title: Clinical cardiac electrophysiologic evaluation of the positive inotropic agent, DPI 201-106.
abstract: DPI201-106 is a new positive inotropic agent. The cardiac electrophysiology of 16 patients was studied before and during DPI 201-106 administration (loading dose of intravenous DPI 201-106, 1.8 mg kg-1 h-1 administered over 10 min, followed by a maintenance dose of 0.2 mg kg-1 h-1). DPI 201-106 had no effect on the sinus node. The AH interval during fixed-rate atrial pacing became prolonged during DPI 201-106 infusion. There was a significant prolongation of the QT interval [QT (corrected), 417 +/- 22 to 502 +/- 35 ms, P less than 0.05; QT (atrial pacing at 600 ms), 374 +/- 17 to 419 +/- 23 ms, P less than 0.05; QT (ventricular pacing at 600 ms), 409 +/- 37 to 449 +/- 30 ms, P less than 0.05]. The ventricular effective refractory period significantly prolonged during DPI 201-106 administration (242 +/- 21 to 287 +/- 56 ms, P less than 0.05), but the supernormal-period duration decreased. The atrial effective refractory period was shortened in four patients and prolonged in one (261 +/- 67 to 240 +/- 53 ms, NS). The corrected atrial repolarization time (PTac) shortened significantly during DPI 210-106 infusion (479 +/- 26 to 445 +/- 22 ms at 20 min of the maintenance dose, P less than 0.05). Atrial fibrillation was initiated in five patients during DPI infusion, but no ventricular arrhythmia was provoked. These findings suggest that DPI 201-106 has novel differential electrophysiological effects on atria and ventricles.
authors.affiliation: Department of Cardiology, St Bartholomew's Hospital, London, U.K.
authors.forename: G S
authors.initials: GS
authors.lastname: Butrous
authors.forename: N M
authors.initials: NM
authors.lastname: Debbas
authors.forename: J
authors.initials: J
authors.lastname: Erwin
authors.forename: D W
authors.initials: DW
authors.lastname: Davies
authors.forename: H P
authors.initials: HP
authors.lastname: Keller
authors.forename: M W
authors.initials: MW
authors.lastname: Lunnon
authors.forename: A W
authors.initials: AW
authors.lastname: Nathan
authors.forename: A J
authors.initials: AJ
authors.lastname: Camm
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology; D006327:Heart Block / Q000503:physiopathology; D006329:Heart Conduction System / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects*; D010879:Piperazines / Q000097:blood / Q000494:pharmacology*; D012032:Refractory Period, Electrophysiological / Q000187:drug effects; D013268:Stimulation, Chemical
chemical_list: D010879:Piperazines; C046261:DPI 201-106