A report in the Archives of Internal Medicine links increasingly severe sleep-related breathing disorders in older men with a greater risk of abnormal heart rhythms (arrhythmias). The report also explains that differing types of breathing problems are associated with different categories of arrhythmia.

Researchers from Case Western Reserve University School of Medicine, Cleveland, studied 2,911 men who underwent polysomnography between 2003 and 2005. 

High numbers of episodes of paused or shallow breathing were associated with increased odds of two types of arrhythmias—one involving the heart’s upper chambers (atria) and one involving the heart’s lower chambers (ventricles). Obstructive sleep apnea (OSA) and lower blood oxygen levels were associated with arrhythmias in the ventricles. Central sleep apnea (CSA) was more strongly associated with arrhythmias in the atria.

More severe cases of sleep-disordered breathing were associated with higher odds of arrhythmia, according to researchers.

“There also seems to be a threshold effect such that moderate-to-severe sleep-disordered breathing confers the greatest increased odds of clinically significant arrhythmias independent of self-reported heart failure and cardiovascular disease,” wrote the authors.

“This line of investigation also identified hypoxia as the possible culprit pathophysiologic characteristic of sleep-disordered breathing that may serve as the trigger of ventricular cardiac arrhythmia development in older men. The strong associations between central sleep apnea and atrial fibrillation [arrhythmia originating in the heart’s upper chambers] suggest that central sleep apnea may be a sensitive marker of underlying abnormalities in autonomic or cardiac dysfunction associated with atrial fibrillation,” the authors conclude. “Further prospective and intervention studies are needed to better determine causality and the impact of aggressive sleep-disordered breathing interventions on cardiac outcomes.”

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