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Premont A, Balthes S, Marr CM, Jeevaratnam K. Fundamentals of arrhythmogenic mechanisms and treatment strategies for equine atrial fibrillation. Equine Vet J 2021; 54:262-282. [PMID: 34564902 DOI: 10.1111/evj.13518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 09/13/2021] [Accepted: 09/16/2021] [Indexed: 11/26/2022]
Abstract
Atrial fibrillation (AF) is the most common pathological arrhythmia in horses. Although it is not usually a life-threatening condition on its own, it can cause poor performance and make the horse unsafe to ride. It is a complex multifactorial disease influenced by both genetic and environmental factors including exercise training, comorbidities or ageing. The interactions between all these factors in horses are still not completely understood and the pathophysiology of AF remains poorly defined. Exciting progress has been recently made in equine cardiac electrophysiology in terms of diagnosis and documentation methods such as cardiac mapping, implantable electrocardiogram (ECG) recording devices or computer-based ECG analysis that will hopefully improve our understanding of this disease. The available pharmaceutical and electrophysiological treatments have good efficacy and lead to a good prognosis for AF, but recurrence is a frequent issue that veterinarians have to face. This review aims to summarise our current understanding of equine cardiac electrophysiology and pathophysiology of equine AF while providing an overview of the mechanism of action for currently available treatments for equine AF.
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Affiliation(s)
- Antoine Premont
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - Samantha Balthes
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - Celia M Marr
- Rossdales Equine Hospital and Diagnostic Centre, Newmarket, UK
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Decloedt A, Van Steenkiste G, Vera L, Buhl R, van Loon G. Atrial fibrillation in horses Part 2: Diagnosis, treatment and prognosis. Vet J 2020; 268:105594. [PMID: 33468306 DOI: 10.1016/j.tvjl.2020.105594] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 10/27/2020] [Accepted: 12/10/2020] [Indexed: 10/22/2022]
Abstract
Atrial fibrillation (AF) is suspected by an irregularly irregular rhythm during auscultation at rest and should be confirmed by electrocardiography. Heart rate monitoring is potentially interesting for AF detection by horse owners, based on the disproportionally high heart rate during exercise or increased heart rate variability. Echocardiography and laboratory analysis are useful to identify underlying cardiac disease. Horses with severe cardiac disease should not undergo cardioversion due to the risk of recurrence. Cardioversion is recommended especially in horses performing high intensity exercise or showing average maximal heart rates higher than 220 beats per min or abnormal ventricular complexes during exercise or stress. Pharmacological cardioversion can be performed using quinidine sulphate administered orally, with an overall mean reported success rate around 80%. Other therapeutic drugs have been described such as flecainide, amiodarone or novel atrial specific compounds. Transvenous electrical cardioversion (TVEC) is performed by delivering a shock between two cardioversion catheters positioned in the left pulmonary artery and right atrium, with a success rate of >95%. After cardioversion, most horses return to their previous level of performance. However, the recurrence rate after pharmacological or electrical cardioversion is up to 39%. Recurrence has been related to previous unsuccessful treatment attempts, valvular regurgitation and the presence of atrial premature depolarisations or low atrial contractile function after cardioversion. Large atrial size and long AF duration have also been suggested as risk factors. Different approaches for preventing recurrence have been described such as the administration of sotalol, however, large clinical studies have not been published.
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Affiliation(s)
- Annelies Decloedt
- Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Belgium.
