Potential value of electrocardiogram and photoplethysmogram for non-invasive blood pressure estimation during exercise

Blood pressure (BP) monitoring is required to ensure safety of home-based exercise in seniors. Pulse transit time (PTT) defined as the time it takes a pulse wave to travel between two arterial sites is considered to be inversely proportional to BP. Different approaches have been described to calculate PTT using photoplethysmogram (PPG) and electrocardiogram (ECG) however it is not clear which approach produces better BP estimates. The purpose of this study was to compare potential value of different approaches for calculating PTT and other derivatives of PPG and ECG described in the literature for assessing BP during exercise. Three calibration points were collected from five study participants at different levels of exertion on three different days. A high precision automated BP monitor was used to obtain reference BP. A correlation matrix between PPG/ECG derivatives and the reference BP values was analyzed. Based on the bivariate correlation analysis, PPG/ECG derivatives that demonstrated the most prominent association with reference BP were identified. The results of the study confirmed the value of individualized calibration for BP estimation using PTT and identified optimal means to derive it from PPG and ECG.