Sessions

Electrocardiography (ECG) remains the gold standard for diagnosing cardiac arrhythmias in horses. Although arrhythmias are frequently identified during routine cardiac auscultation, an ECG is required for a definitive diagnosis and to determine their underlying electrical basis. Conventional ECG recording in horses requires multiple electrodes, cables, and specialised equipment. These systems are relatively expensive and can be cumbersome to use in the field; hence, electrocardiography is usually underutilised in ambulatory equine practice. Recent technological advances have introduced significantly cheaper smartphone-based, wearable or hand-held ECG devices for humans. As practical alternatives, some of these have been validated in horses. These systems typically consist of a single-lead recorder connected to a smartphone application, which produces tracings that can be stored and shared digitally.

The aim of our study was to validate a wireless, hand-held human ECG device, called WIWE, in horses. This device was used simultaneously with a reference electrocardiograph (Televet) in 71 animals. The WIWE device records 60-second-long ECGs, which are stored in a mobile phone application. The WIWE ECGs were obtained from the left precordial area, while the reference ECGs were recorded using a base-apex lead. The electrocardiograms obtained by the two devices were compared qualitatively and quantitatively. Qualitative evaluation included manual control of the presence and visibility of P, QRS and T waves, and the recognition of arrhythmias. The durations of the P waves, QRS complexes, PQ, QT, and RR intervals were determined for both methods. The devices could create CSV files, which were then exported to a computer. On the computer, the durations of the waves and intervals were extracted and compared statistically. The WIWE ECGs were of acceptable quality, with a clear presence of the waves. Most of the horses (52 of 71) had sinus rhythm. The remaining 19 animals showed arrhythmias as follows: sinus arrhythmia (4), sinus block (1), second-degree atrioventricular block (11), atrial premature complex (1), and atrial fibrillation (2) on the reference ECGs. These alterations were also well visible on the WIWE traces. The duration of the P wave (mean±SD) for the Televet and WIWE ECGs was 143±14.7 milliseconds (ms) and 131±21.5 ms, respectively. These data for the PQ intervals were 286±3.7 ms and 275±34.3 ms, for the QRS complexes were 105±2.8 ms and 97±10.9 ms, for the QT intervals were 408±26.5 ms and 425±49 ms, and for the RR intervals were 1562±339 and 1300±302 ms, respectively.

In conclusion, we found that the WIWE device is a user-friendly and cheap alternative to a reference electrocardiograph, providing practical and clinically relevant information for initial rhythm analysis in horses in ambulatory practices, which can facilitate referral for further diagnostic workup.