Ectopic atrial rhythm after superior septal approach to the mitral valve - an often under-reported entity.

Abstract

Very few reports elaborate on the changes in P wave following superior septal approach to the mitral valve. We aimed to describe the changes in the P wave axis and other electrocardiographic changes following this approach among patients preoperatively in sinus rhythm. We did a retrospective review of medical records among all our patients undergoing superior septal approach for mitral valve surgery from September 2014 to September 2019. Electrocardiograms during hospital stay and until 6-month follow-up were analyzed. A deviation in P wave axis from the normal range of + 30 to + 60° was classified as ectopic atrial rhythm. In the study population of 47 patients (age 16-75years, 51.3 ± 13.6years; M:F ratio 3.7:1), who were in normal sinus rhythm preoperatively, 34 patients (72.3%) had a visible P wave on electrocardiogram (ECG) at discharge. Among them, the P wave axes of 17 patients (36.2%) were within normal range (normal sinus rhythm), whereas 17 patients (36.2%) had ectopic atrial rhythm at discharge. The most frequent abnormal P wave axis was between 0 and - 30° (12 patients). At 6months, 8 patients (17.0%) had a persistent ectopic atrial rhythm. These patients underwent a Holter test at 6months and were followed up for symptomatic bradycardia for 3years. None of the patients with ectopic atrial rhythm required pacemaker insertion. Persistence of ectopic atrial rhythm at 6months is common (17%) after superior septal approach. Documentation of P wave axis after this approach will help avoid missing it. These patients may be kept on follow-up to look for symptomatic bradycardia.