Objective To investigate the effective dose and safety of adenosine triphosphate(ATP) in inducing dual atrioventricular nodal pathways(DAVNP)phenomenon.Methods The ATP(the initial dose was 0.15 mg/kg,incremented 0.10 mg/kg each time)was injected to 40 patients who had slow-fast atrioventricular nodal reentrant tachycardia(AVNRT)through a femoral vein until signs of DAVNP,second-or third-degrec atrioventricular block(AVB)appared.The surface and intracardiac electrocardiogram was recorded consecutively.Results Forty patients of the slow-fast AVNRT had AVB after injecting ATP (16.1±5.8)mg(9-22 mg),29 patients(72.5%,29/40)occurred DAVNP phenomenon,of which 11 (37.9%,11/29)revealed DAVNP phenomenon after injecting ATP 0.15 mg/kg.Seventeen patients had side-effects of dyspnea,dizziness,cough,cardiopalmus and so on,but these side-effects were generally minor,short duration.Forty patients had transient cardiac arrhythmia.Conclusions The incremental low-dose method in inducing DAVNP has higher positive rate.The side-effects of ATP are mostly light and short duration,and can not cause serious consequence.

ObjectiveThe procedure of peroral endoscopic myotomy (POEM) was practiced in porcine esophagus-stomach model and the efficacy and safety of POEM for patients with achalasia were evaluated.MethodsThe ex-vivo esophagus-stomach was obtained and the pylorus was closed by hemostatic forceps.The entrance of the esophagus was fixed to foamed plastics.To perform POEM,a submucosal tunnel was created,after which the circular muscle layer was dissected and the mucosal entry was finally closed with clips.After successful animal experiment,we performed POEM on 4 patients with achalasia.Results POEM was completed in 5 porcine training models,in which 2 procedures were successful without any complication,2 were complicated with perforation in muscularis propria layer and 1 with rupture in mucosal layer.POEM was successfully performed in 4 patients with achalasia,with a mean operation time of 110min.The mean length of the submucosal tunnel was 10.5cm ( ranging 8-11 cm) and the mean length of myotomy of circular muscle layer was 7 cm (ranging 5-8 cm).The resting pressure of lower esophageal sphincter (LES) decreased from 52.4 mm Hg before POEM to 19.9 mm Hg.Massive bleeding occurred at the gastroesophageal junction in the first case and perforation occurred in mucosal layer during endoscopic hemostasis.All patients were followed up for 1-4 months,and the symptom of dysphasia was relieved significantly.ConclusionThe ex-vivo esophagus-stomach model can be used as training model for procedure of POEM,enabling endoscopists with enough experience for its use in patients.POEM is an effective therapy for achalasia,while the long-term efficacy and managements for complications are still to be elucidated.