Autonomic nervous system activation can result in significant changes of atrial electrophysiology and facilitate induction of atrial fibrillation. By recording influence of different concentrations of acetylcholine (ACh) on atrial fibers (AF), we investigated the role of the increased vagal tone in electrical remodeling in atrial fibrillation. Parameters of action potentials and force contraction (Fc) in atrial fibers were recorded by using standard intracellular microelectrode technique and force transducer. It was found that: (1) ACh at 0.1 μmol/L had no significant influence on spontaneous action potentials (SAPs) and Fc (n=6, P>0.05); ACh at both 1.0 and 10.0 μmol/L shortened action potential duration (APD) and Fc of human AF from right atrium (n=6, P<0.05); there was no significant difference in shortening APD between 10.0 and 1.0 μmol/L of ACh; (2) ACh at 0.1 μmol/L had no significant desensitization (n=6, P>0.05), but ACh at 1.0 and 10.0 μmol/L had desensitization (n=6, P<0.05) to SAPs and Fc. The desensitization of ACh on APD in AF was concentration- and time-dependent. It was shown that APD was longer than the control along with extending time of continuous Tyrode's solution perfusion after desensitization. It is concluded that ACh changes the electrophysiological characteristics of human AF, indicating that increased vagal tone plays a role in the development of a vulnerable substrate for atrial electrical remodeling in atrial fibrillation.

Objective To study the methodology and effect of auricle reconstruction with prefabricated expanded fascial flap in temporal and parietal area and skin flap in mastoid area, covered on the Medpor support. Methods Thirty cases of congenital vestigial auricle were involved in this study. The operations were divided into two stages: in the stage I,the temporal and parietal superficial fascia flap was cut with a vascular pedicle in the parietal and temporal superficial area, which was implanted under the skin of mastoid, and then both layers of those were expanded at the same time; in the stage II, this fascial skin flap was cut down and covered on the whole Medpor support to rebuild the man-made auricle. Results Thirty cases were successful after following-up for 6 months to 3 years. Their auricle shapes were vivid; their skin color was normal, and it had no any difference from all around skins, or no any appearance of the support. Conclusions With best understanding the biological characteristics of the Medpor support and choosing the suitable procedures and using the prefabricated expanded support, we could minimize the surgical complications in this operation. The results show that this procedure is satisfactory, without any necrosis of flap, swelling of contour, or appearance of the support. The combination of two flaps is the best method for the auricle reconstruction.

Autonomic nervous system activation can result in significant changes of atrial electrophysiology and facilitate induction of atrial fibrillation.By recording influence of different concentrations of acetylcholine (ACh) on atrial fibers (AF),we investigated the role of the increased vagal tone in electrical remodeling in atrial fibrillation.Parameters of action potentials and force contraction (Fc) in atrial fibers were recorded by using standard intracellular microelectrode technique and force transducer.It was found that:(1) ACh at 0.1 μmol/L had no significant influence on spontaneous action potentials (SAPs) and Fc (n=6,P＞0.05); ACh at both 1.0 and 10.0 μmol/L shortened action potential duration (APD) and Fc of human AF from right atrium (n=6,P＜0.05); there was no significant difference in shortening APD between 10.0 and 1.0 μmol/L of ACh; (2) ACh at 0.1 μmol/L had no significant desensitization (n=6,P＞0.05),but ACh at 1.0 and 10.0 μmol/L had desensitization (n=6,P＜0.05) to SAPs and Fc.The desensitization of ACh on APD in AF was concentration- and time-dependent.It was shown that APD was longer than the control along with extending time of continuous Tyrode's solution perfusion after desensitization.It is concluded that ACh changes the electrophysiological characteristics of human AF,indicating that increased vagal tone plays a role in the development of a vulnerable substrate for atrial electrical remodeling in atrial fibrillation.