Sleep Apnea and Nocturnal Cardiac Arrhythmia: A Populational Study

Background

The mechanisms associated with the cardiovascular consequences of obstructivesleep apnea include abrupt changes in autonomic tone, which can trigger cardiacarrhythmias. The authors hypothesized that nocturnal cardiac arrhythmia occursmore frequently in patients with obstructive sleep apnea.

Objective

To analyze the relationship between obstructive sleep apnea and abnormal heartrhythm during sleep in a population sample.

Methods

Cross-sectional study with 1,101 volunteers, who form a representative sample ofthe city of São Paulo. The overnight polysomnography was performed using an EMBLA®S7000 digital system during the regular sleep schedule of the individual. Theelectrocardiogram channel was extracted, duplicated, and then analyzed using aHolter (Cardio Smart®) system.

Results

A total of 767 participants (461 men) with a mean age of 42.00 ± 0.53 years, wereincluded in the analysis. At least one type of nocturnal cardiac rhythmdisturbance (atrial/ventricular arrhythmia or beat) was observed in 62.7% of thesample. The occurrence of nocturnal cardiac arrhythmias was more frequent withincreased disease severity. Rhythm disturbance was observed in 53.3% of the samplewithout breathing sleep disorders, whereas 92.3% of patients with severeobstructive sleep apnea showed cardiac arrhythmia. Isolated atrial and ventricularectopy was more frequent in patients with moderate/severe obstructive sleep apneawhen compared to controls (p < 0.001). After controlling for potentialconfounding factors, age, sex and apnea-hypopnea index were associated withnocturnal cardiac arrhythmia.

Conclusion

Nocturnal cardiac arrhythmia occurs more frequently in patients with obstructivesleep apnea and the prevalence increases with disease severity. Age, sex, and theApnea-hypopnea index were predictors of arrhythmia in this sample.