| Background and objectivesAtrial fibrillation (AF) is the most common arrhythmia in clinical practice. It is evident that with population aging, AF has become an important issue of public health. Rapid atrial excitement may cause electrophysiological alterations and promote the occurrence and maintenance of AF. The process called"atrial remodeling in AF"firstly described by Wijffels et al in 1995, which shedded lights on the mechanism of AF. During atrial electrophysiological remodeling, the properties and distribution of cardiac ionic channels such as potassium channels and calcium channels (particularly L-type voltage dependent calcium channel (LVDCC)) might be the initiators, which alter the electrical activities of the atrium and promote the occurrence and maintenance of AF, but the mechanism of cellular and molecular electrophysiology of atrial electrical remodeling is still unclear. Intracellular calcium overload is considered as the predominating factor for atrial electrical remodeling; however, relevant evidence was indirect. Therefore, further studies are required to confirm the influence of rapid atrial pacing on calcium ion channels and to provide rationale for improving the therapeutic strategy for AF.Methods1) Experimental model of rapid atrial pacing in rabbits was established, and electrodes were inserted into the right atrium via the right external jugular vein. Pacing was performed using a continuous single-stimulus modality, with a frequency of 600 stimuli per min, a cycle of 0.5ms, and a voltage of 3.7V. Histomorphology and ultramicrostructure were observed.2) Adult rabbits, weighting 2.6 to 4.2 kg, were randomized to 6 groups according to the...
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