Superior septal approach for mitral valve surgery: a word of caution

Abstract

Objective: Superior septal approach provides excellent exposure of the mitral valve and the subvalvular structures. The unavoidable section of the sinus node artery is in relationship with this technique. We have studied the electrical changes associated after using this approach.

Material and methods: We studied 247 cases of mitral valve surgery from 1996 to 2003. The patient population was divided into two comparative groups: group I (128 cases) was represented by the superior septal approach and group II (119 cases) composed the conventional right lateral approach through the left atrium. Preoperatively, 48 patients (37.5%) in group I and 46 (38.6%) in group II were in a normal sinus rhythm. Mean follow-up was 30.7 months in group I and 33.5 months in group II.

Results: There was no mortality in group I and eight cases (6.7%) in group II. A high incidence of changes as junctional rhythm was observed in group I, especially after weaning of cardiopulmonary bypass and on the first day after surgery (P>0.001). Postoperative P-R interval of the patients in sinus rhythm was 100+/-30 ms in group I and 148+/-24 ms in group II (P>0.05). P-R interval in group I was shorter than normal. P-wave morphology changed becoming inverted in leads II, III and aVF after surgery in these cases in group I. A full recuperation in P-R interval and the P-wave axis was seen in 52 cases (87.5%) in patients in group I after the third postoperative month. A definitive pacemaker implantation was need in two cases (1.5%) in group I and in six (5%) in group II (P>0.05).

Conclusions: A superior septal approach is directly related with the loss of normal sinus rhythm because of the section of the sinus node artery. After a brief period of transient electrical changes, a new low atrial or coronary sinus rhythm slower than normal sinus rhythm appears. In consequence, a word of caution must be strongly considered in patients critically dependent on normal sinus rhythm, despite the low incidence of definitive electrical changes. Normal sinus rhythm appears again after the third postoperative month.