PURPOSE:Individuals with sleep-disordered breathing (SDB) may be at heightened risk of sudden nocturnal cardiac death possibly due to malignant nocturnal arrhythmias. Only limited data have assessed this mechanism in large populations unselected for sleep apnea across a wide range of SDB. We hypothesize that SDB, as measured by the respiratory disturbance index (RDI) and overnight hypoxia, is associated with nocturnal atrial and ventricular arrhythmias.
METHODS:The analytic sample was 2911 men from the Outcomes of Sleep Disorders in Older Men (MrOS) Sleep Study who underwent unattended polysomnography. Indices of SDB were categorized: RDI quartiles (Q1: <5.9, Q2: 5.9-<12.6, Q3: 12.6- <23.9, Q4: >=23.9) and nocturnal hypoxia defined as % sleep time <90% SaO2 (<1, 1–3.5, 3.5–10, >10). The central apnea index (events/hour) was considered as a log transformed continuous variable per 1 unit increase. Arrhythmias during polysomnography considered include atrial fibrillation (AF) and complex ventricular ectopy (CVE), the latter a composite of bigeminy, trigeminy, quadrigeminy or nonsustained ventricular tachycardia. Logistic regression analyses were performed adjusted for age, race, Body Mass Index (BMI), study site, hypertension, diabetes mellitus, pacemaker placement and cardiovascular disease. Odds ratios and 95% confidence intervals are presented.
RESULTS:Subjects were: age 76.4 ± 5.5 (mean+/-SD) years, 91% Caucasian, BMI: 27.2 ± 3.8 kg/m2. In adjusted models, increasing RDI quartile was associated with a progressive increased odds of AF (Q2: 1.17, 0.66–2.07; Q3: 1.45, 0.83–2.53; Q4: 2.07, 1.21–3.53; p-trend 0.004) and CVE (Q2: 1.05, 0.83–1.31; Q3: 1.29, 1.03–1.62; Q4: 1.44, 1.14–1.82; p-trend 0.0006). Level of hypoxia also was associated with CVE (Q2: 1.27, 1.05–1.54; Q3: 1.23, 0.96–1.60; Q4: 1.65, 1.27–2.15; p-trend 0.0003). Central apnea was significantly associated with AF: (1.71, 1.41–2.07) and CVE: (1.14, 1.02–1.27).
CONCLUSION:In this large cohort of older men, increasing RDI was associated with a progressive increase in odds of AF and CVE.
CLINICAL IMPLICATIONS:An increased odds of AF was observed even at a low RDI (> 5.9), suggesting that increased risk may occur at even low levels of SDB.
DISCLOSURE:Reena Mehra, No Financial Disclosure Information; No Product/Research Disclosure Information