days 2-dimensional echocardiography, 24-hour Holter recording, a cardiopulmonary exercise test, 24-hour cardiorespiratory recording, short-term respiratory monitoring with a head-up tilt test to identify upright CSR, and chemoreflex sensitivity assessment to evaluate hypercapnia and hypoxia. Cardiac death was recorded from study entry (2007 to 2018) to follow up (2019).
In this cohort, 34% of patients had supine CSR only, 14% had supine and upright CSR, and 52% had normal breathing. The only significant predictor of upright CSR was hypercapnic ventilatory response (odds ratio [OR], 3.96; 95% CI, 1.45-10.76; P =.007), which held in a multivariable analysis that used supine CSR as a reference category (OR, 4.01; 95% CI, 1.54-10.46; P =.004).
Upright CSR was associated with worse clinical outcome at the 8-year follow-up (log-rank = 14.05; P =.001) and predicted 8-year cardiac death (hazard ratio [HR], 2.39; 95% CI, 1.08-5.29; P =.032). Other significant predictors of 8-year cardiac death included moderate to severe mitral regurgitation (HR, 3.83; 95% CI, 1.83-7.98; P <.001), peak VO2/kg during a cardiopulmonary exercise test (HR, 0.89; 95% CI, 0.81-0.98; P =.017), and VE/VCO2 slope (HR, 1.05; 95% CI, 1.01-1.09; P =.01).
Limitations of the study include the lack of chemoreflex sensitivity measurement in upright and supine positions as well as the assessment of upright CSR at enrollment only.
“Additional studies are needed to clarify the pathophysiological mechanisms responsible for postural ventilatory instability in patients with [HF],” noted the study authors.
Giannoni A, Gentile F, Sciarrone P, et al. Upright Cheyne-Stokes respiration in patients with heart failure. J Am Coll Cardiol. 2020;75(23):2934-2946.