Cardiac arrhythmia detection using photoplethysmography

Cardiovascular Diseases (CVDs) cause a very large number of casualties around the world every year and cardiac arrhythmias contribute to significant proportion of CVD related deaths. Bedside cardiac activity monitors in hospitals are based on electrocardiogram (ECG) processing and are known to produce too many false alarms. Moving beyond bedside care, ECG is not very suitable for use in wearable devices. Photoplethysmography (PPG) on the other hand provides an inexpensive and more wearable device-friendly alternative. This work presents a technique to detect life threatening arrhythmias using only PPG waveforms. PhysioNet Challenge 2015 data is used to detect five types of arrhythmias namely, tachycardia, bradycardia, asystole, ventricular tachycardia and ventricular fibrillation. A novel technique is employed to assign pulse quality index to every PPG pulse and highest quality portion of the signal is used for detection. Results indicate that PPG provides a viable alternative for conventional ECG based detection. An overall true positive rate (TPR) of 93% was achieved with true negative rate (TNR) of 53.78% suggesting that PPG is a viable option for arrhythmia detection.