THE "NEW FRONTIERS" OF ARRHYTHMIAS 1998

RT-34	The clinical spectrum of adenosine-sensitive syncope


Carlo Menozzi, Michele Brignole, Germano Gaggioli, Lorella Gianfranchi, Angelo Bartoletti, Nicola Bottoni, Gino Lolli, Daniele Oddone, Attilio Del Rosso, Giuseppe Pellinghelli. Sections of Arrhythmology, Ospedale S. Maria Nuova, Reggio Emilia, Ospedali Riuniti, Lavagna, Italy

Abstract
	An increased susceptibility of the atrioventricular node to adenosine might play a role in the genesis of some cases of syncope. A bolus injection of ATP caused asystolic pauses > 6000 ms due to atrioventricular block in 28% of 60 patients with syncope of unexplained origin and in 5% of 90 control subjects without syncope (p = 0.000). Among 24 patients who had the fortuitous electrocardiographic recording of a spontaneous asystolic syncope, the ATP test was positive in 86% of the 7 patients with documented atrioventricular block of unknown etiology, in 25% of the 8 patients with documented atrioventricular block of known etiology and in 0% of the 9 patients with documented sinus arrest. Thus, an abnormal response to ATP testing suggests the diagnosis of syncope due to paroxysmal atrioventricular block. The clinical spectrum of adenosine-sensitive syncope seems to differentiate them from neurally-mediated syncope.
Key Words
	Syncope adenosine triphosphate sensitivity, atrio-ventricular conduction, OA

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