All work on this project was performed at the Ontario Veterinary College. This study has been presented in part as an abstract at the ACVIM forum in Charlotte, NC, in June 2003 and at the Cardiostim 2004 conference in Nice, France in June 2004.
Transvenous Electrical Cardioversion of Equine Atrial Fibrillation: Patient Factors and Clinical Results in 72 Treatment Episodes
Article first published online: 10 JUL 2008
Copyright © 2008 by the American College of Veterinary Internal Medicine
Journal of Veterinary Internal Medicine
Volume 22, Issue 3, pages 609–615, May–June 2008
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How to Cite
McGurrin, M.K.J., Physick-Sheard, P.W. and Kenney, D.G. (2008), Transvenous Electrical Cardioversion of Equine Atrial Fibrillation: Patient Factors and Clinical Results in 72 Treatment Episodes. Journal of Veterinary Internal Medicine, 22: 609–615. doi: 10.1111/j.1939-1676.2008.0081.x
- Issue published online: 10 JUL 2008
- Article first published online: 10 JUL 2008
- Submitted January 30, 2007; Revised May 6, 2007; Accepted November 12, 2007.
- Cardiac disease;
Background: Transvenous electrical cardioversion (TVEC) has been developed for treatment of atrial fibrillation (AF) in horses. The relationship among patient variables, treatment response, and outcome in a typical referral population has not been evaluated.
Hypothesis: Patient variables such as age, sex, weight, and duration of arrhythmia affect prognosis for response to treatment and the energy level at which cardioversion occurs.
Animals: TVEC was applied to 72 episodes of lone AF in 63 client-owned performance horses, with the majority (54) being Standardbred racehorses.
Methods: Catheterization of the right atrium (RA) and pulmonary artery (PA) through the jugular vein was used for electrode placement before horses were placed under general anesthesia. Biphasic, truncated exponential shock waves were delivered at incremental energy levels until cardioversion was achieved or a maximum single-energy level of 300 J was reached (cumulative energy 50–1,960 J). A multivariate model was constructed to evaluate influence of patient factors on cardioversion energy.
Results: Cardioversion was achieved in 71 of 72 episodes (62 of 63 horses) at a mean energy of 165.43 ± 8.75 J. Cardioversion energy was higher for females than for males, and for interaction terms, weight was negatively related to energy in females and positively related in males. Age was positively related to cardioversion energy in females. No relationship was identified between duration of arrhythmia before treatment and prognosis for response or cardioversion energy.
Conclusions and Clinical Importance: TVEC is highly effective in the treatment of lone AF in horses. Although age and sex influence cardioversion energy level, duration of arrhythmia does not.