Using synchrosqueezing transform to discover breathing dynamics from ECG signals

The acquisition of breathing dynamics without directly recording the respiratory signals is beneficial in many clinical settings. The electrocardiography (ECG)-derived respiration (EDR) algorithm enables data acquisition in this manner. However, the EDR algorithm fails in analyzing such data for patients with atrial fibrillation (AF) because of their highly irregular heart rates. To resolve these problems, we introduce a new algorithm, referred to as SSTEDR, to extract the breathing dynamics directly from the single lead ECG signal; it is based on the EDR algorithm and the time–frequency representation technique referred to as the synchrosqueezing transform. We report a preliminary result about the relationship between the anesthetic depth and breathing dynamics. To the best of our knowledge, this is the first algorithm allowing us to extract the breathing dynamics of patients with obvious AF from the single lead ECG signal.