[Electrocardiographic observations of pure septal infarction: a case report]

We report a very rare case of pure septal infarction, which was closely examined with detailed electrocardiography (ECG). The patient is a 65-year-old man, who underwent percutaneous transluminal coronary angioplasty (PTCA) for exercise-induced angina. During PTCA for the target lesions in the left anterior descending artery (LAD) and diagonal branch, a large septal branch originating from the LAD was accidentally and completely occluded. Septal Q waves then disappeared from leads I, V5 and V6, and ST segments were elevated in leads V1 to V3, with concomitant ST depressions in leads I, II, aVF, V5 and V6. It was speculated that the initial electrical potential derived from the central septum may have been lost due to septal infarction, resulting in the disappearance of the septal Q waves. The present case disclosed the role of the interventricular septum in the genesis of septal Q waves in the left precordial leads.