Single-Chamber Cardiac Pacemaker Implantation in a Donkey with Complete AV Block: A Long-Term Follow-Up

Abstract

A five-month-old African jenny was presented with a history of exercise intolerance and syncopal episodes. Severe bradycardic arrhythmia due to a high-grade second-degree atrioventricular (AV) block with progression to complete AV block was diagnosed. The jenny underwent a transvenous single-chamber pacemaker implantation. The implantation procedure was performed in a lateral recumbency and the ventricular lead was inserted through the jugular vein. Positioning of the lead was guided by echocardiography. The pacemaker was programmed to VVI mode with a minimal ventricular rate of 40 pulses per minute, a pulse amplitude of 2.4 V, a pulse width of 0.5 ms and sensing amplitude of 2.5 mV. Short-term complications associated with the procedure included lead dislodgement and pacemaker pocket infection. The long-term outcome was satisfactory; the jenny showed improvement in heart function and quality of life after pacemaker implantation. The pulse generator replacement was performed twice (at nine-year intervals) and the intervention was always associated with a local inflammatory reaction around the pacing device. Cardiac examination 18 years after pacemaker implantation revealed no morphological changes in the heart; the electrode lead was still in the correct position and successful pacing and sensing of the ventricle were obtained. Regular follow-up checks are important to evaluate pacemaker function.

Successful application of closed loop stimulation pacemakers with remote monitoring in 3 miniature donkeys with syncope

“…The cause of their third‐degree AV block was not known, but a genetic predisposition has been suggested. 16 , 17 Intermittent AV conduction with abnormal QRS morphology, possibly caused by bundle branch block, and paroxysmal ventricular tachycardia also were identified. Two donkeys were diagnosed with aortic root aneurysm several centimeters distal to the aortic valve, which remained stable during the follow‐up period (3 and 6 years).…”

“…In this report, all of the donkeys were miniature donkeys. The cause of their third‐degree AV block was not known, but a genetic predisposition has been suggested 16,17 . Intermittent AV conduction with abnormal QRS morphology, possibly caused by bundle branch block, and paroxysmal ventricular tachycardia also were identified.…”

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

“…The critical moment of pacemaker implantation in large animals lies on the placement of a transvenous temporary pacemaker, if possible, before the administration of any sedative drugs. Sedlinská et al 8 reported several episodes of asystole requiring indirect cardiac massage in a 5-month-old donkey undergoing pacemaker implantation and in which t e m p o r a ryp a c i n gw a sn o tp o s s i b l e .T h eu s eo fat e m p o r a ry cardiac pacemaker before anaesthesia will allow emergency pacing in the situation of severe bradycardia or asystole 1,5,8 and remains the only method for temporary pacing in adult equids, as transcutaneous external pacing is limited by the size of the animal. A further advantage of transvenous pacing is the possibility for pacing on the awake standing animal, wh e r ea sth i si sn o tpo s s i b l eu s i n gatr a n scu ta n eo u sm e th od .…”

“…The critical moment of pacemaker implantation in large animals lies on the placement of a transvenous temporary pacemaker, if possible, before the administration of any sedative drugs. Sedlinská et al 8 . reported several episodes of asystole requiring indirect cardiac massage in a 5‐month‐old donkey undergoing pacemaker implantation and in which temporary pacing was not possible.…”

“…Transvenous implantation of the pacemaker under fluoroscopy guidance was performed using the technique reported by van Loon et al 14,15 and used in Sedlinská et al 8 No anaesthetic complications occurred during the intervention. Thirty minutes before the end of anaesthesia, lidocaine CRI was discontinued, and morphine (Morphin HCl Sintetica 10 mg/ml; Sintetica SA) 0.1 mg/kg was administered intramuscularly.…”