title: Ventricular Wenckebach after intravenous therapy with class I antiarrhythmic agents.
abstract: Two unusual cases of Wenckebach-like conduction block in the infranodal tissues which developed after an intravenous dose of a Class I antiarrhythmic drug are presented. The first case shows infra-Hisian Wenckebach during sustained atrioventricular nodal reentrant tachycardia. The second case demonstrates rate-dependent Wenckebach-like exit block between the pacing catheter and the right ventricular tissues during pacing.
mesh_terms: D000328:Adult; D002304:Cardiac Pacing, Artificial; D004206:Disopyramide / Q000008:administration & dosage / Q000009:adverse effects*; D004594:Electrophysiology; D005260:Female; D005424:Flecainide / Q000008:administration & dosage / Q000009:adverse effects*; D006327:Heart Block / Q000139:chemically induced* / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013617:Tachycardia, Supraventricular / Q000175:diagnosis
chemical_list: D004206:Disopyramide; D005424:Flecainide