Nonsustained polymorphic ventricular tachycardia during adenosine stress perfusion imaging in the setting of resting pre-excitation electrocardiographic pattern: should we be avoiding adenosine pharmacologic stress testing in pre-excitation syndromes

摘要

Background. Adenosine is an endogenous nucleoside that is ubiquitous within the human body. It is a nonselective A2 receptor antagonist. Through its action on the A2A receptor, adenosine induces direct coronary arteriolar vasodilatation and is well suited as a pharmacologic agent in the assessment of myocardial ischemia.Adenosine is known to have a very favorable and excellent safety profile. Through its other actions on the Aj, A2B, and A3 receptors, it can produce some uncommon yet serious side effects. These include high-grade atrioventricular (AV) block, hypotension (through its vasodilatory properties on the peripheral vasculature), and severe bronchospasm (and therefore is contraindi-cated in patients with severe reactive airway disease). Because of its extremely short half-life (approximately 5 seconds), these effects usually spontaneously resolve upon cessation of the adenosine infusion.We describe a case of sudden onset of nonsustained polymorphic ventricular tachycardia in a patient with known Wolff-Parkinson-White (WPW) pattern (delta wave) on resting electrocardiogram (ECG) during adenosine infusion for a myocardial perfusion study. This case report raises questions as to whether pre-excitation pattern or syndromes should be considered a contraindication for adenosine stress perfusion imaging.