Differential diagnosis of an intracardiac mass is difficult when detected only by echocardiography before a biopsy is completed. However, treatment cannot be postponed until the biopsy results are obtained. We report the case of a 12-year-old girl who presented with an intracardiac mass in the mitral valve mimicking infective endocarditis and severe mitral regurgitation. The mass was finally diagnosed as valvulitis associated with systemic juvenile idiopathic arthritis, which was complicated with macrophage activation syndrome. After careful exclusion of acute infectious disease, we started steroid pulse therapy and administered tocilizumab to treat the cytokine storm before performing the surgery. Finally, we performed mass excision and mitral valve replacement after immunosuppressant therapy.

We report a case of an isolated congenital right ventricular outpouching detected incidentally on foetal echocardiogram that was performed due to suspicion of CHD. Subsequent echocardiogram after birth revealed an aneurysm with features of a pseudoaneurysm having a thin and hypokinetic wall connected to the ventricleʼs cavity via a narrow neck. This pseudoaneurysm appears to be stable in size and of no clinical significance during the short-term follow-up.

A 24-year-old female patient diagnosed with cyanotic CHD had undergone a correction procedure at the age of eight. She had a normal motor and mental development until the age of 23. Later she had functional and cognitive decline following heart failure. Brain MRI showed enlargement of the cerebral arterial and venous system. The changes of central nervous system vasculature occurring in operated cyanotic CHD are not well known. Thanks to advances in this field, more cyanotic CHD patients reach adulthood nowadays and clinicians need to be familiar with the neurological conditions and potential neuroradiological changes.

We report a case of a 15-year-old female who underwent combined hybrid pulmonary valve replacement and transcatheter atrial septal defect device closure, which was performed due to severe volume overload of the right side of the heart secondary to pulmonary regurgitation and atrial septal defect.

Symptomatic, circulatory collapse occurred in an unvaccinated child with repaired congenital heart and a backup pacemaker during an Influenza B viral infection with complete atrioventricular block and pacemaker non-capture. Ventricular arrhythmias occurred during her collapse. Atrioventricular conduction recovered within 24 hours. Influenza-associated cardiac inflammation can adversely affect patients with repaired CHD. Proactive immunisation is strongly recommended.

Left ventricular pseudoaneurysm is very rare in children. Although surgery is conventional treatment, recently, percutaneous closure of pseudoaneurysms has been described. Here, we present the first case where a patient developed left ventricular pseudoaneurysm after percutaneous ventricular septal defect device closure and was treated by a second percutaneous method.

Branch pulmonary artery valve implantation has been reported in larger patients with dysfunctional right ventricular outflow tracts via routine femoral access. Here, we report treatment of severe pulmonary insufficiency with bilateral branch pulmonary artery Melody valve implantation (Medtronic, Minneapolis, Minnesota). To the best of our knowledge, this is the first report of bilateral valve implantation utilising the hybrid approach in a small-size patient.