Atropine vs Isoprenaline in the Invasive Diagnosis of Arrhythmias

Comparison of the Clinical Utility of Atropine and Isoprenaline in the Invasive Diagnosis of Arrhythmias

During electrophysiological study (EPS) multiple drugs are used to reveal arrhythmias and/or conductive system disorders. Two most often used agents are atropine and isoprenaline. Due to their distinct pharmacological properties, they are affecting myocardium in different manner. Those dissimilarities can affect the EPS course and long-term prognosis. The aim of presented study is to evaluate the optimal protocol of pharmacotherapy during EPS.

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.

Patients in whom during electrophysiological study atropine will be used. I.v. bolus of 0.01 mg/kg b.w. will be administered to reach the increase of heart rate of 25% or up to 130/min. If necessary, dose will be increased every 5 minutes until mention above parameters are achieved. Maximum dose will be 0.4 mg/kg b.w.

Patients in whom during electrophysiological study isoprenaline will be used. Continuous i.v. infusion of 0.01 mcg/kg b.w./min will be administered to reach the increase of heart rate of 25% or up to 130/min. If necessary, dose will be doubled every 5 minutes until mention above parameters are achieved. Maximum dose will be 20 mcg/min.

Comparison of heart conductive system and arrhythmia inducibility after using atropine or isoprenaline

Sino-atrial conduction time (ms) during programed atrial stimulation will be assessed to examine the function of sinus node.

Sinus node recovery time (ms) during programed atrial stimulation will be assessed to examine the function of sinus node.

Anterograde Wenkebach point (ms) and effective refractory period of atrioventricular node (ms) during programed atrial stimulation will be assessed.

Retrograde Wenkebach point (ms) and effective refractory period of atrioventricular node (ms) during programed ventricular stimulation will be assessed.

Inducibility of anticipated arrythmia before and after drug administration and after eventual ablation.

Analysis of adverse events during the electrophysiological study according to used drug. Adverse events includes: death, stroke, cardiogenic shock, anaphylaxis, myocardial infarction, electric storm.

Analysis of adverse events during the 12-month follow up according to used drug. Adverse events includes: death, stroke, cardiogenic shock, anaphylaxis, myocardial infarction, electric storm.

Inclusion Criteria: Patients with indication for electrophysiological study according to present guidelines of European Society of Cardiology Exclusion Criteria: Not willing or incapable to give written informed consent. Previous diagnosed ventricle tachycardia or fibrillation Previous diagnosed atrial fibrillation or flutter Glaucoma (contraindication for atropine)

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