Biphasic versus monophasic shock waveform for conversion of atrial fibrillation: the results of an international randomized, double-blind multicenter trial.
OBJECTIVE
This study compared a biphasic waveform with a conventional monophasic waveform for cardioversion of atrial fibrillation (AF).


BACKGROUND
Biphasic shock waveforms have been demonstrated to be superior to monophasic shocks for termination of ventricular fibrillation, but data regarding biphasic shocks for conversion of AF are still emerging.


METHODS
In an international, multicenter, randomized, double-blind clinical trial, we compared the effectiveness of damped sine wave monophasic versus impedance-compensated truncated exponential biphasic shocks for the cardioversion of AF. Patients received up to five shocks, as necessary for conversion: 100 J, 150 J, 200 J, a fourth shock at maximum output for the initial waveform (200 J biphasic, 360 J monophasic) and a final cross-over shock at maximum output of the alternate waveform.


RESULTS
Analysis included 107 monophasic and 96 biphasic patients. The success rate was higher for biphasic than for monophasic shocks at each of the three shared energy levels (100 J: 60% vs. 22%, p < 0.0001; 150 J: 77% vs. 44%, p < 0.0001; 200 J: 90% vs. 53%, p < 0.0001). Through four shocks, at a maximum of 200 J, biphasic performance was similar to monophasic performance at 360 J (91% vs. 85%, p = 0.29). Biphasic patients required fewer shocks (1.7 +/- 1.0 vs. 2.8 +/- 1.2, p < 0.0001) and lower total energy delivered (217 +/- 176 J vs. 548 +/- 331 J, p < 0.0001). The biphasic shock waveform was also associated with a lower frequency of dermal injury (17% vs. 41%, p < 0.0001).


CONCLUSIONS
For the cardioversion of AF, a biphasic shock waveform has greater efficacy, requires fewer shocks and lower delivered energy, and results in less dermal injury than a monophasic shock waveform.
Page
Richard L
RL
Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9047, USA. rpage@parknet.pmh.org
Kerber
Richard E
RE
Russell
James K
JK
Trouton
Tom
T
Waktare
Johan
J
Gallik
Donna
D
Olgin
Jeff E
JE
Ricard
Philippe
P
Dalzell
Gavin W
GW
Reddy
Ramakota
R
Lazzara
Ralph
R
Lee
Kerry
K
Carlson
Mark
M
Halperin
Blair
B
Bardy
Gust H
GH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000628:therapy*; D004311:Double-Blind Method; D004554:Electric Countershock / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome