|
| HOME | SUBSCRIPTIONS | CURRENT ISSUE | PAST ISSUES | CARDIOSOURCE | SEARCH | HELP | FEEDBACK |
|
|
|
|||||||||
|
|||||||||||
|
J Am Coll Cardiol, 1997; 30:233-236 © 1997 by the American College of Cardiology Foundation |
Department of Medicine, Division of Cardiology, University of Maryland School of Medicine, Baltimore, USA. MGold@heart.ab.umd.edu
OBJECTIVES: The purpose of this study was to compare chronic changes in monophasic and biphasic defibrillation thresholds using a uniform transvenous lead system and testing protocol. BACKGROUND: Defibrillation thresholds increase over time in patients with nonthoracotomy lead systems. This increase can result in an inadequate chronic defibrillation safety margin and could limit the safety of smaller pulse generators, which have a reduced maximal output. However, previous studies of the temporal changes of defibrillation thresholds evaluated complex lead systems or monophasic shock waveforms, neither of which are used with current technology. METHODS: This study was a prospective, randomized assessment of the effects of shock waveforms on the changes of transvenous defibrillation thresholds over time. Paired monophasic and biphasic thresholds were measured both at implantation and at follow-up (250 +/- 105 days) in 24 consecutive patients who were not receiving antiarrhythmic drugs. The lead system was a dual-coil Endotak C lead, and reverse polarity shocks (distal coil = anode) were delivered. RESULTS: Monophasic defibrillation thresholds increased from (mean +/- SD) 13.7 +/- 6.0 J to 16.8 +/- 6.7 J (p = 0.02), whereas biphasic thresholds were unchanged (10.4 +/- 4.3 J to 10.2 +/- 4.8 J, p = 0.86) in the same patients. Shock impedance chronically increased (47.0 omega to 50.5 omega, p = 0.02) and was unaffected by waveform. CONCLUSIONS: These results indicate that biphasic shocks prevent the chronic increase in defibrillation thresholds with a transvenous lead system.
This article has been cited by other articles:
|
|
 |
|
  S. H. Hohnloser, P. Dorian, R. Roberts, M. Gent, C. W. Israel, E. Fain, J. Champagne, and S. J. Connolly Effect of Amiodarone and Sotalol on Ventricular Defibrillation Threshold: The Optimal Pharmacological Therapy in Cardioverter Defibrillator Patients (OPTIC) Trial Circulation, July 11, 2006; 114(2): 104 - 109. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. A.M.J. Theuns, T. Szili-Torok, and L. J. Jordaens Defibrillation efficacy testing: Long-term follow-up and mortality Europace, January 1, 2005; 7(6): 509 - 515. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. J. Rashba, M. R. Olsovsky, S. R. Shorofsky, M. M. Kirk, R. W. Peters, and M. R. Gold Temporal decline in defibrillation thresholds with an active pectoral lead system J. Am. Coll. Cardiol., October 1, 2001; 38(4): 1150 - 1155. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Ammer, G.u. Lehmann, A. Plewan, K. Puetter, and E. Alt Marked reduction in atrial defibrillation thresholds with repeated internal cardioversion J. Am. Coll. Cardiol., November 1, 1999; 34(5): 1569 - 1576. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. R. Gold, S. Higgins, R. Klein, F. R. Gilliam, H. Kopelman, S. Hessen, J. Payne, S. A. Strickberger, D. Breiter, and S. Hahn Efficacy and Temporal Stability of Reduced Safety Margins for Ventricular Defibrillation: Primary Results From the Low Energy Safety Study (LESS) Circulation, April 30, 2002; 105(17): 2043 - 2048. [Abstract] [Full Text] [PDF]
|
|
| HOME | SUBSCRIPTIONS | CURRENT ISSUE | PAST ISSUES | CARDIOSOURCE | SEARCH | HELP | FEEDBACK |