| | - Glenn Van Steenkiste
- Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Belgium
| | - Lisse Vera
- Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Belgium
| | - Rikke Buhl
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Gunther van Loon
- Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Belgium
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3
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Miller SM, Spargo KE. Science-in-brief: Clinical highlights from 50th Congress of the South African Equine Veterinary Association 2017. Equine Vet J 2017; 49:266-268. [DOI: 10.1111/evj.12678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 02/24/2017] [Indexed: 11/26/2022]
Affiliation(s)
- S. M. Miller
- Summerveld Equine Hospital; Summerveld South Africa
- Section Diagnostic Imaging; Department of Companion Animal Clinical Studies, Faculty of Veterinary Science; University of Pretoria, Onderstepoort; Pretoria South Africa
| | - K. E. Spargo
- Section Diagnostic Imaging; Department of Companion Animal Clinical Studies, Faculty of Veterinary Science; University of Pretoria, Onderstepoort; Pretoria South Africa
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Whelchel DD, Tennent-Brown BS, Coleman AE, Rapoport GS, Blas-Machado U, Maisenbacher HW, Credille BC, Giguère S. Treatment of supraventricular tachycardia in a horse. J Vet Emerg Crit Care (San Antonio) 2017; 27:362-368. [DOI: 10.1111/vec.12591] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 06/23/2015] [Accepted: 08/19/2015] [Indexed: 11/29/2022]
Affiliation(s)
| | - Brett S. Tennent-Brown
- Faculty of Veterinary and Agricultural Sciences; University of Melbourne; Werribee VIC 3030 Australia
| | - Amanda E. Coleman
- College of Veterinary Medicine; University of Georgia; Athens GA 30602
| | - Gregg S. Rapoport
- College of Veterinary Medicine; University of Georgia; Athens GA 30602
| | | | | | | | - Steeve Giguère
- College of Veterinary Medicine; University of Georgia; Athens GA 30602
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Potter B, Scansen B, Dunbar L, Reed S, Toribio R. Transcutaneous direct current cardioversion in a foal with lone atrial fibrillation. J Vet Cardiol 2017; 19:99-105. [DOI: 10.1016/j.jvc.2016.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 08/17/2016] [Accepted: 09/06/2016] [Indexed: 10/20/2022]
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Haugaard MM, Pehrson S, Carstensen H, Flethøj M, Hesselkilde EZ, Praestegaard KF, Diness JG, Grunnet M, Jespersen T, Buhl R. Antiarrhythmic and electrophysiologic effects of flecainide on acutely induced atrial fibrillation in healthy horses. J Vet Intern Med 2014; 29:339-47. [PMID: 25328012 PMCID: PMC4858114 DOI: 10.1111/jvim.12496] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 09/02/2014] [Accepted: 10/02/2014] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Only 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. OBJECTIVES To 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. ANIMALS Nine Standardbred horses. Eight received flecainide, 3 were used as time-matched controls, 2 of which also received flecainide. METHODS Prospective 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. RESULTS Flecainide 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 IMPORTANCE Flecainide 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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Affiliation(s)
- M M Haugaard
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark
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Reef VB, Bonagura J, Buhl R, McGurrin MKJ, Schwarzwald CC, van Loon G, Young LE. Recommendations for management of equine athletes with cardiovascular abnormalities. J Vet Intern Med 2014; 28:749-61. [PMID: 24628586 PMCID: PMC4895474 DOI: 10.1111/jvim.12340] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 01/28/2014] [Accepted: 01/28/2014] [Indexed: 11/29/2022] Open
Abstract
Murmurs and arrhythmias are commonly detected in equine athletes. Assessing the relevance of these cardiovascular abnormalities in the performance horse can be challenging. Determining the impact of a cardiovascular disorder on performance, life expectancy, horse and rider or driver safety relative to the owner's future expectations is paramount. A comprehensive assessment of the cardiovascular abnormality detected is essential to determine its severity and achieve these aims. This consensus statement presents a general approach to the assessment of cardiovascular abnormalities, followed by a discussion of the common murmurs and arrhythmias. The description, diagnosis, evaluation, and prognosis are considered for each cardiovascular abnormality. The recommendations presented herein are based on available literature and a consensus of the panelists. While the majority of horses with cardiovascular abnormalities have a useful performance life, periodic reexaminations are indicated for those with clinically relevant cardiovascular disease. Horses with pulmonary hypertension, CHF, or complex ventricular arrhythmias should not be ridden or driven.
