Ventricular fibrillation induced by transoesophageal cardiac pacing: a new model of cardiac arrest in rats.
OBJECTIVE
To investigate whether transoesophageal cardiac pacing can induce ventricular fibrillation (VF) and how long the cardiac pacing has to be sustained to prevent the reversion of the VF induced.


METHODS
A pacing electrode was inserted orally into the oesophagus and high-frequency ventricular pacing was performed so as to elicit VF in 25 Sprague-Dawley rats. Incidences of VF and time of cardiac pacing were observed and recorded. Four minutes after onset of VF cardiopulmonary resuscitation (CPR) was initiated.


RESULTS
A short interval of high-frequency ventricular pacing caused an immediate drop of blood pressure, loss of pulse and increase of right atrial pressure in the same time frame. When the cardiac pacing was terminated, VF was elicited at least once or more than once in all of the 25 rats. However, the VF elicited by the burst stimulation could be defibrillated spontaneously. With the prolongation (120-180 s) of cardiac pacing, the incidence of defibrillation of VF decreased from 100 to 0%. VF persisted in 19 of 25 animals, developed into asystole in 5 of 25 animals and converted into pulseless electrical activity in 1 of 25 animals prior to CPR. Following CPR 22 of 25 animals were resuscitated.


CONCLUSIONS
Transoesophageal cardiac pacing can induce VF in rats. However, the cardiac pacing is required for at least 120-180 s to ensure that VF does not spontaneously convert. We can use the technique to establish a new and simpler rat cardiac arrest (CA) model, which may facilitate experimental investigation on CPR.
Chen
Meng-Hua
MH
Department of Physiology, School of Pre-Clinical Sciences, Guangxi Medical University, Nanning 530021, PR China.
Liu
Tang-Wei
TW
Xie
Lu
L
Song
Feng-Qing
FQ
He
Tao
T
Zeng
Zhi-Yu
ZY
Mo
Shu-Rong
SR
D000818:Animals; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects*; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D004195:Disease Models, Animal; D004562:Electrocardiography; D004947:Esophagus; D005260:Female; D006323:Heart Arrest / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000150:complications* / Q000503:physiopathology