The altered transient outward (I_(to1)) and ultra-rapid delayed rectifier (I_(Kur)) K~+ currents in right atrial myocytes of human atrial fibrillation / 中国病理生理杂志

ABSTRACT

AIM: To study and evaluate the changes of two main kinds of voltage-gated K+ currents in human atrial fibrillation (AF) and to discuss the role of these changes in the atrial electrical remodeling (AER) caused by AF. METHODS: Specimens of human atrial appendage were obtained from 36 RHD patients (18 with chronic AF and 18 without AF). Single atrial myocytes were acutely dissociated by tissue chunk enzymatic digestion. I_~to1 and I_~Kur in the two groups were measured respectively with the patch-clamp technique in a whole-cell configuration and the I-V curves were compared. RESULTS: I_~to1 and I_~Kur amplitudes in AF groups were significantly reduced and the current densities of both I_~to1 and I_~Kur in AF patients were lower than those in NAF patients. CONCLUSION: The reduction of I_~to1 and I_~Kur may be related to changes in atrial conduction, refractory period and may constitute two main parts of the major mechanisms in the AER of chronic AF. Whether exists a relation between changes of the above K+ currents and that of other ionic currents and the AF initiation and perpetuation deserves further investigation. [