Waveform optimization for internal atrial defibrillation: effects of waveform rounding, phase duration, and voltage swing

BJ Kidwai, JD Allen, MT Harbinson, A McIntyre, JMCC Anderson, AAJ Adgey

    Research output: Contribution to journalArticlepeer-review

    8 Citations (Scopus)


    The aim of this study was to compare the efficacy of internal atrial defibrillation by conventional truncated exponential biphasic waveforms with and without waveform rounding (1-2 phases) and to determine optimal duration for this novel double rounded waveform. Atrial fibrillation, induced by rapid electrical stimulation, was converted by internal shocks through defibrillation catheters (lateral right atrium and coronary sinus) in anesthetised sheep. Rounding the leading edges of the conventional biphasic waveform (Ventritex HVS-02; settings 100/-50 V, 150/-70 V, and 200/-100 V; n = 8) reduced delivered peak and trough voltages, currents, and energy (by > or = 21 %, P < 0.001; for double (both phases) rounded) without decreasing cardioversion success. At 100/-50 V the efficacy of single (first phase) rounded (53 +/- 13%; mean +/- SEM) and double rounded (59 +/- 11%) shocks was similar to the conventional waveform (56 +/- 14%). Double rounded waveform (phase durations 1-20 ms) efficacy was optimum at 6-10 ms phase duration (100% success at 10-ms phase duration; 1.52 +/- 0.04 J delivered energy; n = 6). Successful cardioversion by conventional, single rounded, and double rounded biphasic waveforms (duration 6 ms each phase), conventional monophasic, rounded monophasic (duration 12 ms), and a damped sine waveform correlated strongly with peak-to-trough voltage swing within the waveform (r = 0.882; P < 0.01; n = 8). For internal atrial defibrillation, rounding both phases of the conventional biphasic waveforms, the double rounded waveform, permits similar efficacy to the conventional truncated exponential biphasic waveform at reduced peak voltage, current, and delivered energy. Optimum phase duration is 6-10 ms (tested range 1-20 ms).
    Original languageEnglish
    Pages (from-to)1198-1207
    JournalPacing and Clinical Electrophysiology : PACE
    Issue number8 Pt 1
    Publication statusPublished (in print/issue) - 2001

    Bibliographical note

    LR: 20061115RX: 850816 (on Jul 22, 2011)


    • Animals
    • Atrial Fibrillation: therapy
    • Catheterization: instrumentation
    • Defibrillators
    • Implantable
    • Disease Models
    • Animal
    • Electric Countershock: methods
    • Electric Stimulation
    • Electrodes
    • Sheep


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