Sinus node function in patients operated for mitral valve disease. indirect evaluation with epimyocardial electrodes

To study the interatrial conduction times and atrial node performance in patients submitted to mitral valve surgery with the aid of temporary atrial epicardic electrodes. The atriograms were carried out in the first postoperative day and before the hospital discharge of ten consecutive patients. Sixty percent of the patients could complete the post-operative study protocol. The main results were: a) Post-operative arrhythmias were detected in 50% of the patients; b) There were no statistical differences between the pre and post-operative 12 lead EKGs. c) The interatrial conduction time (IACT) ranged from 90 to 140ms in the first post-operative day, and from 110 to 130ms at hospital discharge; d) The sinus node recovery time (SNRT) ranged from 250 to 560ms in the first post-operative day and from 180 to 360ms at hospital discharge; e) The sinus atrial conduction time (SACT) remained between 70 and 140ms, both in the first post-operative day and at hospital discharge, and; f) The IACT was normal in patients whose left atrium (LA) was less than 50mm in diameter but supra normal in the remaining cases. Sinus node function and inter-atrial conduction are not altered by mitral valve operation. Post-operative programmed epicardic atrial stimulation is easy and safe.