An Equine Model of Chronic Atrial Fibrillation: Methodology

Loon, Gunther van; Duytschaever, Mattias; Tavernier, René; Fonteyne, W.; Jordaens, Luc; Deprez, Piet

doi:10.1053/tvjl.2001.0668

Cited by 39 publications

(22 citation statements)

References 28 publications

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“…When these criteria are fulfilled, treatment with flecainide demonstrates cardioversion rates of 57–92% in human patients with AF of short duration 32. Flecainide terminated all AF episodes in the present study with a termination time comparable to that observed in previous studies,1, 27 and at the evaluated stimulation rates, the presented baseline values of aERP in horses were consistent with those reported by others 4, 33. Our study identified no flecainide‐induced changes in aERP, indicating that flecainide did not have an influence on atrial repolarization at the chosen stimulation rates.…”

Section: Discussionsupporting

confidence: 91%

Antiarrhythmic and Electrophysiologic Effects of Flecainide on Acutely Induced Atrial Fibrillation in Healthy Horses

Haugaard

Pehrson

Carstensen

et al. 2014

Veterinary Internal Medicne

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BackgroundOnly few pharmacologic compounds have been validated for treatment of atrial fibrillation (AF) in horses. Studies investigating the utility and safety of flecainide to treat AF in horses have produced conflicting results, and the antiarrhythmic mechanisms of flecainide are not fully understood.ObjectivesTo study the potential of flecainide to terminate acutely induced AF of short duration (≥15 minutes), to examine flecainide‐induced changes in AF duration and AF vulnerability, and to investigate the in vivo effects of flecainide on right atrial effective refractory period, AF cycle length, and ventricular depolarization and repolarization.AnimalsNine Standardbred horses. Eight received flecainide, 3 were used as time‐matched controls, 2 of which also received flecainide.MethodsProspective study. The antiarrhythmic and electrophysiologic effects of flecainide were based on 5 parameters: ability to terminate acute pacing‐induced AF (≥15 minutes), and drug‐induced changes in atrial effective refractory period, AF duration, AF vulnerability, and ventricular depolarization and repolarization times. Parameters were assessed at baseline and after flecainide by programmed electrical stimulation methods.ResultsFlecainide terminated all acutely induced AF episodes (n = 7); (AF duration, 21 ± 5 minutes) and significantly decreased the AF duration, but neither altered atrial effective refractory period nor AF vulnerability significantly. Ventricular repolarization time was prolonged between 8 and 20 minutes after initiation of flecainide infusion, but no ventricular arrhythmias were detected.Conclusions and Clinical ImportanceFlecainide had clear antiarrhythmic properties in terminating acute pacing‐induced AF, but showed no protective properties against immediate reinduction of AF. Flecainide caused temporary prolongation in the ventricular repolarization, which may be a proarrhythmic effect.

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Section: Discussionsupporting

confidence: 91%

Antiarrhythmic and Electrophysiologic Effects of Flecainide on Acutely Induced Atrial Fibrillation in Healthy Horses

Haugaard

Pehrson

Carstensen

et al. 2014

Veterinary Internal Medicne

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“…The determination of AERP has been described in horses by programmed electrical stimulation [15,16]. However, the invasive approach using a catheter introduced through the jugular vein allows only right atrial measurements.…”

Section: Discussionmentioning

confidence: 99%

“…This acts as a protective mechanism against intracellular Ca 2+ overload [14]. Programmed electrical stimulation allows quantification of the AERP in order to assess the degree of electrical remodelling [15,16]. However, atrial programmed electrical stimulation can be performed during sinus rhythm but not during AF.…”

Section: Introductionmentioning

confidence: 99%

Noninvasive determination of atrial fibrillation cycle length by atrial colour tissue Doppler imaging in horses

Decloedt

Clercq

Vekens

et al. 2013

Equine Veterinary Journal

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“…In all horses, a dual chamber pacemaker, a a neurostimulator, b and leads c were implanted as described previously by van Loon et al 19 With the neurostimulator, intermittent burst pacing (1 second; 3 times threshold; 20 Hz, every 2 seconds) was applied to induce bouts of AF. The dual chamber pacemaker was used to study atrial and ventricular electrophysiology.…”

Section: Methodsmentioning

confidence: 99%

Atrial and Ventricular Electrical and Contractile Remodeling and Reverse Remodeling Owing to Short‐Term Pacing‐Induced Atrial Fibrillation in Horses

Clercq

Loon

Tavernier

et al. 2008

Veterinary Internal Medicne

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Background: In humans, atrial fibrillation (AF) induces electrical, contractile, and structural remodeling leading to AF stabilization. Little is known about AF-induced atrial remodeling in horses.Hypothesis: Induced AF produces rapid atrial electrical and contractile remodeling in horses. Animals: Six horses, 5 animals completed the study. Methods: Each horse was instrumented with a pulse generator and pacemaker to maintain AF by burst pacing and to study atrial and ventricular electrophysiology (AF cycle length [AFCL], AF duration, and atrial/ventricular effective refractory period [AERP/VERP] at different pacing cycle lengths [PCL]). Left atrial and ventricular contractile remodeling were assessed echocardiographically by calculation of fractional changes in atrial and ventricular dimensions, respectively, during the cardiac cycle. Measurements were performed at baseline, a 7-day AF period and a 2-day recovery period.Results: Atrial electrical and contractile remodeling could be demonstrated after 4 and 12 hours of AF, respectively. A progressive shortening of the AERP (261 AE 39-171 AE 18 ms at a PCL of 1,000 ms, P o .0001), an attenuation of the AERP rate adaptation, a decrease in AFCL (239 AE 39-194 AE 7 ms, P o .0001), and a decrease in atrial FS (12 AE 3% to 0 AE 2%, P o .05) occurred. AF duration increased progressively and became persistent in 2 animals. VERP did not change significantly. Upon restoration of sinus rhythm, values returned to baseline within 48 hours.Conclusions and Clinical Importance: Atrial electrical and contractile remodeling appears rapidly. After 7 days of AF, reverse remodeling occurred within 2 days. These observations suggest that early conversion of AF might be beneficial for success rate and early return to training.

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An Equine Model of Chronic Atrial Fibrillation: Methodology

Cited by 39 publications

References 28 publications

Antiarrhythmic and Electrophysiologic Effects of Flecainide on Acutely Induced Atrial Fibrillation in Healthy Horses

Antiarrhythmic and Electrophysiologic Effects of Flecainide on Acutely Induced Atrial Fibrillation in Healthy Horses

Noninvasive determination of atrial fibrillation cycle length by atrial colour tissue Doppler imaging in horses

Atrial and Ventricular Electrical and Contractile Remodeling and Reverse Remodeling Owing to Short‐Term Pacing‐Induced Atrial Fibrillation in Horses

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