[The ajmaline test in identifying patients at high risk of developing complete paroxysmal atrioventricular block]

In thirty-one patients (pts) with atrioventricular or intraventricular conduction disturbances, the Ajmaline test was used to evaluate the risk of evolution to complete atrioventricular block. Three groups of patients were identified: A = nine patients without history of syncope or dizziness; B = seventeen pts with history of syncope or dizziness but without evidence of complete atrioventricular block; C = five pts with recorded atrioventricular block and history of syncope or dizziness. All patients with symptoms (B-C groups) and with a positive Ajmaline test (i.e. HV greater than or equal to 90 msec.) were paced with regression of symptoms. All patients without symptoms (A group) and with a positive Ajmaline test (i.e. HV greater than or equal to 90 msec.) were not paced and did not progress to complete atrioventricular block in a follow-up period of two years. Our results confirm that the Ajmaline test is useful in demonstrating the cardiac origin of syncopal episodes, but an HV value of 90 msec, does not seem to be specific enough in identifying asymptomatic patients at risk of developing complete atrioventricular block.