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Influence of Polarity Reversal on de‐fibrillation Success with Biphasic Shocks and a Transvenous/Subcutaneous Defibrillator System in a Porcine Animal Model
Author(s) -
STELLBRINK CHRISTOPH,
SCHAUERTE PATRICK,
LOESER HOLGER,
ROSENBAUM CHRISTOPH,
KUCKERTZ EDITH,
VOGEL MARTINA,
MESSMER BRUNO J.,
HANRATH PETER,
SCHOENDUBE FRIEDRICH A.
Publication year - 1998
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1998.tb00215.x
Subject(s) - medicine , cardiology , ventricular fibrillation , fibrillation , polarity reversal , defibrillation , anode , pulse (music) , atrial fibrillation , electrode , voltage , chemistry , physics , quantum mechanics
Clinical studies show that polarity reversal affects de‐fibrillation success in transvenous monophasic defibrillators. Current devices use biphasic shocks for de‐fibrillation. We investigated in a porcine animal model whether polarity reversal influences de‐fibrillation success with biphasic shocks. In nine anesthetized, ventilated pigs, the de‐fibrillation efficacy of biphasic shocks (14.3 ms and 10.8 ms pulse duration) with “initial polarity” (IP, distal electrode = cathode) and “reversed polarity” (RP, distal electrode = anode) delivered via a transvenous/subcutaneous lead system was compared. Voltage and current of each defibrillating pulse were recorded on an oscilloscope and impedance calculated as voltage divided by current. Cumulative de‐fibrillation success was significantly higher for RP than for IP for both pulse durations (55% vs 44%, P = 0.019) for 14.3 ms (57% vs 45%, P < 0.05) and insignificantly higher for 10.8 ms (52% vs 42%, P = n.s.). Impedance was significantly lower with RP at the trailing edge of pulse 1 (IP: 44 ± 8.4 vs RP: 37 ± 9.3 with 14.3 ms, P < 0.001 and IP: 44 ± 6.2 vs RP: 41 ± 7.6 Ω with 10.8 ms, P < 0.001) and the leading edge of pulse 2 (IP: 37 ± 5 vs RP: 35 ± 4.2 Ω with 14.3 ms, P = 0.05 and IP: 37.5 ± 3.7 vs RP: 36 ± 5 Ω with 10.8 ms, P = 0.02). In conclusion, in this animal model, internal de‐fibrillation using the distal coil as anode results in higher de‐fibrillation efficacy than using the distal coil as cathode. Calculated impedances show different courses throughout the shock pulses suggesting differences in current flow during the shock.