A novel approach for obtaining 12‐lead electrocardiograms in horses

Abstract

Background: In equine medicine, 12-lead electrocardiograms (ECGs) rarely are used, which may in part be a result of shortcomings in the existing guidelines for obtaining 12-lead ECGs in horses. The guidelines recommend placing the limb leads on the extremities, which is inappropriate because the ventricular mean electrical axis is then perpendicular to the limb leads, leading to large variations in ECG configuration even among healthy horses. From an electrophysiological point of view, the leads instead should be parallel to the electrical axis to minimize variability. Objective: Develop an improved method for obtaining 12-lead ECGs in horses based on electrophysiology and cardiac electrical vectors relevant to horses. Animals: Thirty-five healthy Standardbred horses. Methods: Two ECGs obtained at rest; 1 ECG with the electrodes placed according to the method developed in the present study, the Copenhagen method, and 1 ECG following existing guidelines. Results: In the Copenhagen method, we repositioned the limb electrodes to the thorax to better capture the electrical activity of the heart. Variation in the mean electrical axis decreased dramatically with the Copenhagen method (SD decreased from 24.6 to 1.6 , P < .001). Consequently, this new method provided stable ECGs with repeatable configurations. Conclusions and Clinical Importance: With this novel method, the ECG is recorded with respect to the electric axis to fully realize the potential of 12-lead ECG in horses. The Copenhagen method delivered more consistent and reliable ECG recordings compared to existing guidelines. The Copenhagen method potentially allows for expanded use of 12-lead ECGs in equine medicine.

Application of an electrocardiography device (iECG) for heart rhythm analysis after exercise in Thoroughbred horses

“…19,20 A recent study found P wave amplitude of iECG recordings was increased when obtained from the right hemithorax. 21 The placement of the iECG device in our study, in an approximately dorsoventral orientation, rotated 30 cranially as previously described 20 was intended to be parallel to the mean electrical axis of the heart, 31 thus maximising the amplitude of QRS complexes. Other studies have described placement in a dorsoventral rotated 60 to 70 craniocaudal, 19 or craniodorsalcaudoventral orientation, 21,23 or in a horizontal, vertical or oblique orientation.…”

An Exploratory Study on Vectorcardiographic Identification of the Site of Origin of Focally Induced Premature Depolarizations in Horses, Part II: The Ventricles

“…This study was approved by the ethical committee of the Faculty of Veterinary Medicine, Ghent University (Merelbeke, Belgium) (EC 2016/35) and animal care was according to their guidelines. Seven warmblood geldings aged 12.5 (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) years (median (range)) with height 163 cm (155-179 cm) at the withers and mass 548 kg (420-706 kg) were used. Four horses were owned by the Faculty of Veterinary Medicine, whereas three horses were donated for scientific research followed by euthanasia because of orthopedic problems.…”

How to record a good quality ECG in horses

“…The arrows show the mean electrical axes (MEAs) (sagittal plane) of the QRS (red arrow) and P wave (green arrow). The MEAs also have a right to left direction in the cardiac frontal plane (Holmes and Alps 1967, Muylle and Oyaert 1971, da Costa and others 2017, Hesselkilde and others 2021). LA Left arm electrode…”