Beagle dog model and mongrel dog model of rapid right ventricle pacing induced-atrial fi brillation

Objective To select a more stable animal atrial fi brillation (AF) model by comparing the beagle dog and mongrel dog model of rapid right ventricle pacing-induced AF. Methods Eight mongrel dogs were divided into experimental group and control group (4 in each group), and 8 beagle dogs were divided into experimental group and control group (4 in each group). A pacing electrode was placed in the right cardiac apex of the animals in 2 experimental groups under X-ray guidance and connected to the pacer subcutaneously placed in the right neck. The animals were rapidly paced (240 times/min) and then sent back to their house, after two weeks their hemodynamic and electrophysiological indications were detected. The animals were then sacrificed with their heart removed and weighed. Results No significant difference was found in the heart rate, coefficient of heart and left ventricular end-diastolic pressure between beagle and mongrel dogs. No obvious variation was observed in the atrial refractory period between the 2 control groups. The atrial refractory period was shorter in beagle dogs than in mongrel dogs after pacing (P< 0.01) with no obvious reduction in experimental group of mongrel dogs. The incidence of AF in control group of beagle dogs was significantly different from that in control group of mongrel dogs. Conclusion The beagle dog model of rapid right ventricle pacing-induced AF is better than the mongrel dog model of rapid right ventricle pacing-induced AF.