title: Comparison of individual and combined effects of procainamide and amiodarone in patients with sustained ventricular tachyarrhythmias.
abstract: To compare the individual and combined electrophysiological effects of amiodarone and procainamide, 35 patients with sustained ventricular arrhythmias underwent programmed stimulation in the control state, after procainamide (mean concentration, 8.7 +/- 2.8 micrograms/ml), after 13 +/- 2 days of amiodarone (1,400 mg/day x 7 days, then 400 mg/day), and after amiodarone with procainamide (mean procainamide concentration, 7.8 +/- 2.2 micrograms/ml). Sustained ventricular tachycardia (VT) was inducible in all 35 patients during treatment with procainamide alone and with amiodarone alone. Procainamide and amiodarone similarly increased the VT cycle length (+68 vs. +61 msec), the corrected QT interval (+63 vs. +49 msec), and the ventricular effective refractory period measured at paced cycle lengths of 600-550 msec (+23 vs. +21 msec) and 400 msec (+25 vs. +23 msec). Procainamide had a more pronounced effect on QRS duration than amiodarone during sinus rhythm (+18 vs. +8 msec, p less than 0.01) and during paced cycle lengths of 600-550 msec (+32 vs. +23 msec, p less than 0.01) and 400 msec (+37 vs. +28 msec, p less than 0.1) but a similar effect on the QRS duration during VT (+32 vs. +29 msec). During combination therapy, VT initiation was prevented in only two (6%) patients. The combination therapy produced a greater increase (p less than 0.001) than individual therapy in all the electrophysiological intervals assessed, with the exception of the sinus cycle length. On each drug regimen, a cycle length-dependent increase (p less than 0.05) in paced QRS duration was noted (400 more than 600-550 msec).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Clinical Electrophysiologic Laboratory, Hospital of the University of Pennsylvania, Philadelphia 19104.
authors.forename: F E
authors.initials: FE
authors.lastname: Marchlinski
authors.forename: A E
authors.initials: AE
authors.lastname: Buxton
authors.forename: K E
authors.initials: KE
authors.lastname: Kindwall
authors.forename: J M
authors.initials: JM
authors.lastname: Miller
authors.forename: M E
authors.initials: ME
authors.lastname: Rosenthal
authors.forename: C D
authors.initials: CD
authors.lastname: Gottlieb
authors.forename: R B
authors.initials: RB
authors.lastname: Bloom
authors.forename: M E
authors.initials: ME
authors.lastname: Josephson
mesh_terms: D000328:Adult; D000368:Aged; D000638:Amiodarone / Q000627:therapeutic use*; D002304:Cardiac Pacing, Artificial; D004338:Drug Combinations; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011342:Procainamide / Q000627:therapeutic use*; D012032:Refractory Period, Electrophysiological; D013617:Tachycardia, Supraventricular / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology
chemical_list: D004338:Drug Combinations; D011342:Procainamide; D000638:Amiodarone