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Evaluates the effect of falipamil on persistent atrial fibrillation induced by atrial pacing. Administration of the drug by slow intravenous injection; Similarity of the atrial anti-arrhythmic properties of falipamil to those of Class IA anti-arrhythmic agents; Justification of pacing-induced atrial fibrillation either because of the presence of documented atrial fibrillation or flutter or because of the possible involvement of the arrhythmia in the symptoms.

The article presents information on a study regarding the effects of a single intravenous injection of flecainide on acute episodes of supraventricular tachyarrhythmias. For this study, thirty patients were studied. Flecainide is a newly introduced antiarrhythmic agent. There are reports on its efficacy in the prevention of supraventricular and ventricular arrhythmias. The authors noted effects of flecainide on anterograde conduction through the atrioventricular node and retrograde conduction through accessory pathways, confirming multiple sites of action of flecainide in reentrant arrhythmias.

The electrocardiographic characteristics of spontaneous escape rhythm during complete heart block induced by transcatheter ablation of the atrioventricular junction was prospectively studied in 21 patients by periodically interrupting temporary pacing. The data derived from 13 of these 21 patients, in whom conduction recurred after the procedure, were analyzed. An escape rhythm was present In 12 patients 8.2 ± 5.8 minutes after shock delivery at a cycle length of 1985 ± 974 ms. The escape QRS had a configuration of right bundle branch block with left axis deviation in 9 patients, of right bundle branch block with normal axis in 1, of left bundle branch block with left axis deviation in 1, and 2 distinct morphologies in the remaining patient. After resumption of conduction, the conducted complexes were identical to the escape complexes in six patients, different only in axis in four patients, and different in morphology in two patients. This suggests that in the majority of patients the escape rhythm seen during transient heart block, induced by transcatheter ablation of the atrioventricular junction, presents a right bundle branch morphology with or without a left axis deviation, and most likely originates from an area above, or close to, the site of the anatomical damage. [ABSTRACT FROM AUTHOR]

We report on two patients out of a series of 22 who underwent transcatheter ablation of the atrioventricular (AV) junction. The procedure failed to induce permanent complete heart block in 15 patients, 12 of whom were in sinus rhythm with 1:1 AV conduction before hospital discharge. Of the 12 patients, two (16.6%) were found to be in high degree heart block, one month later. We discuss the mechanism of late occurrence of high degree heart block and we emphasize the need for systematic implantation of permanent ventricular or dual chamber pacemakers, despite failure transcatheter ablation of the AV junction. [ABSTRACT FROM AUTHOR]

Although pacing-induced ventriculo-atrial (VA) Wenckebach conduction has been previously described, the occurrence of this phenomenon during ventricular tachycardia has received little attention. The latter is defined as 2:2 VA block in which the conducted beats show progressive lengthening of VA conduction until the sequence is terminated by two or three blocked ventricular beats. This phenomenon was observed in a 16-year-old boy who underwent electrophysiologic study for ventricular tachycardia as a late complication of surgical correction of tetralogy of Fallot. During pacing-induced ventricular tachycardia with a morphology similar to that of the spontaneous tachycardia, 8:4 alternating VA block was observed. This sequence suggested that the AV node was the site of block, the 2:2 block being located at the upper level, and the VA Wenckebach block at the lower level. Alternate VA Wenckeboch conduction appears as a possible cause of variation in atrial depolarization intervals during ventricular tachycardias with short cycle lengths. [ABSTRACT FROM AUTHOR]

Evaluates the effect of hydroquinidine in patients with inducible ventricular tachycardias using programmed electrical stimulation. Relation of arrhythmia with coronary artery disease in patients; Method used for selection of the appropriate antiarrhythmic agent; Information on spontaneous sustained ventricular tachycardias.

The electrophysiological properties of falipamil (AQA-39), a new antiarrhythmic agent with bradycardic effect, were evaluated in 12 patients. Intravenous falipamil (1.5 mg/kg within 20 minutes) significantly prolonged sinus cycle length (control, 862 ± 148 msec; Falipamil, 941 ± 170 msec). The PR interval was significantly shorter due to AH interval shortening (P < 0.004). The antegrade Wenckebach point occurred at a higher rate. These findings were ascribed to an anticholinergic effect. The major electrophysiological findings included significant prolongation of the refractory periods of atrium and ventricle, whereas those of the AV node were not affected. Retrograde ventriculoatrial conduction present in 8 patients was not altered. In conclusion falipamil prolongs sinus cycle length and depresses atrial and ventricular functions, which is suggestive of antiarrhythmic properties at the atrial and ventricular levels. [ABSTRACT FROM AUTHOR]