Electrocardiographic recordings of foals using a new smartphone-based digital device

Background Smartphone-based electrocardiography (ECG) is increasingly explored as a practical tool for cardiac assessment in veterinary species. Aims The aim of this prospective observational study was to investigate the usability and reliability of a new smartphone-based ECG system (Eko DUO) in healthy foals. Methods A total of 39 foals, aged 1 to 59 days, were enrolled. ECGs were recorded using the smartphone device in all animals, while a subgroup of 10 foals also underwent simultaneous recording with a conventional base-apex ECG (rECG) to enable direct comparison. All tracings were reviewed blindly by a single evaluator to assess interpretability, rhythm, and ECG parameters. Statistical analysis was performed. Results The smartphone ECG (sECG) provided readable tracings in all foals without requiring clipping or sedation. Sinus rhythm was identified in every subject, and heart rate classification (normal, bradycardia, or tachycardia) showed complete concordance with the rECG, supporting its clinical applicability for rapid cardiac assessment. No significant discrepancies were detected for heart rate, PR interval, or QT interval measurements, although P wave duration was shorter and QRS complex slightly longer in sECG recordings. The polarity of QRS complexes matched across systems, while P wave polarity varied. A moderate agreement concerning ECG quality and artifact was found. Conclusion The smartphone ECG system showed good performance in field conditions, enabling rapid acquisition of clinically interpretable tracings and accurate heart rate evaluation, though variations in wave morphology should be acknowledged during clinical use.