Biphasic versus Monophasic Cardioversion in Shock.
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Cardioversion is the delivery of energy that is synchronized to the QRS complex, while defibrillation is asynchronous delivery of a shock randomly during the cardiac cycle. Early defibrillators delivered energy in a monophasic waveform, meaning that electrons flowed in a single direction.
Introduction. Atrial fibrillation (AF) is the most common cardiac arrhythmia and affects millions of people worldwide. 1 To reduce symptoms and prevent disease progression, direct current cardioversion is a widely used procedure for patients with AF. 2 During the past decades, biphasic waveforms have proven superior to monophasic waveforms for cardioversion of supraventricular tachycardia in.
A randomized controlled trial comparing safety and efficacy of rectilinear biphasic versus monophasic defibrillators in out-of-hospital cardiac arrest: ORBIT. Circulation 2003; 108:2I (abstract). Neal S, Ngarmukos T, Lessard D, et al. Comparison of the efficacy and safety of two biphasic defibrillator waveforms for the conversion of atrial fibrillation to sinus rhythm.
Direct current (DC) cardioversion or defibrillation can be delivered as monophasic or biphasic current. Monophasic current travels in one direction between the two electrodes. In biphasic devices, the current reverses direction part way through the shock waveform. The biphasic device requires lower energy and has been shown to lead to higher.
Biphasic versus monophasic shock waveform for conversion of atrial fibrillation. The results of an international randomized, double-blind multicenter trial. Page RL, Kerber RE, Russell JK, et al. American College Cardiology. shock, cardioversion was not achieved, a 5th crossover shock was delivered at the maximum energy of the alternate.
BACKGROUND: We compared efficacy of and pain felt after biphasic truncated exponential (BTE) and monophasic damped sine (MDS) shocks in patients undergoing external cardioversion of atrial fibrillation (AF). METHODS: Patients with AF were randomized to BTE or MDS waveform cardioversion. Successive shocks were delivered at 70, 100, 200, and 360 J until successful cardioversion, with one 360 J.
Simon J Walsh, Ben M Glover, AA Jennifer Adgey, “The Role of Biphasic Shocks 291 for Transthoracic Cardioversion of Atrial Fibrillation” groups.21 Two studies have suggested that the use of an AP configuration may be superior when monophasic waveforms are employed for DCC of AF.22,23 However, neither measured transthoracic impedance (TTI) with the varying electrode configurations.
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Comparison of rectilinear biphasic waveform energy versus truncated exponential biphasic waveform energy for transthoracic cardioversion of atrial fibrillation Author links open overlay panel Maureen L. Kim MD a Soo G. Kim MD b David S. Park MD c Jay N. Gross MD b Kevin J. Ferrick MD b Eugen C. Palma MD b John D. Fisher MD b.
Comparison of monophasic versus biphasic cardioversion for atrial fibrillation. Critical Care, Jun 2005 M Vaisman, MI Bittencourt, HCV Rey, FOD Rangel, RM Rocha, RC Costa Filho, LA Campos, FLB Gutierrez, AI Bronchtein, R Esporcatte.
Biphasic shocks deliver one cycle every 10 milliseconds and they are associated with fewer burns and less myocardial damage. With monophasic shocks, the rate of first shock success in cardiac arrests due to a shockable rhythm is only 60%, whereas with biphasic shocks, this increases to 90%(1). However, this efficacy of biphasic defibrillators.
Greene HL, DiMarco JP, Kudenchuk PJ et al. Comparison of monophasic and biphasic defibrillating pulse waveforms for transthoracic cardioversion. Am J Cardiology 1995;75(16):1135-39. Bardy GH, Marchlinski FE, Sharma AD et al. Multicenter comparison of truncated biphasic shocks and standard damped sine wave monophasic shocks for transthoracic ventricular defibrillation.
Interpretation: Compared to monophasic shocks, biphasic shocks allow the restoration of sinus rhythm with fewer shocks, less total energy, and with a lower risk of dermal injury. It is interesting to note that even in the biphasic group, cardioversion was ineffective in approximately 10% of patients.
Like monophasic devices, biphasic defibrillators can also be used for synchronized electrical cardioversion. Typically, biphasic defibrillation begins at 120 joules, with the level increased as needed. When used for synchronized electrical cardioversion, however, the device delivers a much lower energy level; for example, 30 joules.
The initial energy may be lower for cardioversion of atrial flutter (25). In a review including 985 cardioversions in 840 patients with atrial flutter, the median energy level for successful cardioversion was 50 joules with a biphasic defibrillator and 200 joules with a monophasic defibrillator (26).
Niebauer MJ, Brewer JE, Chung MK, Tchou PJ. Comparison of the rectilinear biphasic waveform with the monophasic damped sine waveform for external cardioversion of atrial fibrillation and flutter. Am J Cardiol 2004; 93:1495. Faddy SC, Jennings PA. Biphasic versus monophasic waveforms for transthoracic defibrillation in out-of-hospital cardiac.