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Affiliation(s)
- V B Reef
- Department of Clinical Studies-New Bolton Center, University of Pennsylvania School of Veterinary Medicine, Kennett Square, PA
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Schauvliege S, van Loon G, De Clercq D, Devisscher L, Deprez P, Gasthuys F. Cardiovascular responses to transvenous electrical cardioversion of atrial fibrillation in anaesthetized horses. Vet Anaesth Analg 2009; 36:341-51. [PMID: 19538571 DOI: 10.1111/j.1467-2995.2009.00470.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To examine the influence of direct current shock application in anaesthetized horses with atrial fibrillation (AF) and to study the effects of cardioversion to sinus rhythm (SR). STUDY DESIGN Prospective clinical study. ANIMALS Eight horses successfully treated for AF (transvenous electrical cardioversion after amiodarone pre-treatment). METHODS Cardioversion catheters and a pacing catheter were placed under sedation [detomidine 10 microg kg(-1) intravenously (IV)]. After additional sedation (5-10 microg kg(-1) detomidine, 0.1 mg kg(-1) methadone IV), anaesthesia was induced with ketamine, 2.2 mg kg(-1) and midazolam, 0.06 mg kg(-1) (IV) in a sling and maintained with isoflurane in oxygen. Flunixin meglumine, 1.1 mg kg(-1), was administered IV. Shocks were delivered as biphasic truncated exponential waves, synchronized with the R-wave of the electrocardiogram. Monitoring included pulse oximetry, electrocardiography, capnography, inhalational anaesthetic agent concentration, arterial blood pressure, LiDCO and PulseCO cardiac index (CI) and arterial blood gases. Values before and after the first unsuccessful shock and before and after cardioversion to SR were compared. RESULTS Values before the first shock were comparable to reported values in healthy, isoflurane anaesthetized horses. Reliable CI measurements could not be obtained using the PulseCO technique. Intermittent positive pressure ventilation was required in most horses (bradypnea and/or PaCO(2) >8 kPa, 60 mmHg), while dobutamine was administered in two horses (0.3-0.5 microg kg(-1) minute(-1)). After the 1st unsuccessful shock application, systolic arterial pressure (SAP) was decreased (p = 0.025), other recorded values were not influenced (CI measurements not available for this analysis). SR was associated with increases in CI (p = 0.039) and stroke index (p = 0.002) and a decrease in SAP (p = 0.030). CONCLUSIONS AND CLINICAL RELEVANCE Despite the presence of AF, cardiovascular function was well maintained during anaesthesia and was not affected by shock application. Cardiac index and stroke index increased and SAP decreased after cardioversion.
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Affiliation(s)
- Stijn Schauvliege
- Faculty of Veterinary Medicine, Department of Surgery and Anaesthesia of Domestic Animals, Ghent University, Salisburylaan, Merelbeke, Belgium.
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Jesty S, Kraus M, Gelzer A, Rishniw M, Moïse N. Effect of Transvenous Electrical Cardioversion on Plasma Cardiac Troponin I Concentrations in Horses with Atrial Fibrillation. J Vet Intern Med 2009; 23:1103-7. [DOI: 10.1111/j.1939-1676.2009.0369.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Bellei MHM, Kerr C, McGurrin MKJ, Kenney DG, Physick-Sheard P. Management and complications of anesthesia for transvenous electrical cardioversion of atrial fibrillation in horses: 62 cases (2002-2006). J Am Vet Med Assoc 2007; 231:1225-30. [PMID: 17937553 DOI: 10.2460/javma.231.8.1225] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To describe management of anesthesia for transvenous electrical cardioversion (TVEC) in horses and report perianesthetic complications. DESIGN Retrospective case series. ANIMALS 62 horses with atrial fibrillation and without underlying cardiac disease and 60 horses without atrial fibrillation. PROCEDURES Medical records of horses with atrial fibrillation anesthetized for TVEC were reviewed, as were records of horses without atrial fibrillation anesthetized for magnetic resonance imaging (MRI). The TVEC group horses were compared with MRI group horses for incidence of intraoperative bradycardia and use of inotropic drugs. Data obtained included patient signalment, weight, duration of anesthesia, heart rate and arterial blood pressure during anesthesia, anesthetic drugs administered, mode of ventilation, perioperative complications, and quality of recovery. RESULTS The TVEC group horses were > 1 year of age and were predominantly Standardbreds. The TVEC group horses underwent a total of 76 anesthetic episodes. For 40 (52.6%) anesthetic episodes, horses received xylazine only for premedication, and for 26 (34.2%) anesthetic episodes, horses received xylazine and butorphanol. Induction of anesthesia consisted of ketamine administration in various combinations with diazepam and guaifenesin for 74 (97.4%) anesthetic episodes and ketamine alone for 2 (2.6%). Bradycardia in horses was encountered during 15 of 76 (19.7%) anesthetic episodes. Minor signs of possible postanesthetic myopathy occurred following 6 (7.9%) anesthetic episodes. No significant difference was found between TVEC and MRI group horses regarding incidence of bradycardia and inotropic drug administration. CONCLUSIONS AND CLINICAL RELEVANCE Short-duration anesthesia for TVEC of atrial fibrillation in horses without underlying cardiac disease was a safe procedure.
