AUTHOR=Penzel Thomas , Kantelhardt Jan W. , Bartsch Ronny P. , Riedl Maik , Kraemer Jan F. , Wessel Niels , Garcia Carmen , Glos Martin , Fietze Ingo , Schöbel Christoph TITLE=Modulations of Heart Rate, ECG, and Cardio-Respiratory Coupling Observed in Polysomnography JOURNAL=Frontiers in Physiology VOLUME=7 YEAR=2016 URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2016.00460 DOI=10.3389/fphys.2016.00460 ISSN=1664-042X ABSTRACT=

The cardiac component of cardio-respiratory polysomnography is covered by ECG and heart rate recordings. However, their evaluation is often underrepresented in summarizing reports. As complements to EEG, EOG, and EMG, these signals provide diagnostic information for autonomic nervous activity during sleep. This review presents major methodological developments in sleep research regarding heart rate, ECG, and cardio-respiratory couplings in a chronological (historical) sequence. It presents physiological and pathophysiological insights related to sleep medicine obtained by new technical developments. Recorded nocturnal ECG facilitates conventional heart rate variability (HRV) analysis, studies of cyclical variations of heart rate, and analysis of ECG waveform. In healthy adults, the autonomous nervous system is regulated in totally different ways during wakefulness, slow-wave sleep, and REM sleep. Analysis of beat-to-beat heart-rate variations with statistical methods enables us to estimate sleep stages based on the differences in autonomic nervous system regulation. Furthermore, up to some degree, it is possible to track transitions from wakefulness to sleep by analysis of heart-rate variations. ECG and heart rate analysis allow assessment of selected sleep disorders as well. Sleep disordered breathing can be detected reliably by studying cyclical variation of heart rate combined with respiration-modulated changes in ECG morphology (amplitude of R wave and T wave).