Potential benefit of transesophageal defibrillation: an experimental evaluation.
BACKGROUND
Because of the proximity of the esophagus to the heart, transesophageal defibrillation might increase defibrillation success. We assessed the defibrillation threshold (DFT) of transesophageal defibrillation compared with standard transthoracic defibrillation.


METHODS
Defibrillation success and DFTs were determined in 22 female pigs with high (68+/-4 kg, n=12) or low body weight (39+/-1 kg, n=10). After induction of ventricular fibrillation, biphasic shocks were delivered between two cutaneous patch electrodes (sternal and apical position) or between an esophageal and two cutaneous patch electrodes in a sternal and apical position. The esophageal electrode was integrated into a latex sheath covering a standard transesophageal echocardiography probe.


RESULTS
In 5 of 12 pigs with high body weight, external defibrillation failed despite 3 consecutive 200-J shocks, whereas subsequent transesophageal defibrillation was successful with the first shock. In the remaining 7 pigs, a more than 50% reduction in DFT was obtained with transesophageal defibrillation compared with standard biphasic external defibrillation (67+/-27 vs 164+/-23 J, P<.001). Pigs with lower body weight were successfully defibrillated by both transthoracic and transesophageal shocks. The DFT in pigs with low body weight was significantly lower using transesophageal defibrillation compared with transthoracic shocks (65+/-15 vs 99+/-38 J, P<.05).


CONCLUSIONS
In this animal model, nonresponders to standard external defibrillation could successfully be defibrillated via an esophageal-cutaneous electrode configuration. Overall, an almost 50% DFT reduction was achieved by transesophageal defibrillation. Transesophageal defibrillation may provide an additional tool for terminating VF, which is refractory to external defibrillation, eg, in patients with very high body weight.
Mischke
Karl
K
Department of Cardiology, RWTH Aachen University, 52074 Aachen, Germany. kmischke@ukaachen.de
Schimpf
Thomas
T
Knackstedt
Christian
C
Zarse
Markus
M
Eickholt
Christian
C
Plisiene
Jurgita
J
Frechen
Dirk
D
Gramley
Felix
F
Schauerte
Patrick
P
D000818:Animals; D001835:Body Weight; D004195:Disease Models, Animal; D004554:Electric Countershock / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004947:Esophagus; D005260:Female; D013552:Swine; D014693:Ventricular Fibrillation / Q000628:therapy*