Fifty-eight patients with isolated aortic stenosis who underwent open heart surgery during a three-year period had a 49% incidence of postoperative supraventricular arrhythmias (SVAs). Of the 22 patients under 20 years of age (group A), four (18%) had postoperative SVAs, in contrast to 24 of the 36 patients (66.7%) over 40 years of age (group B). The increase in SVAs in group B was due to increased frequency of atrial flutter-fibrillation. The electrophysiologic characteristics of the right atrial myocardium were normal in group A, but were markedly abnormal in group B. The diffuse spontaneous phase-4 depolarization, local conduction disturbances, and abnormal transmembrane action potential characteristics found in group B could result in multifocal ectopic pacemakers and reentry arrhythmias. Therefore, the majority of the postoperative SVAs in group B may be related to the preoperative cellular abnormalities of their right atrial myocardium.
Bush HL, Gelband H, Hoffman BF, Malm JR. Electrophysiological Basis for Supraventricular ArrhythmiasFollowing Surgical Procedures for Aortic Stenosis. Arch Surg. 1971;103(5):620-625. doi:10.1001/archsurg.1971.01350110122020