His ECG is shown again here. It demonstrates sinus rhythm with a normal PR interval and incomplete right bundle branch block. The QRS duration is 0.11 second and the terminal portion of the QRS complex is widened with an S wave in leads I, aVL and V6 and an R’ in aVR and V1. The combination of a systolic murmur and incomplete right bundle branch block should always suggest an atrial septal defect and that was the diagnosis in this patient. There was a large ostium secundum atrial septal defect with a 3:1 shunt. The pulmonary artery systolic pressure was 40 mm Hg but the pulmonary vascular resistance was normal.