Electrocardiographic recording in horses at rest: a concordance analysis of two methods

Cardiac arrhythmias are frequently detected during routine auscultation in athletic horses. Assessment of their clinical significance requires electrocardiography (ECG) to analyze waveforms and intervals. In recent years, portable ECG devices have been introduced to simplify electrocardiographic examination, offering advantages such as ease of use and the ability to review results via a smartphone. This study evaluated the utility and accuracy of a portable ECG device compared with a standard electrocardiograph. Simultaneous ECG recordings were obtained from 28 healthy adult horses at rest using a portable device (eKuore) and a standard electrocardiograph (Cardioline Vet600). Agreement between the two methods was assessed using Passing-Bablok regression and Bland-Altman analysis. All recordings were independently interpreted by two observers. A significant bias was observed between methods for heart rate, PR interval, and QRS duration, with higher values obtained using the portable device. Two arrhythmias were identified: second-degree atrioventricular block and atrial fibrillation. Agreement for arrhythmia detection was perfect (κ = 1.00), while agreement for heart rhythm classification (bradycardia, normal rhythm, or tachycardia) was good (κ = 0.73). In conclusion, the portable device demonstrated good diagnostic performance for arrhythmia detection during routine clinical examinations. However, further studies are required to establish reference intervals specific to this device.