title: Clinical efficacy of shock waveforms and lead configurations for defibrillation.
abstract: A randomized, prospective comparison of the defibrillation efficacy of various shock waveforms and nonthoracotomy lead configurations was performed in five distinct patient groups undergoing implantation of a cardioverter defibrillator. In the first group using a bidirectional lead configuration, there was no significant difference in the mean defibrillation threshold (DFT) between simultaneous and sequential monophasic shocks (17.8 +/- 5.8 joules versus 17.3 +/- 2.7 joules). In the second group using a bidirectional lead configuration, the mean DFT was 21.9 +/- 7.3 joules with monophasic shocks and 14.9 +/- 5.0 joules with biphasic shocks (p < 0.001). In the third group using a unidirectional lead configuration, the mean DFT was significantly higher (p < 0.001) with monophasic shocks (22.1 +/- 4.2 joules) compared with biphasic shocks (15.0 +/- 5.4 joules). In the fourth group, an intraindividual comparison with monophasic shock waveforms showed no significant differences in DFT using either a bidirectional (21.3 +/- 5.8 joules) or a unidirectional (21.7 +/- 2.6 joules) lead configuration. In the fifth group, a simplified unipolar transvenous defibrillation lead system ("active can") demonstrated significant lower DFTs (9.7 +/- 3.8 joules) compared with a standardized unidirectional lead configuration (18.0 +/- 6.8 joules). It is concluded that: (1) there seems to be no significant difference in the DFT between simultaneous and sequential monophasic shocks; (2) biphasic waveforms require significantly less energy for defibrillation than their corresponding monophasic waveforms; and (3) the unipolar single-electrode defibrillation system is easy to implant and provides DFTs at energies comparable with epicardial lead systems.
authors.affiliation: Department of Cardiology, University of Bonn, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Jung
authors.forename: M
authors.initials: M
authors.lastname: Manz
authors.forename: R
authors.initials: R
authors.lastname: Moosdorf
authors.forename: S
authors.initials: S
authors.lastname: Spehl
authors.forename: C
authors.initials: C
authors.lastname: Wolpert
authors.forename: T
authors.initials: T
authors.lastname: Korte
authors.forename: B
authors.initials: B
authors.lastname: Lüderitz
mesh_terms: D000293:Adolescent; D000328:Adult; D002675:Child, Preschool; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000379:methods*; D004567:Electrodes, Implanted; D004867:Equipment Design; D006801:Humans; D011446:Prospective Studies; D014693:Ventricular Fibrillation / Q000453:epidemiology / Q000628:therapy*