SUMMARYSleep-disordered breathing (SDB) is frequently observed in patients with congestive heart failure. Recent studies have shown that SDB negatively affects the onset of congestive heart failure; however, no studies have addressed the relationship between the level of SDB and the onset time of acute dyspnea. We hypothesized that SDB affects the acute onset time of dyspnea (AOT) and investigated the relationship between SDB and AOT.We examined 80 patients (mean age, 61.6 years) with congestive heart failure in a clinically stable condition. AOT was divided into 5 time periods (0:00 -6:00, 6:00 -12:00, 12:00 -18:00, 18:00 -24:00, and unknown). The apnea-hypopnea index (AHI) was obtained based on the results of polysomnography (PSG) to evaluate the severity of SDB.Acute dyspnea occurred in 59 (73.7%) of the 80 patients. When we divided the patients into an AHI < 5 group and an AHI ≧ 5 group, there was no significant difference in the AOT; however, a significant difference was observed in those divided into AHI < 20 and AHI ≧ 20 groups (P < 0.001). The patients with AHI ≧ 20 had more acute dyspnea between 18:00 -24:00 and between 0:00 -6:00 than those with AHI < 20 (32% and 19%, and 4.1% and 4.1%, respectively).Severe SDB patients tended to have acute dyspnea between midnight and dawn. The results suggest SDB might be one of the risk factors of heart failure. (Int Heart J 2008; 49: 471-480) Key words: Sleep apnea, Heart failure, Circadian rhythm SLEEP-disordered breathing (SDB) is a condition characterized by repeated episodes of apnea and hypopnea events during sleep. Sleep apnea syndrome (SAS) is defined as SDB with 30 or more apnea events including a minimum 10 second reported that OSAS patients are at 2.38 times higher risk for the onset of heart failure and OSAS is defined as an independent prognostic factor of heart failure. Sympathetic nerve activity is augmented and blood pressure is elevated gradually before waking up. In patients with SDB, the onset time of heart diseases is estimated to be between midnight and dawn. In 1995, Franklin, et al 2) reported that SDB might affect hypoxemia and ST changes, thus resulting in the onset of angina pectoris during the night. To date, no study has reported a relationship between SDB in patients with congestive heart failure and the acute onset time of heart failure. Angiotensin converting enzyme (ACE) inhibitors and β-blockers are generally administered to patients with heart failure. Recently, the prevention of heart failure has gained broad attention. If many patients with SDB suffer from heart failure between midnight and dawn, the development of an appropriate SDB treatment could possibly prevent such events. This study investigated the severity of apnea in patients with congestive heart failure and evaluated the relationship between SDB and acute onset time.
METHODSSubjects: This retrospective study was conducted in 80 consecutive patients with congestive heart failure who were admitted to St. Marianna University School of Medicine Hospital, Kawasaki, Jap...