Cardiac MRI detected septal and lateral myocardial infarction by alcohol septal ablation through the intermediate artery.

A 65-year-old woman with hypertrophic obstructive cardiomyopathy presented with dyspnea. Transthoracic echocardiography showed severe mitral regurgitation (MR) due to systolic anterior motion and a peak gradient of 102 mmHg across the LV outflow. Cardiac magnetic resonance imaging (CMR) showed patchy late gadolinium enhancement in the hypertrophied septum. Because of non-responsiveness to medical treatment, percutaneous alcohol septal ablation (ASA) was conducted. The septal perforator that supplied the hypertrophic myocardium originated from the intermediate artery. A 2.0-mm over-the-wire balloon was used to occlude the intermediate artery and 1.1 ml of ethanol was injected slowly into the target septal perforator branch. The gradient decreased markedly to 5 mmHg immediately after ASA, and electrocardiogram showed right bundle branch block. Echocardiographic findings at 1 week were satisfactory. However, CMR showed delayed enhancement in both the hypertrophic basal septum and the lateral wall. The clinical course was uneventful, and she has maintained NHYA functional class 1 so far. In this case, proximal migration of the balloon or an undersized occluding balloon may have caused lateral infarction through leakage of ethanol into another branch. CMR is a useful modality to verify whether the ASA procedure has induced the appropriate controlled infarction.