Patients with HF and unsuppressed CSA despite receiving CPAP may receive additional benefit by having CPAP replaced with ASV. Additionally, effective suppression of CSA may improve cardiac function in HF patients.

No abstract

Objective: Continuous positive airway pressure (CPAP) has been established as an effective treatment for obstructive sleep apnea-hypopnea syndrome (OSAHS). Recently, several auto-CPAP devices that can detect upper airway obstructive events and provide information about residual events while patients are on CPAP have come into clinical use. The purpose of this study was to compare the apnea-hypopnea index (AHI) determined by the S8 auto-CPAP device with the AHI derived by polysomnography in patients with OSAHS. Method: Consecutive patients with OSAHS titrated on S8 auto-CPAP were included. The correlation between AHI determined by manual scoring (AHI-PSG) and by S8 (AHI-S8) during an overnight in-hospital polysomnogram with the patient on CPAP was assessed. Furthermore, the apnea index (AI) and the hypopnea index (HI) were evaluated separately. Results: Seventy patients with OSAHS (94% men) were enrolled. The mean AHI on the diagnostic study was 51.9 ± 2.4. During the titration, this device markedly suppressed the respi-ratory events (AHI-PSG, 4.2 ± 0.4; AI, 1.9 ± 0.3; HI, 2.3 ± 0.3). On the other hand, the AHI-S8 was 9.9 ± 0.6 (AI-S8, 2.4 ± 0.3; HI-S8, 7.5 ± 0.4). There was a strong correlation between the overall AHI-PSG and the AHI-S8 (r = 0.85, p < 0.001), with a stronger correlation in the apnea component AI-PSG and the AI-S8 (r = 0.93, p < 0.001), whereas there was a weaker correlation between the HI-PSG and the HI-S8 (r = 0.67, p < 0.001). Conclusions: Using the same airflow signals as those of the CPAP device, a strong correlation between the AHI-PSG and the AHI-S8 was observed. However, the correlation was weakened when the analysis was limited to the HI.

Prolonged P-wave duration, indicating atrial conduction delay, is a marker of left atrial abnormality and is reported as a potent precursor of atrial fibrillation (AF). Several studies have shown that obstructive sleep apnea (OSA) is associated with AF. We evaluated the relationship between OSA and prolonged P-wave duration. Consecutive subjects who underwent overnight polysomnography and showed a normal sinus rhythm, had no history of AF or ischemic heart disease, and showed no evidence of heart failure were enrolled. Apnea-hypopnea index (AHI) is defined as the number of apnea and hypopnea events per hour of sleep. P-wave duration was determined on the basis of the mean duration of three consecutive beats in lead II from a digitally stored electrocardiogram. A total of 250 subjects (middle-aged, predominantly male, mildly obese, with a mean P-wave duration of 106 ms) were enrolled. In addition to age, male gender, body mass index (BMI), hypertension, dyslipidemia, and uric acid and creatinine levels, AHI (r = 0.56; P < 0.001) had significant univariable relationship with P-wave duration. Multivariate regression analysis showed that age, BMI, male gender, and AHI (partial correlation coefficient, 0.47; P < 0.001) were significantly independently correlated to P-wave duration. Severity of OSA is significantly associated with delayed atrial conduction time. Obstructive sleep apnea may lead to progression of atrial remodeling as an AF substrate.

The online-only Data Supplement is available at http://circep.ahajournals.org/lookup/suppl/doi:10.1161/CIRCEP.113.000266/-/DC1. Correspondence to Ken-ichi Maeno, MD, Sleep Center, Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo 105-8470, Japan, E-mail maeken@zk9.so-net.ne.jp Background-Prolonged P-wave duration, indicating atrial conduction delay, is a potent precursor of atrial fibrillation.Obstructive sleep apnea (OSA) is a risk factor for atrial fibrillation development. We investigated the association of P-wave duration with OSA and its treatment. Methods and Results-We enrolled 80 consecutive men with normal sinus rhythms who underwent polysomnography, had no history of atrial fibrillation or ischemic heart disease, and no evidence of heart failure. Signal-averaged P-wave duration (SAPWD) was measured in all participants. Multivariable regression analysis showed that age, hypertension, and log-transformed apnea-hypopnea index were significantly and independently correlated with SAPWD. SAPWD was repeatedly measured after 1 month of continuous positive airway pressure (CPAP) therapy in 62 patients with moderateto-severe OSA. As controls, 18 patients with moderate-to-severe OSA were enrolled. Their SAPWD was also measured at baseline and after 1 month without CPAP therapy. No significant change in SAPWD was found between baseline and after 1 month in the controls. However, SAPWD was significantly shortened after 1 month of CPAP therapy (from 137.5±8.6 to 129.7±8.5 ms; P<0.001), and the SAPWD change was significantly different in patients with CPAP therapy compared with controls (P<0.001). In addition, the SAPWD change in patients with CPAP therapy correlated inversely with nightly CPAP usage (r=−0.52; P<0.001). Conclusions-OSA severity was significantly associated with prolonged SAPWD. CPAP therapy significantly shortened SAPWD in patients with moderate-to-severe OSA. Thus, OSA may cause atrial conduction disturbances, leading to an increased risk of atrial fibrillation development, which may be modifiable by alleviating OSA with CPAP therapy. (Circ Arrhythm Electrophysiol. 2013;6:287-293.)