The anaesthetized rabbit with acute atrioventricular block provides a new model for detecting drug-induced Torsade de Pointes.

Background And Purpose: Several rabbit proarrhythmia models have been developed using genetic or pharmacological methods to suppress the slow component of delayed rectifier K currents in the ventricle, leading to reduction of the repolarization reserve. Here we have characterized a novel rabbit in vivo proarrhythmia model with severe bradycardia caused by acute atrioventricular block (AVB).

Experimental Approach: Bradycardia was induced in isoflurane-anaesthetized rabbits by inducing AVB with catheter ablation, and the ventricle was electrically driven at 60 beats min throughout the experiment except when extrasystoles appeared.