Effect of Continuous Positive Airway Pressure on Mitral Regurgitant Fraction and Atrial Natriuretic Peptide in Patients With Heart Failure

Objectives. We sought to determine the effects of continuous positive airway pressure (CPAP) on mitral regurgitant fraction (MRF) and plasm atrial natriuretic peptide (ANP) concentration in patients with congestive heart failure (CHF). Background. In patients with CHF, elevated plasm ANP concentration is associated with elevated cardiac filling pressures. Secondary mitral regurgitation may contribute to elevation in plasm ANP concentration in patients with CHF. Because CPAP reduces transmural cardiac pressures and left ventricular (LV) volume, we hypothesized that long-term CPAP application would decrease the MRF and plasm ANP concentration in patients with CHF and Cheyne-Stokes respiration with central sleep apne (CSR-CSA). Methods. Seventeen patients with CHF and CSR-CS underwent baseline assessments of plasm ANP concentration and left ventricular ejection fraction (LVEF) and MRF by radionuclide angiography. They were then randomized to receive nocturnal CPAP plus optimal medical therapy (n = 9) or optimal medical therapy alone (n = 8) for 3 months and were then reassessed. Results. In the CPAP-treated group, LVEF increased from (mean ± SEM) 20.2 ± 4.2% to 28.2 ± 5.3% (p < 0.02); MRF decreased from 32.8 ± 7.7% to 19.4 ± 5.5% (p < 0.02); and plasm ANP concentration decreased from 140.9 ± 20.8 to 103.9 ± 17.0 pg/ml (p < 0.05). The control group experienced no significant changes in LVEF, MRF or plasm ANP concentration. Among all patients, the change in plasm ANP concentration from baseline to 3 months correlated significantly with the change in MRF (r = 0.789, p < 0.0002). Conclusions. In patients with CHF, CPAP-induced reductions in MRF and plasm ANP concentration in association with improvements in LVEF indicate improved cardiac mechanics. Our findings also suggest that reductions in plasm ANP concentration were at least partly due to reductions in MRF.