Washout Rate of Cardiac Iodine-123 Metaiodobenzylguanidine is High in Chronic Heart Failure Patients With Central Sleep Apnea

Abstract

Background The association between sleep-disordered breathing (SDB) assessed by polysomnography and cardiac sympathetic nerve activity (SNA) assessed by cardiac iodine-123 metaiodobenzylguanidine (123I-MIBG) imaging has not been investigated in patients with chronic heart failure (CHF). Methods and Results We performed cardiac 123I-MIBG scintigraphy and overnight polysomnography in 59 patients with stable CHF. The patients were classified into the 3 groups: 19 with no or mild SDB (NM-SDB, apnea-hypopnea index <15); 21 with central sleep apnea (CSA), and 19 with obstructive sleep apnea (OSA). The cardiac washout rate (WR) of 123I-MIBG was obtained from initial and delayed planar 123I-MIBG images. The WR was higher in patients with CSA (54.2 ± 11.6%) than in those with OSA (37.9 ± 8.6%, P < .05) or NM-SDB (40.8 ± 8.8%, P < .05). The WR correlated positively with central apnea index (ρ = 0.40, P = .002). A stepwise multiple regression analysis selected CSA and plasma brain natriuretic peptide levels as independent variables associated with the WR. Conclusions The WR was higher in CHF patients with CSA than in those with OSA or NM-SDB, and CSA was independently associated with the WR, suggesting a link of CSA to increased cardiac SNA in CHF.