[Effect of age on electrocardiogram entropy value of parameters by sleep respiratory disturbance].

Spectral entropy of electrocardiogram (ECG), which was calculated using the MemCalc method with a portable bio-signal measurement instrument (PBSM), might be a possible parameter for evaluating the quality of sleep. This study assessed the effects of ECG spectral entropy on obstructive sleep apnea/hypopnea syndrome (OSAHS) depending on age. ECG was recorded using a PBSM, and the maximum entropy of ECG every 9 RR intervals was calculated. These entropies were compared with the age and sleeping indices obtained with a conventional polysomnography (PSG) system. Seventy-six patients suspected of OSAHS were recorded from 20:00 to 06:00 using a conventional PSG system (Alice III) and a PBSM (MemCalc-Makin2) simultaneously. ECG entropy showed correlations to high frequency (HF, 0.15-0.40 Hz) heart rate variability in the cardiac parasympathetic activity index, as did the ECG entropy value, and a negative correlation was found with the age (r = 0.538, p < 0.0001), and positive correlation with the HF value (r = 0.810, p < 0.0001). The ECG entropy value in subjects aged > or = 40 with no different sleep respiratory disturbance index by PSG data (AHI, Arousal Index, DSI, and sleep efficiency, etc.) to 60 years old was compared with those aged > or = 60. The ECG entropy value and HF value decreased at > or = 60 years old with statistically significant. The value of ECG entropy corresponds to cardiac parasympathetic function, and it decreases according to age (increase by the absolute value).