An 8-week-old premature female infant, born at 24 weeks’ gestation, with a hemodynamically significant patent ductus arteriosus (PDA) was referred for transcatheter PDA closure. During catheter manipulation, advancement of a guidewire and microcatheter resulted in perforation of the right ventricular outflow tract with inadvertent injection of contrast into the pericardial sac. The injury was immediately recognized, and the intervention was aborted. a Post-procedural chest radiography demonstrated contrast opacification of the pericardial sac, producing a pericardiogram. b Image from the catheterization procedure shows contrast opacifying the pericardial sac, rather than the intended right ventricular outflow tract. Despite the perforation, the infant remained hemodynamically stable, and pericardial drainage was not required. Conservative management, including close clinical monitoring and serial imaging, was pursued. Cardiac perforation during catheterization in premature infants is rare but can occur due to the inherently thinned right ventricular free wall and outflow tract.