Multiple Catheter Recording in Horses to Investigate Atrial Depolarization Pattern During Sinus Rhythm and Induced Premature Atrial Complexes.
Abstract: Detailed characterization of arrhythmias can be performed by multiple catheter mapping; but this has not yet been explored in horses. Objective: Perform ultrasound-guided multiple catheter mapping of the right heart during sinus rhythm and right and left atrial pacing to identify activation patterns characteristic of the origin of ectopy. Obtain His signals and effective refractory periods (ERP). Methods: Eight healthy adult horses. Methods: Experimental study. Recording catheters were placed at the terminal crest, intervenous tubercle, caudal vena cava, and coronary sinus. Right atrial pacing was performed in standing, sedated horses from each catheter and from the cranial vena cava, right atrial appendage, and right atrial free wall. Left atrial pacing was performed during general anesthesia at the four pulmonary vein ostia, left atrial appendage, and interatrial septum. Atrial activation patterns were recorded from the catheters during sinus rhythm and during pacing at the different sites. During sinus rhythm, the His bundle was recorded, and ERP at different sites was determined. Results: Characteristic activation maps during sinus rhythm and pacing were identified. Late coronary sinus activation indicated ectopy originating from the right atrium or ostium III. The direction of coronary sinus electrode activation aided in differentiating left atrial ectopy locations. His signals were recorded in 5/8 horses. Atrial ERP varied between 170 and 420 ms with inter-horse and intra-horse variation. Conclusions: Performing an electrophysiological study in horses, including multiple catheter recording, was feasible. Pacing-induced ectopy resulted in characteristic activation patterns, which might aid in identifying the site of atrial ectopy.
© 2025 The Author(s). Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.
Publication Date: 2025-09-18 PubMed ID: 40966305PubMed Central: PMC12445429DOI: 10.1111/jvim.70218Google Scholar: Lookup
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Summary
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Research Overview
- This study developed and tested a technique using multiple catheter electrophysiological mapping in horses to characterize atrial electrical activation during normal heart rhythm and induced abnormal beats.
- The goal was to identify patterns of atrial activation that could pinpoint the origin of abnormal electrical impulses (ectopy) within the atria.
Background and Purpose
- Atrial arrhythmias in horses can be challenging to diagnose due to limited detailed mapping techniques available compared to human cardiology.
- Multiple catheter mapping allows simultaneous recording from different intracardiac sites to provide detailed electrical activation maps.
- This study aimed to apply this advanced mapping method to the right heart of horses and to perform pacing from various atrial locations to observe characteristic electrical activation sequences.
- Additional objectives included recording electrical signals from the His bundle (part of the heart’s electrical conduction system) and determining effective refractory periods (ERP), which are measures of electrical recovery times in heart tissue.
Methods
- Eight healthy adult horses were included in this experimental study.
- Multiple electrophysiological catheters were placed in the heart at specific anatomic landmarks in the right atrium: terminal crest, intervenous tubercle, caudal vena cava, and the coronary sinus. Ultrasound guidance was used to place these catheters accurately.
- Right atrial pacing (electrical stimulation) was performed in sedated horses standing up, from each of these catheter sites as well as from the cranial vena cava, right atrial appendage, and right atrial free wall.
- Left atrial pacing was done under general anesthesia at four pulmonary vein ostia, the left atrial appendage, and the interatrial septum.
- Atrial activation patterns were recorded from the catheters during both natural sinus rhythm and during the pacing protocols.
- The His bundle signal was recorded during sinus rhythm whenever possible, and ERP was measured at different sites to assess electrical recovery properties.
Results
- Distinct activation maps were identified both during normal rhythm and various pacing points, revealing characteristic sequences that corresponded to specific atrial locations.
- Late activation in the coronary sinus suggested that ectopic beats originated from the right atrium or from an anatomical area called ostium III.
- The directional pattern of activation recorded by coronary sinus electrodes helped differentiate whether ectopy originated from the left atrium and its sublocations.
- The His bundle electrical signals were successfully recorded in 5 out of 8 horses, demonstrating feasibility in this species.
- Atrial effective refractory periods varied widely (170 to 420 ms), showing variability both between horses and between different atrial regions within the same horse.
Conclusions and Significance
- This study demonstrated that it is feasible to perform detailed electrophysiological studies in horses using multiple intracardiac catheters.
- The methodology allowed the identification of distinctive electrical activation patterns during sinus rhythm and paced ectopic beats.
- Such activation maps can potentially aid clinicians and researchers in identifying the site of origin of atrial ectopy in horses, which is important for diagnosis and treatment of atrial arrhythmias.
- Recording His bundle signals and measuring ERP adds valuable information about the electrical conduction properties in equine hearts.
- Overall, the findings provide a framework for further investigations into the mechanisms of atrial arrhythmias and potentially improved therapeutic interventions in equine cardiology.
Cite This Article
APA
Buschmann E, Van Steenkiste G, Vernemmen I, Demeyere M, Schauvliege S, Decloedt A, van Loon G.
(2025).
Multiple Catheter Recording in Horses to Investigate Atrial Depolarization Pattern During Sinus Rhythm and Induced Premature Atrial Complexes.
J Vet Intern Med, 39(5), e70218.
https://doi.org/10.1111/jvim.70218 Publication
Researcher Affiliations
- Equine Cardioteam Ghent, Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
- Equine Cardioteam Ghent, Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
- Equine Cardioteam Ghent, Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
- Equine Cardioteam Ghent, Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
- Department of Large Animal Surgery, Anaesthesia and Orthopaedics, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
- Equine Cardioteam Ghent, Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
- Equine Cardioteam Ghent, Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
MeSH Terms
- Animals
- Horses
- Male
- Female
- Atrial Premature Complexes / veterinary
- Atrial Premature Complexes / physiopathology
- Atrial Premature Complexes / diagnosis
- Horse Diseases / diagnosis
- Horse Diseases / physiopathology
- Heart Atria / physiopathology
- Cardiac Catheterization / veterinary
Grant Funding
- 01B05818 / Bijzonder Onderzoeksfonds UGent
- 1S71521N / Fonds Wetenschappelijk Onderzoek
- 1SA2223N / Fonds Wetenschappelijk Onderzoek
- 1SE9122N / Fonds Wetenschappelijk Onderzoek
Conflict of Interest Statement
Authors declare no off‐label use of antimicrobials. The authors declare no conflicts of interest.
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