Twenty-four hour continuous transvenous temporary right ventricular pacing in healthy horses.
Authors: Avison Amanda, Gelzer Anna R, Reef Virginia B, Wulster Bills Kathryn B, de Solis Cris Navas, Kraus Marc S, Slack JoAnn, Stefanovski Darko, Deacon Lindsay J, Underwood Claire
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: Transvenous Temporary Cardiac Pacing in Horses Transvenous temporary pacing offers a potentially life-saving intervention for horses presenting with symptomatic bradyarrhythmias, yet clinical experience remains limited and largely confined to short-term applications. Researchers at an institutional teaching facility investigated whether a bipolar torque-directed pacing catheter could successfully maintain right ventricular pacing for 24 hours in six healthy adult horses, comparing echocardiographic and fluoroscopic guidance for lead placement and monitoring capture thresholds and pacing failure every six hours throughout the pacing period. Both imaging modalities proved effective for achieving and maintaining lead placement without complications, though lead position significantly influenced success rates: horses with catheters positioned in the right ventricular apex angled caudally experienced no pacing failure and maintained lower capture thresholds, whilst the remaining four horses experienced variable loss of capture (defined as cessation of capture exceeding 20 seconds). These findings establish that medium-term transvenous pacing is technically feasible in awake, unrestricted horses and suggest that optimal right ventricular apex positioning—achievable with either imaging guidance—may substantially reduce the capture threshold variability that currently limits clinical application. For practitioners managing acute bradyarrhythmic emergencies, this work supports the potential utility of temporary pacing as a stabilisation tool, though continuous telemetric ECG monitoring remains essential to detect capture loss and inform clinical decision-making during the critical stabilisation period.
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Practical Takeaways
- •Transvenous temporary pacing is a viable emergency stabilization option for horses with symptomatic bradyarrhythmias; careful lead positioning at the RV apex is critical for success
- •Continuous telemetric ECG monitoring is essential during pacing to detect capture loss, as this can occur unpredictably despite successful initial placement
- •Both echocardiographic and fluoroscopic guidance can successfully place pacing leads, offering flexibility depending on available resources in your facility
Key Findings
- •Transvenous temporary right ventricular pacing catheters were successfully placed and maintained for 24 hours in all 6 horses without complications using both echocardiographic and fluoroscopic guidance
- •Leads positioned in the right ventricular apex angled caudally showed superior performance with longer time to pacing failure and lower capture thresholds (P < 0.05)
- •Four of six horses experienced varying degrees of loss of capture episodes, while two horses with optimal lead positioning had no pacing failure over 24 hours
- •Medium-term transvenous temporary pacing is feasible for stabilizing horses with symptomatic bradyarrhythmias when combined with continuous ECG monitoring