In order to evaluate the clinical significance of the acid-base disturbance complicating hepatic encephalopathy, arterial blood gas and electrolyte levels were determined in 33 patients with encephalopathy due to various hepatic disorders. It was found the respiratory alkalosis occurred in 31 cases(93.9%) and respiratory acidosis complicated with metabolic acidosis in 2 cases (6.06%). In the 31 cases of respiratory alkalosis, there were 4 cases(12.12%) of simple respiratory alkalosis, 18 cases(54.55%) complicated with metabolic alkalosis, 3 cases(9.09%) complicated with metabolic acidosis, and 6 cases complicated with both metabolic alkalosis and acidosis. In addition, the arterial blood pH of 29 cases (87.87%) was above the normal value of 7.45. The main type of acid-base disturbance found in hepatic encephalopathy was alkalosis. Its occurrence was closely related to hypoxemia, hyperammonemia, and elevated blood level of progesterone in the case of respiratory alkalosis and to salt-limited diet and improper administration of diuretics and alkalite drugs in the case of metabolic alkalosis. Metabolic acidosis was usually the result of severe complitions. In alkalosis, there was frequently an elevation of blood free ammonia, which could penetrate the blood-brain barrier easily and induce coma and encephalopathy. Therefore energetic correction of alkalosis would be valuable to prevent hepatic encephalopathy. Effective treatment of the primary disease, correction of hyperventilation.correction of disturbances of blood electrolytes, and administration of arginine hydrochloride and potasium chloride would be appropriate measures in dealing with alkalosis.

OBJECTIVETo observe the changes of surface ECG and cell couplings between sinoatrial node cells and myocardial cells following transplantion of pedicled autologous sinoatrial node tissue graft into the right ventricle of a canine model of complete atrioventricular block.

METHODSTen healthy dogs were randomized into transplantation group and control group. Pedicled autologous sinoatrial node tissue grafts were transplanted into the right ventricle in the transplantation group, while the sinoatrial nodes were only excised in the control group after placement of temporary myocardial pacing wires. The changes of surface ECG were observed at 1, 2, 3 and 4 weeks postoperatively. At 4 weeks, complete atrioventricular block was induced in the dogs by radiofrequency ablation of the His bundle. The heart rate of the dogs in both groups were recorded after the injection of isoproternol (ISO) from the femoral vein, and the transplanted tissue graft was observed under optical and transmission electron microscopes.

RESULTSNo significant changes occurred in the surface ECG. All the dogs showed ECG waveforms specific of complete heart block after the ablation, and the ventricular heart rates were similar between the two groups (P>0.05). The ventricular heart rate did not undergo obvious changes after ISO injection (P>0.05). The transplanted pedicled autologous sinoatrial node survived in the dogs and the sinoatrial node cells established desmosome junctions with the myocardial cells, but the number of junctions was not sufficient to support heart pacing.

CONCLUSIONDesmosome junction can occur between ventricular myocardial cells and sinoatrial node cells at the edge of transplanted pedicled autologous sinoatrial node tissue.

Animals ; Atrioventricular Block ; physiopathology ; surgery ; Cardiotonic Agents ; pharmacology ; Dogs ; Electrocardiography ; Female ; Heart Rate ; drug effects ; Heart Ventricles ; surgery ; Intercellular Junctions ; Isoproterenol ; pharmacology ; Male ; Myocardium ; cytology ; Sinoatrial Node ; cytology ; transplantation ; Tissue Transplantation ; Transplantation, Autologous