[Predictive value of the ajmaline test for the diagnosis of distal paroxysmal atrioventricular block (author's transl)]. / Valeur prédictive du test à l'ajmaline dans le diagnostic des blocs auriculo-ventriculaires paroxystiques distaux.

ABSTRACT

An ajmaline test was conducted in 120 patients with a history of disorders of consciousness Adams-Stokes syndrome (n = 49), loss of consciousness (n = 42), or lipothymia (n = 29). Four types of response were observed after ajmaline VH less than 80 ms (n = 63); VH between 80 and 100 ms (n = 19); VH greater than 100 ms (n = 17); distal block (n = 21). One hundred and fifteen of these patients were followed-up for from three to six years (mean 56 months). Pacemakers had been fitted in 46 of them. Atrioventricular block was eventually detected in 37 patients but was excluded in the other 78 cases, either because the syncope attacks did not recur or because another cause was demonstrated. The predictive value of the ajmaline test was confirmed by the subsequent course of the disorders. Based on only clinical findings, diagnosis was confirmed in 42 p. cent, excluded in 12 p. cent, and impossible to define in 46 p.cent of cases. After the ajmaline test, diagnosis was confirmed in 79 p.cent, excluded in 6 p.cent, and impossible to define in 15 p.cent. The risk of atrioventricular block can be evaluated as 1-6 p.cent when the increase in VH is less than 80 ms, 35.3 p.cent when the increase is between 80 and 100 ms, 62.5 p.cent when it is greater than 100 ms, and 100 p.cent when there is a distal block. The indications for fitting a pacemaker depend upon the results of this test. If contra-indications are respected (recent history of an infarct, cardiac failure, marked enlargement of the heart), complications are rare, being observed in less than 3 p.cent of cases.