Efficacy of transesophageal defibrillation in ventricular fibrillation of long duration.
BACKGROUND
Increasing duration of ventricular fibrillation (VF) is associated with a higher risk of ineffective resuscitation. In addition, precountershock chest compression can influence defibrillation success. Transesophageal defibrillation may increase defibrillation success because of the proximity of the esophagus to the heart. We evaluated the efficacy of transesophageal defibrillation compared with standard transthoracic defibrillation after long episodes of VF.


METHODS
Defibrillation success after 10 minutes of untreated VF was evaluated in 12 sheep randomized into 2 groups: (group A) in 6 sheep, up to 3 transthoracic shocks were applied, followed by up to 3 transesophageal shocks (first shock: 150 J, second and third shocks: 200 J). (group B) In 6 sheep, 2 minutes of precountershock chest compression preceded the defibrillation shocks. Truncated biphasic shocks were delivered between a sternal and an apical patch electrode for transthoracic defibrillation and between an esophageal and a cutaneous patch electrode for transesophageal defibrillation.


RESULTS
In group A with no precountershock chest compression, external defibrillation failed despite shocks with maximum energy (200 J) in all 6 sheep. Transesophageal defibrillation was successful in 3 sheep (50%). In group B with precountershock chest compression, external defibrillation failed in all 6 sheep. Transesophageal defibrillation was successful with the first shock in all 6 sheep.


CONCLUSIONS
Transesophageal defibrillation may terminate VF of long duration that is refractory to standard defibrillation. Precountershock chest compression may increase transesophageal defibrillation success.
Mischke
Karl
K
Department of Cardiology, RWTH Aachen University, 52074 Aachen, Germany. kmischke@ukaachen.de
Schimpf
Thomas
T
Knackstedt
Christian
C
Eickholt
Christian
C
Hanrath
Peter
P
Kelm
Malte
M
Schauerte
Patrick
P
D000818:Animals; D004554:Electric Countershock / Q000295:instrumentation* / Q000379:methods*; D004566:Electrodes; D004867:Equipment Design; D004947:Esophagus; D005260:Female; D012756:Sheep; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000628:therapy*