Transesophageal Pacing Cardiac Induces Cardiac Arrest and Subsequent Brain Injury in Rats

Abstract

Abstract Background Cardiac Arrest (CA) is one of the leading causes of mortality worldwide. The present study aimed to establish a simple and stable rat model of CA induced by transesophageal cardiac pacing for the investigation of cerebral resuscitation. Materials and Methods A total of 26 healthy adult male Sprague-Dawley rats were randomly allocated into two groups: Sham-operated (n = 6) and experimental (n = 20) groups. High-frequency cardiac pacing (50 Hz, 2 ms and 30 V) was maintained for 3 min to induce CA. Providing CA was not achieved, an additional 2 min of pacing was performed 30 min later. After 4 min following the onset of CA, Cardiopulmonary Resuscitation (CPR) was initiated. Results CA was successfully induced in all 20 rats by this setting of high-frequency cardiac pacing. Among them, CA was induced in six rats after 2 min of pacing; the remaining 14 rats underwent CA after 3 min of pacing. When electrical stimulation was terminated the rate of Pulseless Electrical Activity (PEA) was 85% (17/20), the rate of Ventricular Fibrillation (VF) was 15% (3/20) and no asystole occurred. Of the 17 PEA rats, 16 were successfully resuscitated and the average duration of CPR was 106.75 ± 30.81 s. A total of three rats succumbed within 24 h, and one rat succumbed between 24 and 48 h following successful resuscitation; 12 rats survived to <72 h. In addition, three rats with VF were successfully resuscitated and the average duration of CPR was 264.33 ± 130.40 s; one rat succumbed between 24 and 48 h following successful resuscitation, and two rats survived to <72 h. The 72 h-survival rate was 74%. No notable injury the esophagus was observed in the rats. Compared with the Sham group, the neurological function of the CA group was significantly impaired (p < 0.05); cells in the hippocampal CA1 region of the CA group were significantly damaged (p < 0.05). Conclusion The model of CA induced by transesophageal cardiac pacing in the present study is easy and replicable. Therefore, this model may be used for experimental research into cerebral resuscitation.

Keywords

• Cardiac pacing
• cardiac arrest
• cardiopulmonary resuscitation
• brain injury