Abstract 15357: Washout Rate of 123I-Metaiodobenzylguanidine and Dose of Carvedilol are Independently Associated With Central Sleep Apnea in Chronic Heart Failure
Background: Central sleep apnea (CSA) is observed in 20 - 40% of patients with chronic heart failure (CHF) and is associated with increased morbidity and mortality in those patients. The genesis of CSA in CHF is not fully understood, but sympathetic nervous activation, which can enhance central chemosensitivity to CO2 and thereby decrease PaCO2 reserve, may play a major role in the occurrence of CSA in CHF. In the present study, we examined whether the cardiac washout rate (WR) of 123I-metaiodobenzylguanidine (123I-MIBG), a useful index of cardiac sympathetic nervous activity, and the dose of carvedilol, a beta-blocker, are associated with CSA in patients with CHF.
Methods: We prospectively performed full polysomnography and cardiac 123I-MIBG scintigraphy in 82 patients with stable CHF (NYHA functional class II/III and left ventricular ejection fraction <50%). CSA was defined as apnea-hypopnea index =15 with predominantly central apneic events. The cardiac WR of 123I-MIBG was obtained from initial (15 min) and delayed (4 h) planar 123I-MIBG images.
Results: Patients with CSA (n = 23) had a significantly higher WR than those without it (n = 59) (54.1 ± 11.3% vs 40.3 ± 10.1%, p <0.001). The dose of carvedilol was significantly smaller in patients with CSA than in those without it (3.8 ± 4.9 mg/day vs 9.6 ± 6.4 mg/day, p <0.001). Univariate logistic regression analyses showed that NYHA functional class, plasma brain natriuretic peptide, PaCO2, and left ventricular ejection fraction also were significantly associated with CSA. A multivariate logistic regression analysis selected the WR (Odds ratio 1.12, 95% confidence interval 1.03 - 1.21) and the dose of carvedilol (Odds ratio 0.83, 95% confidence interval 0.71 - 0.98) as independent variables associated with CSA.
Conclusions: The WR and the dose of carvedilol are independently associated with CSA in patients with CHF, suggesting that sympathetic nervous activation may be a major predisposing factor for CSA in CHF and that the sufficient suppression of the activated sympathetic nervous system may be important in the treatment of CSA in CHF.
- © 2010 by American Heart Association, Inc.