To investigate the potential mechanisms of atrial fibrillation in heart failure,right atrial appendages were obtained from 18 patients with decreased left ventricular function and 18 matched controls with normal left ventricular function. All patients were in sinus rhythm. The mRNA expression of I_ to1(KV4.3α) was measured by reverse transcription-polymerase chain reaction and normalized to the mRNA level of glyceraldehydes-3-phosphate dehydrogenase. Results: Compared to the control, the mRNA level of I_ to...