Electrophysiological Characteristics Of Cardiomyocytes From Rabbit Pulmonary Vein Sleeves

Objective: Applying intracellular recording mode of the standard microelectrode technique to study the electrophysiological characteristics of cardiomyocytes from rabbit pulmonary vein sleeves (PVC), and observe the electrical conduction between PVC and left atrial cardiomyocytes(LAC). To explore the mechanism of paroxysmal atrial fibrillation originated from the pulmonary vein (PV).Methods: Multiple cardiomyocyte preparations from PV and LA of 50 healthy adult rabbits were obtained. The standard intracellular microelectrode technique was applied to record action potential(AP) of PVC and LAC, and a comparison of action potential duration(APD20,APD50,APD90) between them was made, In addition , the transmission relationship between PVC and LAC was tested. Finally,2mmol/L Caesium chloride(CsCl) was added into the superfusate,to probe the incidence of early after depolarization(EAD) was observed in the two parts, separately.Results: The action potential duration (APD) at 20%,50% and 90% repolarization(APD20,APD50,APD90) of PVC were longer than those of LAC obviously(P<0.05).In most cases, the AP signals from PVC can be conducted freely to LAC; on the contrary, the conduction signals from LAC can seldom reach PVC; EAD was more easily induced in PVC than in LAC.Conclutions: The conduction of AP between PVC and LAC was unequal,which may be the basis of reentry formation. EAD could be induced easily in PVC, with treatment of Cesium chloride, a K+ channel blockers, Together with the long APD, it was suggested that EAD genesis in PVC might be one of the mechanism of atrial arrhythmia originated in that special sourse.