Application of a smartphone modulated ECG device for use in equines

Abstract

Introduction Reason for performing the study: This research was performed to determine whether a novel ECG device, that uses smartphone technologies and applications, can be used to obtain electrocardiogram (ECG) readings in horses. Objectives: The main objectives of the present study focused on determining the best method of application for the Alivecor KardiaMobilea (ECGAKM) smartphone modulated electrocardiographic device in horses including body site, skin preparation as well as device orientation. The study also focused on the comparison to the Televet 100 (ECGTV) electrocardiographic device which is commonly employed for ECG recordings in horses. Study design A cross sectional study. Materials and Methods Research was completed in two parts. In the first part, 36 Nooitgedacht pony mares were used to determine the best site of application, method of skin preparation as well as ECGAKM device orientation for reliable ECG tracings. The different body sites for application of the device included the fourth intercostal space of the left thorax, fourth intercostal space of the right thorax and right triceps muscle mass. The automatically calculated heart rate from the device application was compared to that acquired via auscultation. Once the best method of ECGAKM application had been established, 31 Nooitgedacht pony mares were used to compare the device with a standard ECGTV device. ECG tracings were evaluated for agreement between the two devices considering the PQ, RR, QT and QRS intervals as well as the overall rhythm assessment for the ECG devices. Results The ECGAKM device is best applied in the fourth intercostal space on the left hemithorax in a vertical orientation with reference to the ground and with the skin dampened with 70 % alcohol. Using this configuration, the ECGAKM device was able to achieve acquisition of complete decipherable ECG tracings in 91.67 % of readings. Arrhythmias were noted in 3/31 horses and were determined to conform to sinoatrial blockade/arrest in both the ECGAKM and ECGTV tracings. Independent t tests conducted on the mean values for RR; QT and QRS intervals yielded p-values of 0.73; 1 and 0 respectively. As such the mean values determined for RR and QT intervals were not significantly different, however it was determined that the mean values for the QRS interval were significantly different for the two devices. Independent-samples Mann Whitney U test indicated that the distribution of values of mean PQ interval were the same over the ECGAKM and ECGTV categories. These values for PQ, RR, QT, and QRS intervals were then also analysed using Bland-Altman plots. Discussion and Conclusion

The left fourth ICS with a vertical device orientation yielded the best diagnostic quality ECG tracings. There was acceptable agreement between the ECGTV and ECGAKM devices. The ECGAKM device appears to have potential to become entrenched as a basic screening tool with applicability in the field.