Right bundle branch block as a marker for interatrial septal abnormalities

Background: Interatrial septal anomalies, which include atrial septal defect, patent foramen ovale, and atrial septal aneurysm, are common disorders among adult patients. Early detection of interatrial septal anomalies is important in order to prevent haemodynamic consequences and/or thromboembolic events. Electrocardiogram offers some clues that should serve as hints for detection of interatrial abnormalities. The aim of our study was to analyse the interatrial septum by transoesophageal echocardiography in patients with electrocardiogram signs of right bundle branch block and in those without right bundle branch block. Methods and results: In a prospective study, 87 adult patients were included, that is, 41 with electrocardiogram signs of right bundle branch block forming the first group and 46 without right bundle branch block forming the second group. Interatrial septal anomalies were present in 80.5% of the patients with right bundle branch block, with patent foramen ovale (39.02%) being the most prevalent disorder, followed by atrial septal aneurysm (21.9%) and atrial septal defect (19.5%). Interatrial septal abnormalities were significantly more frequent in the first group compared with the second group (80.5% versus 6.5%, p value less than 0.001). Independently, patent foramen ovale was significantly more prevalent in patients with right bundle branch block (39.02% versus 4.3%, p value less than 0.001), as were atrial septal aneurysm (21.9% versus 2.2%, p value equal 0.01) and atrial septal defect (19.5% versus 0%, p value equal 0.004). Conclusions: Right bundle branch block should serve as a valuable indicator to motivate a detailed search for interatrial septal abnormalities.