Original articleUsefulness of ambulatory ECG in the diagnosis of sleep-related breathing disorders

Abstract

Background: Sleep-related breathing disorders (SRBD) are the additional factor related to poor prognosis in patients with cardiovascular disorders. The apnoea/hypopnoea index (AHI), describing the number of apnoea and hypopnoea episodes per one hour of sleep, has been used as a marker of severity of the disorder. The disease is present in 4% of men and 2% of women above 40 years of age. However, SRBD are diagnosed in less than 3% of patients with this syndrome due to lack of awareness of the disease among health care practitioners and patients. Polysomnography (PSG) has been used as a golden standard for detecting SRBD, however this test is available only in selected centres. Therefore, a simple, fast and inexpensive test for screening for SRBD is necessary. Respiratory activity influences the amplitude of ECG signal whereas heart rate variability (HRV) depicts the activity of the autonomic nervous system. These associations have been used to develop a new method for detection of SRBD involving analysis of HRV and morphology of ECG signal in ECG monitoring. Aim: Assessment of accuracy of SRBD detection using estimated AHI (Est.AHI), calculated from Holter ECG recordings. Methods: In a study group consisting of 74 patients tested for SRBD, simultaneous PSG and 24-hour ECG monitoring were performed. Following PSG, AHI for each patient was calculated. According to the AHI values patients were classified as SRBD patients (AHI >15), non-SRBD patients (AHIWstęp: Zaburzenia oddychania podczas snu (ZOPS) są czynnikiem obciążającym rokowanie w wielu chorobach układu sercowo-naczyniowego. Wykładnikiem ZOPS jest wskaźnik bezdechów i spłyceń oddychania przypadający na godzinę snu, zwany AHI (ang. apnoe/hypopnoe index). Na ZOPS cierpi ok. 4% mężczyzn i 2% kobiet w wieku >40 lat. Z powodu niskiej świadomości problemu zarówno wśród chorych, jak i lekarzy zdiagnozowanych jest 15) zakwalifikowano 34 chorych. W grupie bez ZOPS (AH