title: Effect of verapamil on retrograde ventriculo-atrial conduction in children.
abstract: The effects of verapamil, a slow channel blocker and a potent antiarrhythmic drug, on retrograde V-A conduction were investigated following diagnostic cardiac catheterization in 12 children premedicated with lytic cocktail. Surface EKG, intra-atrial and His bundle electrograms, as well as right ventricular pacing with use of extra stimulus technique were obtained before and after a single intravenous dose of verapamil (0.15 mg/Kg, max 5 mg). Verapamil prolonged the AH interval in 9/12 and abolished or prolonged the retrograde V-A conduction whenever present (abolition in 5/12 and prolongation in 1/12). The duration of retrograde V-A conduction exceeded the antegrade conduction time in all. It is concluded that verapamil abolishes retrograde V-A conduction whenever present and this phenomenon may further explain the antiarrhythmic effects of the drug on retrograde conduction dependent (reentrant) arrhythmias.
mesh_terms: D000293:Adolescent; D001283:Atrioventricular Node / Q000187:drug effects; D002648:Child; D002675:Child, Preschool; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects* / Q000503:physiopathology; D006801:Humans; D008297:Male; D013997:Time Factors; D014700:Verapamil / Q000494:pharmacology*
chemical_list: D014700:Verapamil