Portable sleep monitoring

All patients perform a portable overnight sleep recording using the validated device Embletta Gold (PDS; Medcare, Reykjavik, Iceland) (15). In order to validate the portable sleep monitoring in this population, 100 consecutive patients at the Instituto do Coração performed simultaneous full polysomnography, as previously described (17). The sleep study is scored as previously described (18). Apnea is defined by a ≥90% decrease in the airflow from the baseline value for ≥10 seconds. We further classified apnea in obstructive or central based on the presence or absence, respectively, of respiratory-related chest wall excursions. Hypopnea is defined by a ≥30% decrease in the airflow from the baseline value that lasted ≥10 seconds and occurred in conjunction with ≥3% oxygen desaturation (18). OSA is defined by an AHI ≥15 events / hour, because mild OSA seems to not have significant cardiovascular consequences (19).