Interventricular Septal Hematoma Complicating Left Branch Bundle Lead Implantation

We present a female patient with heart failure with reduced ejection fraction who underwent left bundle branch cardiac resynchronization therapy. Left bundle branch lead implantation was complicated with septal branch perforation causing an iatrogenic coronary fistula complicated by septal hematoma formation and development of shock. Occlusion by covered stents was successfully achieved. (Level of Difficulty: Advanced.