The reverse CART technique provides the potential to modify the retrograde procedure by improving the controlled movement of the retrograde wire and improve the success rates of percutaneous coronary intervention (PCI) of chronic total occlusion (CTO). Development of interventricular hematoma is a rare complication of CTO PCI. A 63-year-old man with effort angina with a right coronary artery CTO lesion underwent PCI by retrograde approach from the LAD to a septal branch. A contrast "stain" was demonstrated surrounding the septal collateral channel used for the retrograde approach at the end of the procedure without symptom. Echocardiography indicated an increased interventricular septum thickness with low echo signals region and decreased contractility. Cardiac magnetic resonance (CMR) imaging using gadolinium showed a diffusely thickened septum with a low signal fusiform neocavitation delimited by an enhanced-signal ring suggesting intraventricular septal dissecting hematoma. After conservative treatment, follow-up echocardiogram and CMR showed the resolution of the hematoma without clinical events. This case highlights the potentially lethal complication of septal perforator dissection and hematoma that may cause severe myocardial injury caused by retrograde approach for CTO PCI.