title: Effectiveness and safety of internal rectilinear biphasic versus monophasic defibrillation in patients undergoing cardiac surgery.
abstract: BACKGROUND
  Recently it has been shown that biphasic external shocks are more effective in the treatment of ventricular fibrillation (VF) compared with monophasic external shocks in terms of number of defibrillation attempts and maximal energy used for termination of VF. Biphasic defibrillators apply different biphasic impulse forms, depending on technology. To the authors' knowledge, there are no existing data concerning the effects of rectilinear biphasic internal shocks in patients undergoing cardiac surgery. The purpose of this study was to compare monophasic with rectilinear biphasic internal shock waveforms for termination of VF in patients undergoing cardiac surgery.
  
  
  METHODS
  One hundred thirty-four patients scheduled for elective cardiac surgery were prospectively randomized either to monophasic (group A) or biphasic (group B) internal defibrillation. Defibrillation was started with 7 J and increased stepwise to 30 J in each group until successful termination of VF after aortic declamping. The number of defibrillations, as well as the cumulative and maximal energy for termination of VF, were determined. Preoperatively, intraoperatively, and postoperatively troponin T, total creatine phosphokinase (CPK), and CPK- MB isoenzymes were measured.
  
  
  RESULTS
  In 64 patients (47%) VF occurred. The groups consisted of 32 patients each. The number of defibrillations (1.3 +/- 0.6 v 1.9+/- 1.2; p = 0.013), maximal energy per patient (7.9 +/- 2.5 v 11.6 +/- 7.32; p = 0.006), and cumulative energy (10.1 +/-6.1 v 21.3 +/- 24.1; p = 0.016) for successful termination of VF were significantly reduced in group B. Troponin T, CPK, and CPK-MB did not differ between groups.
  
  
  CONCLUSIONS
  Results of this study indicate that rectilinear biphasic internal defibrillation is more effective in the treatment of VF during cardiac surgery than is monophasic defibrillation. However, no significant difference in myocardial damage could be detected between groups.
authors.affiliation: Department of Anesthesiology, Hannover Medical School, Hannover, Germany. Winterhalter.Michael@mh-hannover.de
authors.forename: Michael
authors.initials: M
authors.lastname: Winterhalter
authors.forename: Till
authors.initials: T
authors.lastname: Piepenbrock
authors.forename: Rainer G
authors.initials: RG
authors.lastname: Leyh
authors.forename: Clemens
authors.initials: C
authors.lastname: Gras
authors.forename: Janusz
authors.initials: J
authors.lastname: Zuk
authors.forename: Jörn
authors.initials: J
authors.lastname: Heine
authors.forename: Christian
authors.initials: C
authors.lastname: Hagl
authors.forename: Niels
authors.initials: N
authors.lastname: Rahe-Meyer
authors.forename: Hartmut
authors.initials: H
authors.lastname: Hecker
authors.forename: Siegfried
authors.initials: S
authors.lastname: Piepenbrock
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000628:therapy*; D015415:Biomarkers; D001784:Blood Gas Analysis; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D003402:Creatine Kinase / Q000097:blood; D004554:Electric Countershock / Q000009:adverse effects; D004562:Electrocardiography; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007431:Intraoperative Complications / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D011446:Prospective Studies; D020107:Troponin T / Q000097:blood
chemical_list: D015415:Biomarkers; D020107:Troponin T; D003402:Creatine Kinase