Background-Despite the adverse cardiovascular consequences of obstructive sleep apnea, the majority of patients remain undiagnosed. To explore an efficient ECG-based screening tool for obstructive sleep apnea, we examined the usefulness of automated detection of cyclic variation of heart rate (CVHR) in a large-scale controlled clinical setting. Methods and Results-We developed an algorithm of autocorrelated wave detection with adaptive threshold (ACAT). The algorithm was optimized with 63 sleep studies in a training cohort, and its performance was confirmed with 70 sleep studies of the Physionet Apnea-ECG database. We then applied the algorithm to ECGs extracted from all-night polysomnograms in 862 consecutive subjects referred for diagnostic sleep study. The number of CVHR per hour (the CVHR index) closely correlated (rϭ0.84) with the apnea-hypopnea index, although the absolute agreement with the apnea-hypopnea index was modest (the upper and lower limits of agreement, 21 per hour and Ϫ19 per hour) with periodic leg movement causing most of the disagreement (PϽ0.001). The CVHR index showed a good performance in identifying the patients with an apnea-hypopnea index Ն15 per hour (area under the receiver-operating characteristic curve, 0.913; 83% sensitivity and 88% specificity, with the predetermined cutoff threshold of CVHR index Ն15 per hour). The classification performance was unaffected by older age (Ն65 years) or cardiac autonomic dysfunction (SD of normal-to-normal R-R intervals over the entire length of recording Ͻ65 ms; area under the receiver-operating characteristic curve, 0.915 and 0.911, respectively). Conclusions-The automated detection of CVHR with the ACAT algorithm provides a powerful ECG-based screening tool for moderate-to-severe obstructive sleep apnea, even in older subjects and in those with cardiac autonomic dysfunction. (Circ Arrhythm Electrophysiol. 2011;4:64-72.)
P Pn ne eu um mo on ni it ti is s d du ur ri in ng g i in nt te er rf fe er ro on n a an nd d/ /o or r h he er rb ba al l d dr ru ug g t th he er ra ap py y i in n p pa at ti ie en nt ts s w wi it th h c ch hr ro on ni ic c a ac ct ti iv ve e h he ep pa at ti it ti is s ABSTRACT: We report four cases of acute pneumonitis due either to interferon, or a herbal drug, " "Sho-saiko-to" ", or both in combination, in patients with chronic active hepatitis, focusing on its pathogenesis and response to prednisolone therapy. These cases shared common clinical features: fever, dry cough, dyspnoea, hypoxaemia, diffuse infiltrates both on chest radiography and chest computed tomography, restrictive pulmonary functional impairment, and alveolitis on examination of transbronchial lung biopsy, all of which suggest acute interstitial pneumonia. Furthermore, lymphocytosis was observed in association with the dominant CD8+ T-cell subset in bronchoalveolar lavage fluid. A lymphocyte stimulation test using peripheral blood was positive to interferon in one case and to Sho-saiko-to in another. All patients responded to oral prednisolone therapy. Peripheral soluble interleukin-2 receptor levels decreased in parallel with improvement in the clinical course. All patients were free of symptoms with a follow-up of 1-3 yrs.We conclude that interferon-and/or Sho-saiko-to-induced acute pneumonitis may be due to allergic-immunological mechanisms rather than toxicity, and that peripheral levels of soluble interleukin-2 receptor appear to be good markers of disease activity.
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