Indian heart journal
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Indian heart journal · Mar 1996
Comparative StudyComparison of electrophysiologic effects and efficacy of single-dose intravenous and long-term oral amiodarone therapy in patients with AV nodal reentrant tachycardia.
Electrophysiologic effects and the efficacy of single-dose intravenous (i.v.) amiodarone were compared with those of long-term oral therapy in 9 patients of AV nodal reentrant tachycardia (AVNRT) utilising slow pathway (SP) for anterograde and fast pathway (FP) for retrograde conduction. Electrophysiologic data were obtained by programmed electrical stimulation (PES) before, 15 to 30 minutes after i.v. amiodarone (5 mg/kg body-weight over 10 minutes) and a mean of 64.6 +/- 23.7 days after oral therapy, on a maintenance dose of 200 to 400 mg daily. There was no significant influence on the sinus cycle length and infranodal conduction (HV) by i.v. or oral amiodarone as compared to pre-drug values. ⋯ Oral therapy prevented recurrence and reinducibility by its predominant effect in prolonging refractoriness of the atrium and ventricle, and depressing conduction through the retrograde FP. It is concluded that i.v. amiodarone is an effective drug in acute termination of tachycardia mediated by AV nodal reentry and that long-term oral therapy is excellent in preventing recurrence and reinducibility of tachycardia. There are significant differences in the electrophysiologic properties and mechanism of action between the two forms, not influenced by the blood levels of amiodarone.