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Affiliation(s)
- Maria Helena M Bellei
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada
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Transvenous electrical cardioversion of atrial fibrillation in six horses using custom made cardioversion catheters. Vet J 2007; 177:198-204. [PMID: 17920965 DOI: 10.1016/j.tvjl.2007.08.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Revised: 08/10/2007] [Accepted: 08/18/2007] [Indexed: 11/23/2022]
Abstract
Pharmacological conversion of atrial fibrillation (AF) to sinus rhythm in horses can be difficult. The objective of this study was to investigate the feasibility of transvenous electrical cardioversion with custom made catheters in eight horses, of which three had failed cardioversion using quinidine sulfate. Two cardioversion catheters and one pacing/sensing electrode were inserted via the right jugular vein and placed using ultrasound guidance into the left pulmonary artery, the right atrium and the right ventricle, respectively. Because immediate recurrence of AF was encountered in the second horse treated, pre-treatment with amiodarone was given to each of the remaining six horses. Induction of general anaesthesia was associated with dislocation of the cardioversion catheter in three horses, requiring a second catheterisation procedure. During general anaesthesia, biphasic R wave synchronised shocks of up to 360 J were delivered between both cardioversion electrodes. In six horses (75%), including two which had failed quinidine sulfate treatment, sinus rhythm was restored with a mean energy level of 295+/-62 J. No side effects were observed. Blood analysis 3 h after cardioversion revealed normal parameters, including cardiac troponin I values. Transvenous electrical cardioversion of atrial fibrillation with custom made cardioversion catheters can be considered as a treatment option for atrial fibrillation in horses, especially when conventional drugs fail.
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De Clercq D, van Loon G, Baert K, Tavernier R, Croubels S, De Backer P, Deprez P. Effects of an adapted intravenous amiodarone treatment protocol in horses with atrial fibrillation. Equine Vet J 2007; 39:344-9. [PMID: 17722727 DOI: 10.2746/042516407x182811] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASON FOR PERFORMING STUDY Good results have been obtained with a human amiodarone (AD) i.v. protocol in horses with chronic atrial fibrillation (AF) and a pharmacokinetic study is required for a specific i.v. amiodarone treatment protocol for horses. OBJECTIVES To study the efficacy of this pharmacokinetic based i.v. AD protocol in horses with chronic AF. METHODS Six horses with chronic AF were treated with an adapted AD infusion protocol. The protocol consisted of 2 phases with a loading dose followed by a maintenance infusion. In the first phase, horses received an infusion of 6.52 mg AD/kg bwt/h for 1 h followed by 1.1 mg/kg bwt/h for 47 h. In the second phase, horses received a second loading dose of 3.74 mg AD/kg bwt/h for 1 h followed by 1.31 mg/kg bwt/h for 47 h. Clinical signs were monitored, a surface ECG and an intra-atrial electrogram were recorded. AD treatment was discontinued when conversion or any side effects were observed. RESULTS Three of the 6 horses cardioverted successfully without side effects. The other 3 horses did not convert and showed adverse effects, including diarrhoea. In the latter, there were no important circulatory problems, but the diarrhoea continued for 10-14 days. The third horse had to be subjected to euthanasia because a concomitant Salmonella infection worsened the clinical signs. CONCLUSION The applied treatment protocol based upon pharmacokinetic data achieved clinically relevant concentrations of AD and desethylamiodarone. POTENTIAL RELEVANCE Intravenous AD has the potential to be an alternative pharmacological treatment for AF in horses, although AD may lead to adverse drug effects, particularly with cumulative dosing.
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Affiliation(s)
- D De Clercq
- Department of Large Animal Internal Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
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De Clercq D, van Loon G, Baert K, Tavernier R, Croubels S, De Backer P, Deprez P. Intravenous amiodarone treatment in horses with chronic atrial fibrillation. Vet J 2006; 172:129-34. [PMID: 15908245 DOI: 10.1016/j.tvjl.2005.04.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Six horses without underlying cardiac disease were presented because of atrial fibrillation of between 5 and 12 months duration. These horses received an intravenous amiodarone treatment of 5mg/kg/h for 1 h followed by 0.83mg/kg/h for 23h and subsequently 1.9mg/kg/h for 30h. During treatment, clinical signs were monitored and a surface ECG and an intra-atrial electrogram were recorded. Infusion was discontinued when sinus rhythm or side effects occurred. Four horses successfully cardioverted, of which one showed symptoms of hind limb weakness and weight shifting. Two horses did not cardiovert and showed similar side effects. In all horses, side effects disappeared within 6h after termination of treatment. Cardiac side effects, such as pro-arrhythmia, were not seen in any of the horses. Total bilirubin slightly increased in three horses and normalised within four days. It was concluded that amiodarone has the potential to treat naturally occurring chronic atrial fibrillation in horses, although further research is needed to refine the infusion protocol.
