A Novel Approach to Simultaneous Phonocardiography and Electrocardiography During Auscultation

Abstract

The combination of the phonocardiogram (PCG) and the electrocardiogram (ECG) allows the simultaneous evaluation of the heart’s mechanical and electrical conditions and could significantly improve the accuracy of an initial cardiovascular disease diagnosis. Both signals can be acquired using non-invasive and low-complexity devices. However, the currently available devices do not have a suitable form factor for the established medical routines, restricting their usability in clinical practice. They are also bound to proprietary tools that limit collaboration, which are constraints for both clinicians and researchers. To tackle these problems, we propose a novel electronic stethoscope that combines PCG and ECG sensors which use polymer-based dry electrodes with a previously validated 3D-printed acoustic stethoscope. We performed an experimental evaluation of the sensors, and the temporal relation between the two signals and heartbeat morphology were assessed. The effect of the rotation of the stethoscope head at different angles was also studied, further extending the state-of-the-art in the field. It was verified that the ECG lead voltages at different angles follow Kirchhoff’s law, similar to the Einthoven leads. By comparing the ECG waveforms between a reference and the experimental device, the best case reached a Pearson’s correlation coefficient of 0.916±0.008. The results demonstrate the validity of the proposed electronic stethoscope, establishing a foundation for further development. The accessibility, low cost, and simplicity of the device should significantly facilitate its integration into healthcare facilities and telemedicine interventions, as well as into research and education.

Keywords

• Auscultation
• electrocardiogram
• electronic stethoscope
• multimodal signals
• phonocardiogram