Sinus node function after mitral valve surgery using the superior septal approach

Background. Sinus node function after the superior septal approach (SSA) in mitral valve surgery is controversial. We assessed sinus node function after this approach based on electrophysiological examinations and electrocardiographic change. Methods. Forty-six patients underwent successful mitral valve surgery via the SSA. Preoperatively, 25 patients were in atrial fibrillation (AF), 20 were in normal sinus rhythm (SR), and 1 patient was paced. Thirteen patients who demonstrated no sinus node dysfunction preoperatively underwent postoperative electrophysiological studies. Peripostoperative cardiac rhythm was monitored using a portable four-lead electrocardiograph, and late cardiac rhythm was examined using standard 12-lead electrocardiography in the outpatient clinic. Results. Twelve of 20 patients with preoperative SR experienced early postoperative supraventricular arrhythmias, but all spontaneously recovered SR. Electrophysiological studies revealed a basic cycle length of 767 ± 74 ms, sinoatrial conduction time of 72 ± 34 ms, sinus node recovery time of 1,119 ± 139 ms, and corrected sinus node recovery time of 349 ± 114 ms, thus demonstrating a lack of sinus node dysfunction. During the postoperative period (34 ± 24 months), 2 of the 20 patients with preoperative SR developed persistent AF, and 3 of the 25 patients with preoperative AF achieved normal SR. Conclusions. The SSA does not appear to cause long-term adverse effects on sinus node function, although temporary effects may occur.