Truncus arteriosus communis is a rare CHD, accounting for only 1% of all congenital cardiac abnormalities. It has been associated with other malformations of the heart, mainly truncal valve (bicuspid/quadricuspid) and aortic arch abnormalities such as right, interrupted, and hypoplastic aortic arch. Cor tratriatrum sinistrum is another rare CHD, and it has been associated with other cardiac defects such as anomalous pulmonary venous drainage, ventricular septal defect, coarctation of the aorta, and tetralogy of Fallot. The combination of truncus arteriosus communis and cor tratriatrum sinistrum has not been reported so far. This case study describes the diagnosis of a unique case, including these two very rare cardiac defects and the successful surgical treatment thereafter.

Mitral valve stenosis caused by a discrete supravalvular membrane is a rare congenital malformation haemodynamically leading to significant mitral valve stenosis. When the supravalvular mitral stenosis consists of a discrete supravalvular membrane adherent to the mitral valve, it is usually not clearly detectable by routine echocardiography. We report about the typical echocardiographic finding in three young patients with this rare form of a discrete membranous supravalvular stenosis caused by a membrane adherent to the mitral valve. These cases present a typical echocardiographic feature in colour Doppler generated by the pathognomonic supramitral flow acceleration. Whereas typical supravalvular mitral stenosis caused by cor triatriatum or a clearly visible supravalvular ring is easily detectable by echocardiography, a discrete supravalvular membrane adjacent to the mitral valve leaflets resembling valvular mitral stenosis is difficult to differentiate by routine echocardiography. In our opinion, this colour phenomenon does resemble the visual impression of polar lights in the northern hemisphere; owing to its typical appearance, it may therefore be named as “Polar Light Sign”. This phenomenon may help to detect this anatomical entity by echocardiography in time and therefore improve the prognosis for repair.

There is ongoing debate regarding the initial management of symptomatic neonates with tetralogy of Fallot. Although neonatal repair can be performed with low mortality, it is associated with increased morbidity and long-term impact on right ventricular performance. Traditionally, the modified Blalock–Taussig shunt remains the palliative procedure of choice. Differential pulmonary artery flow may occur and subsequently result in underdevelopment and distortion of pulmonary vessels. Transcatheter therapy was previously limited to balloon valvulotomy when the obstruction is predominantly at the pulmonary valve level. Stenting of the right ventricular outflow tract can enable adequate forward flow; however, pulmonary regurgitation may impact on right ventricular performance and cardiac output. Stenting of the right ventricular outflow tract with valve sparing placement of the stent thus treating the underlying pathophysiology of the hypercyanotic spells provides a safe and effective management strategy, improving arterial oxygen saturation, avoiding pulmonary regurgitation and encouraging pulmonary artery growth.