Efficacy of transesophageal defibrillation in ventricular fibrillation of long duration

Introduction: 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.