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

Overview

• This study evaluated the usability and reliability of a new smartphone-based electrocardiogram (ECG) device (Eko DUO) for recording cardiac activity in healthy foals.
• The results showed that the smartphone ECG produced clinically interpretable tracings comparable to conventional ECG methods, supporting its use for rapid cardiac assessment in foals.

Introduction and Purpose

• Smartphone-based ECG technology is increasingly being investigated as a convenient, portable option for cardiac monitoring in animals.
• The primary goal was to test whether the Eko DUO smartphone ECG could reliably record heart rhythms and parameters in young foals aged 1 to 59 days.
• Specifically, the study aimed to assess the device’s usability in the field without sedation or shaving and to compare its accuracy against standard base-apex ECG recordings.

Methods

• A total of 39 healthy foals were included in this prospective observational study.
• ECGs were recorded on all foals using the new smartphone device.
• A subgroup of 10 foals underwent simultaneous ECG recordings with both the smartphone device and a conventional base-apex ECG (rECG) for direct comparison.
• All recorded ECG traces were reviewed blindly by one evaluator to reduce bias.
• The evaluation criteria included the interpretability of tracings, heart rhythm identification, and measurement of ECG parameters such as heart rate, PR interval, QT interval, P wave duration, and QRS complex duration.
• Statistical analyses were conducted to compare measurements between the smartphone ECG and the reference conventional ECG.

Results

• The smartphone ECG device generated readable and interpretable ECG tracings in all 39 foals without needing clipping of fur or sedation, which is advantageous for field conditions.
• Sinus rhythm – a normal heart rhythm – was correctly identified in every foal, demonstrating the device’s capability for rhythm analysis.
• Heart rate classifications (normal, bradycardia, tachycardia) were in complete agreement between the smartphone ECG and the conventional ECG, indicating reliable heart rate measurement.
• There were no significant differences in key ECG time intervals such as heart rate, PR interval, or QT interval when comparing the two devices.
• Differences noted included:
  • The P wave duration recorded by the smartphone device was shorter than the conventional ECG’s P wave duration.
  • The QRS complex duration on the smartphone ECG was slightly longer.
• Polarity analysis:
  • The polarity of the QRS complexes (which represent ventricular depolarization) matched between devices.
  • P wave polarity (atrial depolarization) showed variation between the two devices.
• Quality and artifact levels showed moderate agreement, indicating some variability in signal quality but still generally acceptable traces.

Conclusions and Clinical Implications

• The Eko DUO smartphone ECG system performs well when used in healthy foals under typical field conditions.
• It allows for the rapid acquisition of clinically useful ECG tracings without extensive preparation like clipping or sedation, enhancing practical usability.
• The device accurately evaluates heart rate and detects rhythm abnormalities, making it suitable for quick cardiac assessments.
• However, some differences in wave morphology—such as P wave duration and polarity—should be taken into account during interpretation to avoid misdiagnosis.
• Overall, the smartphone-based ECG is a promising tool for veterinary practice, offering a balance of convenience and sufficient diagnostic reliability in foals.