Peer-reviewed veterinary case report
Sustained atrial tachycardia in horses and treatment by transvenous electrical cardioversion.
- Journal:
- Equine veterinary journal
- Year:
- 2019
- Authors:
- Van Steenkiste, G et al.
- Affiliation:
- Department of Large Animal Internal Medicine
- Species:
- horse
Plain-English summary
This study looked at seven horses diagnosed with a heart condition called sustained atrial tachycardia, which means their hearts were beating too fast. They were treated with a procedure called transvenous electrical cardioversion (TVEC), which helps restore a normal heart rhythm. All seven horses successfully returned to a normal heart rhythm right after the treatment, and five of them maintained this normal rhythm for up to five years. However, one horse developed a different heart issue the day after treatment, and another had a recurrence eight years later. Overall, the treatment was very effective, but there were some cases of recurrence that pet owners should be aware of.
Abstract
BACKGROUND: Atrial tachycardia including focal atrial tachycardia and macroreentrant atrial tachycardia (atrial flutter), are occasionally found in horses. Diagnosis, treatment and follow-up of these arrhythmias has been inadequately described. OBJECTIVES: To describe the findings on surface electrocardiography (ECG), intra-atrial electrogram recording and tissue Doppler imaging (TDI), the response to treatment by transvenous electrical cardioversion (TVEC), and TDI follow-up, of sustained atrial tachycardia in horses. STUDY DESIGN: Case series. METHODS: Records from horses with sustained atrial tachycardia treated by biphasic TVEC at Ghent University were reviewed. Horses with atrial fibrillation were not included. RESULTS: Seven horses with sustained atrial tachycardia were treated with TVEC. In six cases an exercise ECG was available and in 4 a 12-lead ECG had been recorded. The mean bias between atrial cycle length measured from a right atrial intra-atrial electrogram and from TDI ranged between -2 and 3 ms depending on the sampled region. All seven cases converted to sinus rhythm during the first TVEC procedure. TDI showed atrial contractile function recovery similar to cases that were treated for atrial fibrillation. One case developed atrial fibrillation 1 day after TVEC treatment, another case showed recurrence 8 years post conversion. The other five cases were still in sinus rhythm at 9 months - 5 years after TVEC. MAIN LIMITATIONS: Due to the small number of patients, data on recurrence and follow-up of atrial recovery should be interpreted with caution. Since no invasive electrophysiology studies were performed, differentiation between focal atrial tachycardia and atrial flutter remains speculative. CONCLUSIONS: Treatment of focal atrial tachycardia or atrial flutter by TVEC has a very high success rate. Tissue Doppler imaging allows noninvasive measurement of atrial cycle length and suggests reduced atrial function after cardioversion. Long-term prognosis after cardioversion seemed similar compared to horses with atrial fibrillation, although early recurrence (<24 h) occurred in one horse.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/30648752/