The new mechanisms of automaticity controlled by the calcium and membrane clocks in sinoatrial node are helpful to revealing the sinus arrhythmia, but the present calcium dynamic model is only on the single cell level. In the present study, a central and peripheral single cell model was developed, and by exponentially changing the cell membrane capacitance, size, conductance and gap junction from the center to the periphery, a two-dimensional inhomogeneous sinus and atrial model was created on the basis of the anatomical structure. Five-point difference and finite element methods were used to process the internal grids and the borders. Irregular borders were defined by creating segment trial functions. Quantitative experiments suggested the consistency of the central and peripheral action potentials with related reports in amplitude, cycle length, maximum diastolic potential and upstroke velocity. Functions of the calcium and membrane clocks on the leading pacemaker site and upstroke velocity as well as the effects of the atrial premature beat on the sinus automaticity were also in good agreement with those in other studies. The developed model is helpful for deeply studying relative roles of the calcium and membrane clocks in automaticity and the relations with electrical activities in atrium. At the same time it will lay the foundation for building three-dimensional sinus and atrial organic models.
ObjectiveTo investigate the feasibility and clinical outcomes of bilateral endoscopic thoracic sympathectomy (ETS) through single hole for palmar hyperhidrosis (PHH). MethodsFrom August 2012 to April 2013, 19 PHH patients were admitted in the Department of Thoracic Surgery, The Third People's Hospital of Chengdu. There were 7 male and 12 female patients with their age of 24.7(15-33) years. All the patients underwent bilateral ETS through single hole under general anesthesia. ResultsAll the operations were successfully performed. Average operation time was 28.4 minutes, and postoperative hospital stay was 1.6 days. Seventeen patients were followed up for 2 to 10 months. PHH symptoms all disappeared without Horner's syndrome or hemopneumothorax. ConclusionBilateral ETS through single hole is a minimally invasive, reliable and safe procedure for PHH with low morbidity.