Isolated pericardial agenesis revealed by bradycardia and heart MRI in a healthy 5-year-old child

We present a five-year-old boy with an unremarkable medical history who was incidentally found to have bradycardia and electrocardiographic signs of right axial deviation. Initial echocardiogram showed left displacement of the cardiac apex with slight enlargement of the right ventricle, while frontal chest radiograph showed a lucent area between the aorta and pulmonary artery. Cardiac magnetic resonance imaging finally revealed a partial left pericardial agenesis and abnormal displacement of the heart into the left hemithorax.