Differential diagnosis, interventions and treatment:
Treatment with the β-blocker cibenzoline and temporal right ventricular pacing did not relieve the heart failure or severe LVOT obstruction. Because the patient was at high risk for surgery, we elected to proceed with urgent PTSMA.
The first to third septal perforator arteries were accessed for ablation (Figure 2a) using a guidewire (Sion Blue, Asahi Intecc USA Inc., Santa Ana, CA, USA), then a 1.2 × 6 and 1.5 × 6-mm Mini Trek balloon (Abbott) was inflated. Contrast agent was selectively injected distal to the occlusive balloon, and simultaneous transthoracic echocardiography revealed clear delineation of the proximal septum supplied by this vessel (Figure 2, lower panels). Absolute alcohol (6.7 mL) was injected distal to the occlusive balloon over a period of 40 min.
The intraventricular pressure gradient (20 mmHg) and mitral regurgitation induced by SAM were quickly resolved by PTMA. No peri-procedural complications developed. Final coronary angiography after alcohol injection showed occluded target septal arteries and no damage to the left anterior descending artery (LAD; Figure 2b). Peak creatinine kinase and creatinine kinase-MB values were 1,693 and 363 IU/L, respectively.