Electrocardiogram changes during the induction of ventricular fibrillation and resuscitation in a rabbit cardiac arrest model induced by esophageal electrodes

Background: Although the ventricular fibrillation (VF) cardiac arrest (CA, VFCA) rabbit model is very widely used, research on electrocardiogram (ECG) changes during the establishment of the VFCA model remains scarce. This study aimed to explore the impact of stimulation time and pattern on VF occurrence during the VFCA rabbit model establishment and to examine ECG characteristics alongside real-time dynamic blood pressure (BP) throughout the stimulation and resuscitation phases. Methods: VFCA was induced in male New Zealand rabbits using a transesophageal-chest wall electrode with 50 V 30 Hz alternating current. Rabbits were subjected to electrical stimulation for durations of 30 s, 45 s or 60 s. If initial stimulation failed to induce 3-min CA, rabbits were reassigned to either intermittent or continuous stimulation until a 3-min CA was achieved. Results: The study conducted 88 electrical stimulations on 42 male New Zealand rabbits to induce 3-min CA, with 32 rabbits (76.2%) requiring one or two stimulations to achieve this. Of the 88 stimulations, 77 (87.5%) successfully induced CA, including 73 (83.0%) cases of VF. An analysis of 42 initial stimulations revealed 35 VFs, with 13 instances leading to a 3-min CA. The 30 s and above-30 s of stimulation time groups exhibited 8 and 27 VF occurrences (χ2 = 1.890, p = 0.169) and 2 and 11 3-min CA events (χ2 = 0.805, p = 0.370), respectively. Except for the initial stimulation, 46 stimulations were given, including 20 intermittent stimulations and 26 continuous stimulations, which resulted in 17 and 21 VFs (χ2 = 0.000, p = 1.000) and 13 and 16 3-min CA events (χ2 = 0.058, p = 0.809), respectively. In addition, a significant difference in stimulation time was observed between the intermittent and continuous stimulation groups. Conclusions: Our results provide important insights that could be used to improve the success rate of establishing VFCA rabbit models.

Ventricular fibrillation; Cardiac arrest; Esophageal-chest; Electrocardiogram; Rabbits

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