The therapeutic and diagnostic cardiac electrophysiological uses of adenosine

Abstract

Adenosine is a purine nucleoside with a rapid onset and brief duration of action after intravenous bolus administration. Its most prominent cardiac effect is impairment or blockade of atrioventricular nodal conduction, but other effects are depression of automaticity of the sinus node and attenuation of catecholamine-related ventricular after-depolarizations. The cardiac cell surface receptor is the A1 purinoceptor. The therapeutic value of adenosine is predominantly in those arrhythmias in which the atrioventricular node forms part of a reentry circuit, as clearly demonstrated by the high success rate for termination of atrioventricular nodal reentry tachycardia and of atrioventricular reentry tachycardia involving an accessory pathway in the Wolff-Parkinson-White syndrome. Ventricular tachycardias are generally unresponsive, with the exception of right ventricular outflow tract tachycardia. A diagnostic role has emerged for adenosine. The transient blockade of the atrioventricular node that it causes can reveal important electrocardiographic features in arrhythmias, such as atrial flutter, or can unmask latent preexcitation. In wide-QRS tachycardias, adenosine can help to distinguish ventricular tachycardia from supraventricular tachycardia with QRS aberration. Unlike verapamil, adenosine is safe in ventricular tachycardia. A suggested dosing scheme is to give incremental doses at 1-minute intervals, starting at 0.05 mg/kg and continuing until complete atrioventricular block is induced or a maximum of 0.25 mg/kg is reached. Side effects are transient, sometimes uncomfortable, and not hazardous; dyspnea and chest discomfort are most frequent. A history of asthma is a relative contraindication. Aminophylline antagonizes and dipyridamole potentiates the effects of adenosine.

Use of Adenosine Test for the Exclusion of Preexcitation Syndrome in Asymptomatic Individuals

“…The major limitation of this study is the fact that the subjects did not undergo EPS as a definitive method to rule out an inapparent pathway. Yet, as previous studies documented a good correlation between EPS results and adenosine test, 2–10 we believe that it may be relied upon as a noninvasive alternative to EPS in a population such as the one in our study.…”

“…Adenosine is widely used to treat reentry tachycardia involving the AV node because of its rapid onset and brief duration of action when given as an intravenous bolus 2 . Adenosine can transiently inhibit conduction through the AV node during sinus rhythm, but usually does not slow conduction through an accessory pathway and may help in the unmasking of an inapparent accessory pathway.…”

Atrial Fibrillation Induction in a Pediatric Patient during Adenosine Administration

“…While the therapeutic utility of adenosine is documented for patients in a narrow complex tachycardia, potential acute adverse effects of the medication have been described in pediatric patients, including induction of atrial fibrillation, accelerated ventricular tachycardia, apnea, and asystole lasting up to one minute [3]. Atrial fibrillation in this setting is usually transient and not sustained [1]. An acute shortening of the atrial refractory period has been proposed as the mechanism by which adenosine can precipitate atrial fibrillation [4].…”

Adenosine‐induced complete heart block: Not so transient

“…The therapeutic value of adenosine is predominately in those arrhythmias in which the atrioventricular node forms part of a re‐entry circuit, as demonstrated by the high success rate for termination of atrioventricular nodal re‐entry tachycardia and of atrioventricular re‐entry tachycardia involving an accessory pathway in the Wolf–Parkinson–White syndrome. Ventricular tachycardias are generally unresponsive with the exception of right ventricular outflow tract tachycardia 3 …”