Establishment Of Canine Model Of Spinal Cord Stimulation Atrial Fibrillation And Its Intervention

[Objective]To explore the establishment and intervention of canine model of Spinal cord stimulation atrial fibrillation,to provide a catrial omplete,scientific and feasible method for the scientific establishment of animal model of fibrillation,and to explore the efficacy of Spinal cord stimulation in the treatment of atrial fibrillation.[Methodology]Experimental dogs were randomly divided into 3 groups:(1)Control group(Ctrl group,n = 5);(2)Atrial fibrillation group(AF group,n=5)Implantation of atrial fibrillation model pacemaker was adjusted to AOO mode for high frequency pacing of right atrium.(3)Atrial fibrillation and Spinal cord stimulation group(AF and SCS group)Atrial fibrillation model pacemaker was adjusted to AOO mode for high-frequency pacing of right atrium and spinal cord stimulation electrode was implanted.AF group and AF +SCS group were implanted with tracker.The right lateral jugular vein was inserted into the right atrium in the right lateral jugular vein in group AF and group AF+SCS.After the test parameters were satisfactory,the connection pulse generator was buried subcutaneously in the neck,and the atrial fibrillation model was induced by the rapid pacing of the right atrium.The electrocardiogram was monitored once a week until P wave disappeared in the standard limb lead electrocardiogram.The atrial fibrillation wave F wave was replaced by the atrial fibrillation wave which was irregular in shape,interval and amplitude.The ventricular rhythm was definitely irregular and the atrial fibrillation model was established successfully.Spinal cord stimulation was performed in AF + SCS group for 2 months after successful modeling,the differences between AF group and AF+ SCS group in Ctrl group were obtained by comparing color Doppler echocardiography,anatomic heart observation and electrophysiological examination of left atrial myocytes,to investigate the effect of Spinal cord stimulation on atrial fibrillation.[Result]1.Establishment of canine atrial fibrillation model by implanting pacemakers through external jugular vein into right atrium during high frequency pacing,there was no atrial fibrillation in Ctrl group,atrial fibrillation models were established successfully in AF group and AF+ SCS group,severe hematomas appeared in the experimental dogs with atrial fibrillation,and the hematomas were absorbed and disappeared after compression bandaging again.During the whole course of the experiment,3 dogs suffered sudden death without any premonition,the onset time of atrial fibrillation was 9.4 ±3.16 weeks.2.Atrial fibrillation(AF)is a paroxysmal atrial fibrillation(PAF)as indicated by Revel LINQ monitoring instrument after successful modeling of atrial fibrillation.3.Echocardiography was performed,the left atrial diameter in AF group was increased by 28.56 ±2.78mm vs 18.63 ± 1.60 mm than that in Ctrl group(P<0.05)and the diameter of right atrium in AF group was 27.66 ± 1.45mmm vs 17.92± 1.36mm(P<0.05)after the establishment of the atrial fibrillation model.After spinal cord regulation,the left atrial diameter in AF +SCS group was decreased by 22.18 ±2.53mm vs 28.56 ±2.78mm than that in AF group(P<0.05).The right atrial diameter in AF+ SCS group was 25.83 ± 1.39mm vs 27.66 ± 1.45 mm,p>0.05,compared with AF group.The diameter of left atrium in AF +SCS group was 22.18±2.53mm vs 18.63 ±1.60 mm P<0.05,which was significantly larger than that in Ctrl group(25.83 ±1.39mm vs 17.92 ±1.36 mm P<0.05).4.Compared with Ctrl group,the voltage of left atrium in AF group was decreased by 1.80 ±0.81mv vs 7.49 ± 1.53 MV(P<0.05).Compared with AF group,the voltage of left atrium in AF +SCS group increased by 4.97 ±0.08mv vs 1.80 ±0.81 MV(P<0.05).Compared with Ctrl group,left atrial voltage in AF +SCS group was decreased by 4.97 ±0.08mv vs 7.49 ±1.53 MV(P<0.05).5.HE staining section,light microscope,blank control group:atrial myocytes arranged regularly,with no interstitial hyperplasia,clear muscle nucleus.In simple atrial fibrillation group,atrial myocytes were significantly decreased,myocytes denatured and atrial myocytes arranged in disorder.AF+SCS group:compared with blank control group,interstitial cells loosened,myocyte degeneration and fibrosis were lighter than simple atrial fibrillation group.6.The ultrastructural changes of left atrial myocardium were observed under electron microscope.In blank control group,the arrangement of myofibrillar ganglion in atrial myocytes was orderly and the chromatin structure in nuclear membrane was normal.In simple atrial fibrillation group:the ultrastructure of left atrial myocytes was significantly abnormal,the degeneration of atrial myocytes,myocardial fibrosis,severe degeneration and even loss of myofibroganglion,serious pyknosis of nucleus and enlargement of endoplasmic reticulum,The muscle fibers are disordered.In AF+SCS group:there were abnormal ultrastructural changes in myocytes,but no serious changes in myofibrillation group,myofibrillar ganglion was relatively clear and arranged neatly,and some muscle nuclei showed pyknosis.[Conclusion]1.The canine atrial fibrillation model induced by high frequency pacing through external jugular vein implanted 3830 pacing electrodes and through L2-L3 implanted the spinal cord stimulation electrode to spinal cord stimulation is safe,feasible and efficient.2.Spinal cord stimulation can effectively inhibit atrial structural changes caused by atrial fibrillation.