Low-cost paperless electrocardiograph for low-income countries, with derived V leads and a QRS detection algorithm.

A low-cost device capable of recording a full 12-lead electrocardiogram (ECG) is described using a commercially available analogue front end (ADS1293) and a microprocessor (ESP32) transmitting a signal by Bluetooth to a smartphone. Comparison of the measured V leads and V leads derived by vector analysis using a transverse plane 0° reference vector (lead I) showed significant cross-correlation both for traces acquired from 120 Blantyre patients (0.43) and from the historical PhysioNet ECG database (0.85) and also when a + 30° transverse plane vector (-aVR) was used (0.50 Blantyre, 0.83 PhysioNet). Good correlation was also found between the mean transverse axis vector for the synchronous PhysioNet data (r = 0.91) but not for the asynchronous Blantyre data (r = 0.13) perhaps as a result of the QRS detection algorithm employed.