Anaesthesia management of transvenous implantation of a single‐chamber, rate‐adaptive pacemaker in a donkey with high‐grade second and third degree atrioventricular block

Abstract

A 17-year-old, domestic, entire, male, miniature donkey with a history of syncope because of sinus bradycardia, high-grade second degree and occasional third degree atrioventricular block was referred for pacemaker implantation under general anaesthesia. After local anaesthesia with topical EMLA cream and subcutaneous mepivacaine infiltration and following tranquilisation with intravenous acepromazine, a temporary pacing catheter was inserted via introducer catheter through the left jugular vein into the right ventricle's apex. After initiation of internal pacing, medetomidine and butorphanol were administered intravenously, followed by ketamine and diazepam. Maintenance of anaesthesia was with isoflurane combined with medetomidine and lidocaine constant-rate infusions. Intramuscular morphine and intravenous medetomidine were administered for recovery. The procedure was uneventful with no anaesthesia-related complications, and manually assisted recovery was smooth. The present report describes the anaesthetic challenges and management of pacemaker implantation under general anaesthesia in a miniature donkey.

Treatment of a Paroxysmal Atrioventricular Block by Implantation of a Bipolar, Single-Chamber Cardiac Pacemaker in a Donkey

“…Single episodes without any ventricular contraction lasted up to 55 s. Commonly, a ventricular escape rhythm guarantees a minimal ventricular rhythm of 15 to 25 beats/minute [1]; this, however, was not the case in this donkey. In the case of previously described intermittent symptomatic bradycardia, an insufficient escape rhythm was the cause of syncope [5,7,9], whereas an escape rhythm was not present in the described case. Paroxysmal atrioventricular blocks are described in human medicine and are characterized by the spontaneous onset of a complete AVB without ventricular contractions [3].…”

Twenty‐four hour continuous transvenous temporary right ventricular pacing in healthy horses

“…Permanent pacemaker implantation is often not immediately available because of numerous considerations, including cost and the possible requirements for general anesthesia or heavy sedation, highly trained personnel, and specialized equipment. 15,16,19,22 In contrast, the equipment for transvenous temporary cardiac pacing (TV-TP) is inexpensive and readily obtained. There are few reports of TV-TP in equids.…”

“…There are few reports of TV-TP in equids. These briefly describe short-term (<4 h) TV-TP during permanent pacemaker implantation, 15,16,19,22 or for treatment of transient asystole after electrical cardioversion under general anesthesia. 32 Reported challenges of TV-TP in horses include maintaining electrode position and achieving consistent capture.…”

“…[10][11][12][13][14] In equids, permanent cardiac pacing has been reported for third-degree atrioventricular block, sick sinus syndrome, advanced second-degree atrioventricular block, sinus arrest, and marked sinus bradycardia. [15][16][17][18][19][20][21][22] Horses presenting with these bradyarrhythmias frequently show signs of poor perfusion, are unstable, and at risk of cardiac failure and death. 17,19,23,24 This is distressing to owners and presents a safety issue to veterinary staff.…”

“…Cardiac pacing is the treatment of choice for symptomatic bradyarrhythmias in humans 1‐9 and dogs 10‐14 . In equids, permanent cardiac pacing has been reported for third‐degree atrioventricular block, sick sinus syndrome, advanced second‐degree atrioventricular block, sinus arrest, and marked sinus bradycardia 15‐22 . Horses presenting with these bradyarrhythmias frequently show signs of poor perfusion, are unstable, and at risk of cardiac failure and death 17,19,23,24 .…”