[Cibenzoline: electrophysiologic effects of a new class I anti-arrhythmia agents in supraventricular tachycardia].

Cibenzoline, an imidazoline derivate, is a new class 1 antiarrhythmic agent. The electrophysiologic effects and antiarrhythmic properties of cibenzoline (100 mg i.v.) were evaluated in 22 patients with paroxysmal supraventricular tachycardia: 12x Wolff-Parkinson-White Syndrome, 9x AV nodal reentrant tachycardia, 1x atrial tachycardia. Cibenzoline shortened the sinus cycle length from 742 +/- 103 ms to 661 +/- 87 ms (p less than 0.001) and the sinus node recovery time from 1026 +/- 106 ms to 926 +/- 135 ms (p less than 0.001). The substance lengthened the AH interval from 93 +/- 19 ms to 112 +/- 24 ms (p less than 0.001) and the HV interval from 42 +/- 12 ms to 61 +/- 14 ms (p less than 0.001). The effective refractory periods of the atrium and right ventricle did not change significantly, but the effective refractory period of the AV node in antegrade (269 +/- 42 ms vs 278 +/- 46 ms; p less than 0.05) and retrograde direction (281 +/- 57 ms vs 413 +/- 124 ms; p less than 0.001) increased markedly. Cibenzoline prolonged the effective refractory period of the accessory pathway in retrograde direction from 263 +/- 41 ms to 428 +/- 101 ms (p less than 0.001). The effective refractory period of the antegrade accessory pathway did not change. During atrial stimulation inducibility of the reentrant tachycardia was suppressed in 14 of 22 patients and the inducibility of atrial fibrillation in 7 of 12 patients. The RR interval of the reentrant tachycardia was prolonged from 353 +/- 57 ms to 420 +/- 57 ms (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)