RESUMO
<p><b>OBJECTIVE</b>To investigate changes in the expression of sarcoplamic reticular Ca(2+)-ATPase (SERCA) and IP(3)-I receptors (IP(3)R(1)) mRNA in patients with atrial fibrillation.</p><p><b>METHODS</b>Thirty-eight patients with mitral stenosis undergoing open heart surgery were studied. 100 mg of atrial tissue was obtained during surgery from the right appendage and the right atrium. The amount of messenger ribonucleic acid (mRNA) amount of SERCA and IP(3)R(1) was measured by reverse transcription-polymerase chain reaction (RT-PCR) and normalized to the mRNA levels of glyceraldehyde 3-phosphate dehydrogenase (GAPDH).</p><p><b>RESULTS</b>Levels of mRNA expression of SERCA in patients with AF, as compared with subjects in sinus rhythm, was lower and that of IP(3)R(1) was higher. The longer AF was sustained, the higher the levels of mRNA. There was no significant difference between right atrial free wall and right appendage.</p><p><b>CONCLUSIONS</b>The expression changes of SERCA and IP3R mRNA may correlate with the initiation or maintenance of AF.</p>