Oesophageal electrocardiography in healthy horses.

The research article is about the successful application of oesophageal electrocardiography (ECG), a technique commonly used in human medicine, in horses, yielding larger P waves compared to other methods.

Research Background

• The research seeks to explore the potential of oesophageal electrocardiography (ECG) in veterinary science, specifically in horses.
• ECG, a well-established method in human medicine, involves measuring the electrical activity of the heart to understand how it is functioning. This technique is particularly useful for magnifying P waves — the first small wave that represents electrical depolarization of the atria.

Research Methods

• The study deployed both bipolar and unipolar ECG, using oesophageal and surface electrodes.
• Oesophageal ECG was carried out in six different recording setups at varying oesophageal depths.
• To determine wave amplitudes, P, Q, R, S, and T waves were measured from three different cardiac cycles for each recording setup and depth.

Research Results

• The research found that oesophageal ECG could be successfully performed on all horses in the study.
• Among all oesophageal recording setups, the largest P waves were recorded at a depth equal to the ‘height of the withers + 10 cm’ (HW(+10)).
• The ratio between the P wave and QRS complex magnitudes (P/QRS(magn)) was largest for intra-oesophageal recordings with an inter-electrode distance of 10 cm, at HW(+10). This ratio was significantly larger than those from base-apex and unipolar recordings.
• Base-apex recording yielded significantly smaller P waves and P/QRS(magn) ratios than all other recording setups, except one combined oesophageal-surface recording (E/S(low)).

Research Conclusion

• Oesophageal ECG recordings were determined to be practical in horses and productive in magnifying the P wave amplitude.
• The procedure shows promise for diagnosing supraventricular tachydysrhythmias (arrhythmias that originate in the atria), and could be used for electrophysiological studies and cardiac pacing.