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Affiliation(s)
- D De Clercq
- Department of Large Animal Internal Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
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De Clercq D, Baert K, Croubels S, van Loon G, Maes A, Tavernier R, Deprez P, De Backer P. Evaluation of the pharmacokinetics and bioavailability of intravenously and orally administered amiodarone in horses. Am J Vet Res 2006; 67:448-54. [PMID: 16506906 DOI: 10.2460/ajvr.67.3.448] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the clinical effects and pharmacokinetics of amiodarone after single doses of 5 mg/kg administered orally or intravenously. ANIMALS 6 healthy adult horses. PROCEDURE In a cross over study, clinical signs and electrocardiographic variables were monitored and plasma and urine samples were collected. A liquid chromatography-mass spectrometry method was used to determine the percentage of protein binding and to measure plasma and urine concentrations of amiodarone and the active metabolite desethylamiodarone. RESULTS No adverse clinical signs were observed. After IV administration, median terminal elimination half-lives of amiodarone and desethylamiodarone were 51.1 and 75.3 hours, respectively. Clearance was 0.35 L/kg x h, and the apparent volume of distribution for amiodarone was 31.1 L/kg. The peak plasma desethylamiodarone concentration of 0.08 microg/mL was attained 2.7 hours after IV administration. Neither parent drug nor metabolite was detected in urine, and protein binding of amiodarone was 96%. After oral administration of amiodarone, absorption of amiodarone was slow and variable; bioavailability ranged from 6.0% to 33.7%. The peak plasma amiodarone concentration of 0.14 microg/mL was attained 7.0 hours after oral administration and the peak plasma desethylamiodarone concentration of 0.03 microg/mL was attained 8.0 hours after administration. Median elimination half-lives of amiodarone and desethylamiodarone were 24.1 and 58.6 hours, respectively. CONCLUSION AND CLINICAL RELEVANCE Results indicate that the pharmacokinetic distribution of amiodarone is multicompartmental. This information is useful for determining treatment regimens for horses with arrythmias. Amiodarone has low bioavailability after oral administration, does not undergo renal excretion, and is highly protein-bound in horses.
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Affiliation(s)
- Dominique De Clercq
- Department of Large Animal Internal Medicine, Ghent University, Salisburylaan 133, B-9820, Merelbeke, Belgium
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How to perform transvenous electrical cardioversion in horses with atrial fibrillation. J Vet Cardiol 2005; 7:109-19. [PMID: 19083326 DOI: 10.1016/j.jvc.2005.09.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Accepted: 09/01/2005] [Indexed: 11/20/2022]
Abstract
Electrical cardioversion of atrial fibrillation is a well-established technique for restoration of sinus rhythm in humans. While transthoracic cardioversion is more commonly used, transvenous electrical cardioversion (TVEC) has been reported as having higher efficacy at substantially lower energy levels. In horses, treatment of atrial fibrillation has essentially been limited to the administration of quinidine salts either orally or intravenously. TVEC provides an alternative to quinidine salts, especially for those animals in which quinidine is neither effective nor tolerated. The present report details this technique in horses, discusses possible complications of the procedure, and provides guidance for successful outcome. Still and video images are used to illustrate details with regard to TVEC techniques in horses. Please view supplemental material for the videos.
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van Loon G, De Clercq D, Tavernier R, Amory H, Deprez P. Transient complete atrioventricular block following transvenous electrical cardioversion of atrial fibrillation in a horse. Vet J 2005; 170:124-7. [PMID: 15993796 DOI: 10.1016/j.tvjl.2004.08.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2004] [Indexed: 11/27/2022]
Abstract
Transvenous electrical cardioversion was attempted in a horse with drug refractory atrial fibrillation. A temporary pacing catheter and two defibrillation catheters were inserted transvenously into the right ventricular apex, the right atrium and the pulmonary artery, respectively. Under general anaesthesia 100, 200, 300 and 360 J monophasic shocks were delivered between both defibrillation catheters but sinus rhythm could not be restored. Immediately after the 200, 300 and 360 J shock, transient third-degree atrioventricular block occurred for a period of, respectively, 15, 40 and 55 s. These periods of profound bradycardia were corrected by temporary right ventricular pacing until spontaneous conduction resumed. It is concluded that temporary right ventricular pacing should be available during electrical cardioversion of atrial fibrillation in horses.
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Affiliation(s)
- G van Loon
- Large Animal Internal Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
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Kimberly M, McGurrin J, Physick-Sheard PW, Kenney DG, Kerr C, Hanna WB. Transvenous Electrical Cardioversion of Equine Atrial Fibrillation Technical Considerations. J Vet Intern Med 2005. [DOI: 10.1111/j.1939-1676.2005.tb02748.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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