Vectorcardiography at rest and during exercise in horses using the Delta (Δ) 12-lead configuration

Area of Science:

• Veterinary Cardiology
• Equine Medicine
• Diagnostic Imaging

Background:

• Twelve-lead electrocardiography (ECG) is crucial in human cardiology but lacks standardization in equine medicine.
• Inconsistent findings hinder the diagnostic utility of equine ECG.

Purpose of the Study:

• To describe normal vectorcardiogram (VCG) variations in horses at rest and during exercise.
• To assess the repeatability and observer variations of a Delta 12-lead ECG method for VCG derivation.

Main Methods:

• A prospective, observational study involving 102 healthy Warmblood horses.
• Electrocardiograms were recorded using a Delta 12-lead configuration with precordial electrodes.
• Data analysis involved custom MATLAB scripts and statistical assessment in R for repeatability and observer reliability.

Main Results:

• The Delta 12-lead ECG configuration and derived VCG demonstrated high repeatability.
• Significant intra- and interobserver reliability were observed at rest and during exercise.
• Consistent mean directions of the P wave and QRS complex were found, with specific loop orientations described.

Conclusions:

• The Delta 12-lead configuration and derived VCG provide consistent patterns in horses during sinus rhythm.
• This standardized approach shows promise for enhancing the diagnosis of atrial and ventricular arrhythmias.
• The orthogonal XYZ-leads offer an interpretable format for practicing veterinarians.