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Prospective Evaluation of the Effect of Biphasic Waveform Defibrillation on Ventricular Pacing Thresholds
Author(s) -
KUDENCHUK PETER J.,
POOLE JEANNE E.,
DOLACK G. LEE,
GLEVA MARYE J.,
ANDERSON JILL,
TROUTMAN CHARLES,
BARDY GUST H.
Publication year - 1997
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.1997.tb00816.x
Subject(s) - defibrillation , medicine , ventricular fibrillation , defibrillation threshold , cardiology , shock (circulatory) , ventricular pacing , waveform , pulse (music) , heart failure , voltage , electrical engineering , engineering
Effect of Defibrillation on Pacing Thresholds. Introduction : Significant increases in ventricular pacing threshold have been observed following monophasic waveform ventricular defibrillation shocks. High‐output pacing is recommended to ensure consistent capture, particularly in pacemaker‐dependent patients who are likely to be defibrillated. Whether biphasic waveform defibrillation compounds this problem is not known. The purpose of this prospective study was to examine serial changes in ventricular pacing thresholds following single, multiple, low‐ and high‐energy biphasic defibrillation sbocks from an implanted defibrillator. Methods and Results : Bipolar pacing thresholds before and after defibrillation, and the adequacy of pacing capture at three times preshock threshold in the immediate aftermath of ventricular defibrillation, were prospectively evaluated in 67 consecutively tested recipients of a biphasic implanted cardioverter defibrillator. Overall, serial pacing thresholds following successful defibrillation were completely unchanged after 141 of 177 (80%) ventricular fibrillation inductions. In no case did the threshold pulse width increment > 0.06 msec from its baseline value after shock, nor did pacing at a pulse width of three times preshock threshold from dedicated bipolar pacing electrodes fail to result in successful ventricular capture. Changes in threshold were not related to when measured from the time of shock, defibrillation energy, number of shocks, electrode system, chronicity of leads, shock orientation, or to clinical factors. Conclusions : No clinically important changes in pacing threshold were observed after biphasic waveform defibrillation. Bradycardia pacing at conventional pacemaker outputs of three times baseline pulse width threshold from bipolar electrodes dedicated exclusively to pacing or sensing (but not defibrillation) consistently allowed for an adequate safety margin following defibrillation.