[Comparison of different electrocardiographic techniques for the detection of arrhythmias in horses].

The research article compares the usefulness of different electrocardiographic techniques–resting-ECG, exercise-ECG, and Holter-ECG–in detecting heart arrhythmias in horses. The findings suggest that the Holter-ECG is the most useful technique overall, offering additional diagnostic information that the other two don’t provide.

Research Methodology

• The study was carried out on two groups of horses, one consisting of 20 healthy horses showing no signs of cardiac issues and the other, 80 horses that showed abnormal findings like valvular regurgitation and/or atrial fibrillation.
• Each horse underwent three types of electrocardiographic examinations: resting-ECG for 1 minute, exercise-ECG, and Holter-ECG.

Results and Comparison

• Compared to the resting-ECG, the exercise-ECG showed more atrial and ventricular premature beats in the horses. This means that exercise-ECG was more able to pick up early beats in horses, something resting-ECG was less efficient at.
• The study found that the Holter-ECG had a higher detection rate of 2nd degree atrioventricular or sinuatrial blocks and premature ventricular and atrial depolarisations compared to both other methods.
• In comparison with the exercise-ECG, the Holter-ECG registered more instances of 2nd degree atrioventricular blocks and premature contractions.
• All ECG types detected atrial fibrillation, an irregular and often rapid heart rate. However, the Holter-ECG provided additional information. For example, it found that three of 16 horses with atrial fibrillation had R-on-T-episodes (a potentially dangerous irregularity) during monitoring.

Key Findings and Conclusions

• The variety of additional findings made by Holter-ECG emphasizes its value. It detected a 2nd degree atrioventricular block associated with an adjacent ventricular escape beat in a horse that had not shown any clinical or echocardiographic issues.
• Moreover, an accelerated idioventricular rhythm was identified in two horses, one of which had previously undiagnosed mitral valve insufficiency.
• These findings suggest that the Holter-ECG is particularly useful in the evaluation of heart disease in horses and can contribute additional diagnostic information not obtainable from the other two electrocardiographic procedures.
• However, the study also points out that Holter-ECG should not replace the exercise-ECG but can be used as a supplementary diagnostic tool for more comprehensive results.