RT-136
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Effects of defibrillator paddle
position on technical efficacy and energy requirements of transthoracic electrical
cardioversion of atrial fibrillation
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Giovanni Luca Botto, Alessandro
Politi, Walter Bonini, Tiziana Broffoni, Roberto Bonatti, Giovanni Ferrari.
Department of Cardiology, S. Anna Hospital, Como, Italy
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Abstract
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Aims. To define the effect of
defibrillator paddle position (DPP) on technical success and DC-shock (DCS) energy
requirements of elective transthoracic electrical cardioversion (TEC) of atrial
fibrillation (AF).
Methods. We studied 240 patients (pts) (age 62 ± 10 years) with
stable AF randomly assigned to undergo TEC using antero-lateral (Gr. AL; n = 119) or
antero-posterior (Gr. AP; n = 121) DPP. A step-up protocol was used, delivering a 3 J/kg
body-weight (b-w) DCS, then a 4 J/kg b-w (max 360 J) DCS, and finally, if AF still
persisted, a second 4 J/kg b-w DCS using the opposite DPP.
Results. The two groups were comparable for the all evaluated
clinical variables. The cumulative percentage of pts successfully converted to SR was 60%
in Gr. AL and 66% in Gr. AP with low-energy DCS (p = ns), it rise to 77% in Gr. AL and to
88% in Gr. AP with high-energy DCS (p = 0.023). Twenty-eight pts in Gr. AL and 14 pts in
Gr. AP experienced DCS with the opposite paddle position: AF persisted in 9/28 pts in Gr.
AL and 8/14 pts in Gr. AP. The mean DCS energy requirements were lower for Gr. AP pts (386
± 196 J) than Gr. AL pts (443 ± 236 J), p = 0.043. Arrhythmia duration is the only
factor that affected success of TEC (successful, 223 pts, 78 ± 111 days; unsuccessful, 17
pts, 197 ± 236 days; p < 0.0001). The success rate is lower if AF persists > 6
months (24/32 pts, 75% vs 199/208 pts 96%; p = 0.0001).
Conclusion. Antero-posterior defibrillator paddle position is
superior to antero-lateral location regarding technical success of TEC of stable AF, and
permits lower DC-shock energy requirements. Arrhythmia duration is the only clinical
variable that can limit the restoration of SR.
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Key Words
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Atrial fibrillation - transthoracic electrical
cardioversion
defibrillator paddle position, DC-schock energy requirements, transthoracic impedance,
antero-posterior versus antero-lateral position, OA
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