Atropine vs Isoprenaline in the Invasive Diagnosis of Arrhythmias

Electrophysiological study (EPS) is essential tool for heart rhythm disorders diagnostic. Inducibility of arrhythmia before ablation to confirm the diagnosis and inability to do so after the procedure is crucial for long-term success. Multiple drugs are used to reveal arrhythmias and/or conductive system disorders. Two most often used are atropine and isoprenaline. Atropine is a natural, selective antagonist of cholinergic receptors M1 and M2. It reverses the inhibitory effect of vagal nerve on myocardium. This improves sinus node automatism and conduction in atrioventricular node. Isoprenaline is a preferential agonist of beta-1-adrenergic receptors. It has bathmotropic and chronotropic effect. During daily clinical practice those two drugs are often used interchangeably. However, differences in pharmacokinetics and pharmacodynamics may affect the results. There are lack of data directly comparing those two agents. There are isolated evidences that arrhythmia inducibility rate after the ablation differs between those two drugs. This may lead to the misconception of ablation as successful. The aim of presented study is to evaluate the optimal protocol of pharmacotherapy during EPS.