Halothane Increases Myocardial Sensitivity to Epinephrine-Induced Arrhythmias in Cirrhotic Rats

Abstract

Background: Cirrhotic patients are at a greater risk of different kinds of arrhythmias. Despite the well-known arrhythmogenic effects of halothane, developing countries continue to use halothane due to its low cost. This study was designed to investigate the pathophysiology of halothane untoward effects on heart rhythm moreover was aimed to explore the effect of halothane anesthesia on the threshold of epinephrine-induced arrhythmia in cirrhotic rats. Methods: Bile duct ligation was used to induce cirrhosis. The subjects were anesthetized with halothane or pentobarbital. Arrhythmia was induced by intravenous injections of increasing doses of epinephrine. Blood pressure and the electrocardiogram were monitored. The threshold doses of epinephrine for induction of premature ventricular contraction (PVC), ventricular tachycardia (VT) and ventricular fibrillation (VF) were determined. Results: Cirrhotic rats had longer QTc intervals in comparison with sham-operated animals. Halothane-anesthetized rats had significantly shorter QTc intervals than pentobarbital-anesthetized rats in both cirrhotic and sham-operated groups. Halothane significantly decreased the threshold dose of epinephrine for induction of PVC, VT and VF in cirrhotic rats. The BP of different experimental groups did not differ with each other. Conclusion: Cirrhosis intensifies halothane induced ventricular arrhythmia and our results raise concerns regarding the use of halothane in cirrhotic patients.

Keywords

• cirrhosis
• anesthesia
• halothane
• epinephrine-induced arrhythmias
• rats