Resuscitation of an anaesthetised foal with uroperitoneum and ventricular asystole

A 2‐day‐old male Quarter Horse foal was diagnosed with uroperitoneum and ruptured bladder. Intravenous fluid therapy was initiated prior to anaesthesia and repeated unsuccessful attempts were made to drain the abdomen of accumulated urine. Prior to anaesthesia the foal exhibited clinical signs of abdominal compartment syndrome. When anaesthetised the accumulated urine was drained by free flow through a small abdominal stab incision after aseptic site preparation. A few minutes later electrocardiography indicated second degree atrioventricular block which progressed into third degree atrioventricular block and ventricular asystole. The foal was resuscitated by closed chest compressions, mechanical ventilation, sympathomimetic and antimuscarinergic drugs. When anaesthetising these neonatal patients one must be prepared to handle potentially fatal cardiac arrhythmias and, prior to surgery, the danger posed by increased intra‐abdominal pressure should be weighed against the need for diluting plasma potassium.     

松针挥发油对乌头碱诱发大鼠心律失常的影响

为了测定松针挥发油对乌头碱诱发大鼠心律失常的影响,采用静脉注射乌头碱复制大鼠心律失常的动物模型,观察灌胃给药松针挥发油对抗乌头碱诱发大鼠心律失常的作用。结果发现,松针挥发油的低、中、高剂量可显著延迟VP(室性早博)和VT(室性心动过速)的出现(与阴性对照组对比P0.01、P0.05),而以中剂量效果最好(与阴性对照组对比P0.01)。阳性对照组普罗帕酮对VT(室性心动过速)和VF(心室纤颤)的出现具显著延迟作用(与阴性对照组对比P0.01),但对VP的出现与阴性对照组相比却无显著差别(P0.05)。说明松针挥发油对药物诱发的心律失常具对抗作用。     

Intracardiac electrophysiological conduction parameters in adult dogs

Background: Invasive electrophysiology study (EPS) is one of the most important adjunct tests for the evaluation of arrhythmias in human medicine. However, EPS is neither well known nor widely used in veterinary medicine.

Objective: To define the values for intracardiac conduction parameters determined during invasive EPS in dogs.

Animals and methods: The study included 16 admitted dogs of various breeds, sex and ages and 6 control Beagles. In the Beagles, EPS was performed twice at 6-month intervals in order to verify the reproducibility of the results.

Results: No significant differences were found between the results of the baseline and repeated EPS performed in the Beagles. We found retrograde conduction in 13 (59%) out of 22 dogs and including 4 (31%) animals with concomitant ‘jumps’ in the atrioventricular node conduction curve, pointing to the presence of dual conduction in this node. The mean values of the AV and retrograde VA Wenckebach points equaled to 220 and 360 ms, respectively, suggesting that the capability of the descending route is higher than that of the ascending route.

Conclusion: The values determined in this study may be helpful in early detection of abnormalities in the electrical conduction system of the heart.     

Atrial fibrillation management in a breeding stallion

A 20-year-old warmblood breeding stallion presented to a University practice for semen collection and evaluation was incidentally diagnosed with atrial fibrillation (AF). Electrocardiogram recordings during breeding revealed inappropriately rapid tachycardia and occasional ventricular premature depolarizations/aberrant ventricular conduction. Transvenous electrical cardioversion was performed. After successful cardioversion the horse displayed supraventricular ectopy and atrial contractile dysfunction and was administered sotalol hydrochloride in an attempt to decrease the risk of AF recurrence. Supraventricular ectopy and echocardiographic evidence of atrial dysfunction gradually improved and normalized over 6 months. No direct adverse effects of the chronic anti-arrhythmic treatment were observed and libido and semen quality were unaffected. AF recurred 6 months after cardioversion and sotalol therapy was continued to control the ventricular ectopy/aberrant ventricular conduction during semen collection. Considerations regarding pathologic arrhythmias and inappropriately high heart rates in breeding stallions with AF may be similar to those in riding horses. Sotalol hydrochloride was a safe anti-arrhythmic drug in the management of this case.     

Transvenous electrical cardioversion of atrial fibrillation in horses: Horse and procedural factors correlated with success and recurrence

BackgroundTransvenous electrical cardioversion (TVEC) is 1 of the main treatment options for atrial fibrillation (AF) in horses. Large‐scale studies on factors affecting success and prognosis have primarily been performed in Standardbred populations.Hypothesis/ObjectivesTo determine factors affecting cardioversion success, cardioversion difficulty and recurrence in a predominant Warmblood study sample.AnimalsTVEC records of 199 horses.MethodsRetrospective study of TVEC procedures of horses admitted for AF without severe echocardiographic abnormalities. Horse and procedural factors for success and cumulative amount of energy (≤ 600 J vs > 600 J) were determined using multivariable logistic regression. A survival analysis was performed to determine risk factors for recurrence.ResultsTwo hundred and thirty‐one TVEC procedures were included, with a 94.4% success rate and 31.9% recurrence rate (51/160). Mitral regurgitation (OR 0.151, 95% CI 0.032‐0.715, P = .02) and AF cycle length (OR 1.05, 95% CI 1.01‐1.09, P = .02) were independent determinants for success. Catheter type (OR 0.154, 95% CI 0.074‐0.322, P < .001), previous AF episode (OR 3.10, 95% CI 1.20‐8.01, P = .02), tricuspid regurgitation (OR 2.54, 95% CI 1.25‐5.13, P = .01), and body weight (OR 1.009, 95% CI 1.003‐1.015, P = .004) were significantly correlated with cumulative amount of energy delivered. Significant risk factors for recurrence after a first AF episode were sex (stallion; HR 3.05, 95% CI 1.34‐6.95, P = .008), mitral regurgitation (HR 1.91, 95% CI 1.08‐3.38, P = .03), and AF duration (HR 1.001, 95% CI 1.0001‐1.0026, P = .04).Conclusions and Clinical ImportanceBoth horse and procedural factors should be considered when assessing treatment options and prognosis in horses with AF.