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Post-shock myocardial stunning: A prospective randomised double-blind comparison of monophasic and biphasic waveforms

      Summary

      Introduction

      Compared with monophasic defibrillation, biphasic defibrillation is associated with less myocardial stunning and earlier activation of sodium channels. We therefore hypothesised that earlier sodium channel activation would result in earlier restoration of the first sinus beat following elective DC cardioversion.

      Methods

      Adults undergoing elective DC cardioversion were randomised to receive either monophasic or biphasic escalating transthoracic shocks. The ECG was recorded electronically during defibrillation and the time from delivery of the shock to restoration of the first sinus beat, measured from the beginning of the ‘P’ wave, was calculated.

      Results

      Seventy four patients were studied. Data were unavailable from 18 patients. There was no demographic difference between groups. Median time to the first sinus beat following monophasic defibrillation (n = 25) was 3.66 s (95% CI 2.55–4.61 s) and following biphasic defibrillation (n = 33) was 2.21 s (95% CI 1.76–2.56 s; P ≤ 0.0001). Linear regression confirmed that the waveform was an independent predictor of time to restoration of sinus rhythm; P < 0.0001. The final defibrillation energy level used to achieve cardioversion was not an independent predictor of time to restoration of sinus rhythm; P = 0.49.

      Conclusion

      Biphasic defibrillation for elective DC cardioversion achieved more rapid restoration of the first sinus beat compared with a monophasic waveform. Waveform, but not energy level that achieved defibrillation, was an independent predictor of time to restoration of the first sinus beat. The mechanism for this may be related to the earlier reactivation of sodium channels associated with the biphasic waveform.

      Keywords

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      References

        • Witkowski F.X.
        • Penkoke P.A.
        • Plonse R.
        Mechanism of cardiac defibrillation in open-chest dogs with unipolar DC coupled simultaneous activation and shock potential recordings.
        Circulation. 1990; 82: 244-260
        • Witkowski F.X.
        • Kerber R.E.
        Currently known mechanisms underlying direct current external and internal cardiac defibrillation.
        J Cardiovasc Electrophysiol. 1991; 2: 562-572
        • White R.D.
        Waveforms for defibrillation and cardioversion: recent experimental and clinical studies.
        Curr Opin Crit Care. 2004; 10: 202-207
        • Mittal S.
        • Ayati S.
        • Stein K.M.
        • et al.
        Comparison of a novel rectilinear biphasic waveform with a damped sine wave monophasic waveform for transthoracic ventricular defibrillation. ZOLL Investigators.
        J Am Coll Cardiol. 1999; 34: 1595-1601
        • DeBruin K.A.
        • Krassowska W.
        Electroporation and shock-induced transmembrane potential in a cardiac fiber during defibrillation strength shocks.
        Ann Biomed Eng. 1998; 26: 584-596
        • Jones J.L.
        • Jones R.E.
        • Balasky G.
        Microlesion formation in myocardial cells by high-intensity electric field stimulation.
        Am J Physiol. 1987; 235: H480-H486
        • Kodama I.
        • Shibata N.
        • Sakuma I.
        • et al.
        Aftereffects of high-intensity DC stimulation on the electromechanical performance of ventricular muscle.
        Am J Physiol. 1994; 267: H248-H258
        • Tang W.
        • Weil M.H.
        • Sun S.
        The effects of biphasic and conventional monophasic defibrillation on postresuscitation myocardial function.
        J Am Coll Cardiol. 1999; 34: 815-822
        • Reddy R.
        • Gleva M.
        • Gliner B.
        • et al.
        Biphasic transthoracic defibrillation causes fewer ECG ST-segment changes after shock.
        Ann Emerg Med. 1997; 30: 127-134
        • Kodama I.
        • Sakuma I.
        • Shibata N.
        • Honjo H.
        • Toyama J.
        Arrhythmogenic changes in action potential configuration in the ventricle induced by DC shocks.
        J Electrocardiol. 1999; 32: 92-99
        • Jones J.L.
        • Jones R.E.
        Decreased defibrillator-induced dysfunction with biphasic rectangular waveforms.
        Am J Physiol. 1984; 247: H792-H796
        • Roth B.J.
        Mechanisms for electrical stimulation of excitable tissue.
        Crit Rev Biomed Eng. 1994; 22: 253-305
        • Jones J.L.
        • Jones R.E.
        • Milne K.B.
        Refractory period prolongation by biphasic defibrillator waveforms is associated with enhanced sodium current in a computer model of the ventricular action potential.
        IEEE Trans Biomed Eng. 1994; 41: 60-68
        • Keener J.P.
        • Lewis T.J.
        The biphasic mystery: why a biphasic shock is more effective than a monophasic shock for defibrillation.
        J Theor Biol. 1999; 200: 1-17
        • Blanchard S.M.
        • Ideker R.E.
        Mechanisms of electrical defibrillation: impact of new experimental defibrillator waveforms.
        Am Heart J. 1994; 127: 970-977
        • Jones J.L.
        • Tovar O.H.
        Electrophysiology of ventricular fibrillation and defibrillation.
        Crit Care Med. 2000; 28: N219-N221
      1. Part 4: the automated external defibrillator: key link in the chain of survival. European Resuscitation Council. Resuscitation 2000; 46: 73–91.

        • Altman D.G.
        How large a sample?.
        in: Gore S.M. Altman DG. Statistics in practice. British Medical Association, London1982: 6-8
        • Jones J.L.
        • Jones R.E.
        Improved defibrillator waveform safety factor with biphasic waveforms.
        Am J Physiol. 1983; 245: H60-H65
        • Chun P.K.
        • Davia C.J.
        • Donohue D.J.
        ST-segment elevation with elective DC cardioversion.
        Circulation. 1981; 63: 220-224
        • Tang W.
        • Weil M.H.
        • Sun S.
        • et al.
        A comparison of biphasic and monophasic waveform defibrillation after prolonged ventricular fibrillation.
        Chest. 2001; 120: 948-954
        • Tang W.
        • Weil M.H.
        • Sun S.
        Low-energy biphasic waveform defibrillation reduces the severity of postresuscitation myocardial dysfunction.
        Crit Care Med. 2000; 28: N222-N224
        • Tang W.
        • Weil M.H.
        • Sun S.
        • et al.
        The effects of biphasic waveform design on post-resuscitation myocardial function.
        J Am Coll Cardiol. 2004; 43: 1228-1235