[Arrhythmogenic effect of ajmaline on the atrial level].
Ključne besede
Povzetek
The aim of this study was to determine whether an antiarrhythmic, Ajmaline, could have proarrhythmic effects on the atrium and to compare the results with those of other antiarrhythmic drugs. A total of 1950 patients without cardiac failure or recent (less than 6 weeks) myocardial infarction were given 1 mg/kg of Ajmaline intravenously during electrophysiological investigation. A proarrhythmic effect was defined as the occurrence of supraventricular tachycardia (SVT) in a patient without this arrhythmia before the test or the facilitation of its induction. Fifty five patients developed SVT (mainly atrial tachyarrhythmias: 48 cases, and some junctional tachycardia: 7 cases) which occurred spontaneously in 22 patients and during fixed atrial pacing in 33 patients. Fifteen patients developed ventricular tachycardia (VT). The predisposing factors for the development of SVT were: a previous history suggesting spontaneous SVT (28 patients; 51 p. 100); sinoatrial block (14 patients--the only abnormality in 10 cases). Seventeen patients had none of these factors but 8 had known cardiac pathology and the other 9 were relatively elderly patients (79 years). Twelve of the patients developing VT had known cardiac disease, bundle branch block in 12 cases and previous VT in 6 cases. In conclusion, proarrhythmic effects of Ajmaline are infrequent if its contraindications are respected, but they do exist at both atrial (2.8 p. 100) and ventricular levels (0.8 p. 100): the risk factors are comparable: previous spontaneous arrhythmias or ECG changes (SA block at the atrial and bundle branch block at the ventricular level).