Post-cardiac injury syndrome (PCIS) is one of the complications of cardiac interventional procedures. This condition has been postulated to be due to an immune reaction, especially with pacemaker lead implantation. Patients with PCIS can have uncomplicated pericardial effusion until they develop cardiac tamponade. The management of PCIS, which can be conservative management or require pericardiocentesis or surgery depends on the patient's clinical symptoms. As the left bundle branch area pacing (LBBAP) implantation technique and technology are still new, it is associated with longer procedural time than conventional pacemaker implantation. Herein, we report a case of PCIS in a patient who had a prolonged LBBAP procedure due to difficult anatomy and presented with recurrent cardiac tamponade.LEARNING POINTS: Prolonged fluoroscopy in cardiac procedures can potentially lead to post-cardiac injury syndrome.Active pacemaker lead fixation is one of the risk factors for post-cardiac injury syndrome due to immune reaction.Left bundle branch area pacing in adults with congenital heart disease is challenging because of anatomical differences.