Extranodal pacemaker activity during sleep - A case study of wireless ECG sensor data

Sleep apnea is a breathing disorder during sleep which is characterized by breathing cessation lasting at least 10 seconds. Sleep apnea is associated with sudden cardiac death. Every apnea event is accompanied by cardiovascular changes. In polysomnography, to perform cardiorespiratory sleep study in today´s sleep laboratories, many parameters such as ECG (electrocardiogram), EEG (electroencephalogram), respiration effort, oronasal airflow, snoring (by microphone) and oxygen saturation in blood are recorded. We present a case where only single channel ECG obtained from wireless electrodes was used to study heart-rate dynamics during sleep apnea events. A sudden change of morphology of atrial P wave in ECG recording was observed during sleep. This observation supports the hypothesis that sinus node is not the only physiological pacemaking structure in the atrium.