Objective To explore the method of constructing canine chronic heart failure(CHF)model by ultrasound-guided pacemaker implantation.Methods Five healthy canines were randomly selected.Under the guidance of ultrasound,the human pacemaker electrode was implanted into the right ventricular apex through the external jugular vein.After connecting the human pacemaker,it was placed in the right neck pocket.The ventricular asynchronous pacing mode was used with a pacing frequency of 180 beats per minute for 3 days,followed by 220 beats per minute for 3 days and finally 250 beats per minute for 3 weeks,the output voltage was 4.0 V and the pulse width was 0.5 ms.The effectiveness of constructing a canine CHF model was assessed by the clinical manifestations,echocardiography results,plasma brain natriuretic peptide(BNP)levels,and cardiac morphological changes before and after pacing.Results After 4 weeks of right ventricular pacing,5 canines showed clinical manifestations such as loss of appetite,dyspnea and decreased activity.Echocardiography confirmed a decrease in left ventricular ejection fraction.The plasma BNP level was increased by ELISA.The results of pathological staining showed that collagen fibers were increased.Transmission electron microscopy results showed that myocardial myofibrils were broken,sarcomeres were damaged,Z-lines were disappeared,and mitochondria were dissolved and cracked.Conclusion The canine model of CHF established by ultrasound-guided external jugular vein implantation of a human pacemaker is easy to operate and has a high success rate.It is a safe and efficient method for constructing a CHF model.
维普
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