A 31-year-old patient previously underwent a Mustard operation presented with palpitations. Atrial tachycardia and paroxysmal atrial fibrillation were documented on the surface electrocardiogram. Under the guidance of a three-dimensional electroanatomic mapping system, ablation of the isolated left-sided pulmonary vein and a cavo-tricuspid isthmus-dependent intra-atrial macro re-entry circuit eliminated atrial tachycardia and paroxysmal atrial fibrillation without the recurrence of atrial tachyarrhythmia.

The levoatriocardinal vein provides alternative egress from the left atrium to the systemic veins in left-sided obstructive lesions. Although rare, it has been described in association with hypoplastic left heart syndrome. We report a case of hypoplastic left heart syndrome with levoatriocardinal vein and aberrant right subclavian artery where cardiac magnetic resonance imaging/angiography proved to be a valuable imaging modality for pre-operative evaluation.

A 10-year-old boy with polyvalvular dysplasia and severe involvement of both atrioventricular valves presented with palpitations. Concern was raised for atrial tachyarrhythmia due to biatrial enlargement; however, ambulatory monitoring discovered a reentrant mechanism. Electrophysiology study revealed atypical atrioventricular nodal reentrant tachycardia involving two components of the slow pathway, with inputs in the posterior septum around his dysplastic tricuspid valve. He underwent successful modification of the slow pathway using cryoablation.

We present a case of atypical syncope in a 2-year-old, otherwise healthy girl. The patient presented with three episodes of syncope without any precipitating factors and no family history of sudden unexpected death. Holter monitoring revealed 24 events of complete atrioventricular block lasting up to 6 seconds. A normal 12-lead electrocardiogram does not necessarily exclude cardiac disease, and Holter monitoring is warranted in children with atypical syncope.

We present a case of congenital multiple coronary artery–left ventricle micro-fistulas, which were treated with propranolol disappearing within 6 months. She had a malformative syndrome associated with a chromosomal abnormality. The treatment for coronary artery fistula includes surgical ligation and transcatheter closure, but they are not indicated in congenital micro-fistulas. We propose propranolol as a treatment in this type of diffuse fistula.

It is controversial to observe or close symptomatic congenital coronary artery fistula in infants. We herein describe a medium-sized symptomatic congenital coronary artery fistula that underwent rapid spontaneous closure in an infant aged <3 months.

Left ventricular to right atrial communication is a rare congenital or acquired heart defect. There are many reports of successful transcatheter closure of this defect. We describe the device closure of one such communication in a 5-year-old girl using the Occlutech duct occluder. We believe that this device may have some advantages over the devices previously used for this purpose.

Diffuse aortitis, as seen in Takayasu disease, is characterised by extreme wall fragility, associated with a high risk of complications such as dissection and aneurysm formation, following endovascular treatment. We report a patient with Takayasu disease who presented with a very difficult clinical course associated with several unfavourable outcomes of stent insertion.

Chondrosarcoma is a malignant bone tumour common in adults, third to myeloma and osteosarcoma, but is exceptionally rare in children. Here we discuss a 9-year-old girl presenting with occlusive right pulmonary artery neoplastic embolus, resulting from a primary right proximal humerus chondrosarcoma. To the best of our knowledge, this the first pediatric and only second overall case reported in the United States of a neoplastic pulmonary embolus resulting from a primary chondrosarcoma.

A female baby suffered from a rare association between histiocytoid cardiomyopathy, left ventricular non-compaction, and Wolff–Parkinson–White syndrome causing severe and recurrent arrhythmic storms. Antiarrhythmic drugs, radiofrequency ablation of Purkinje tissue, and sympathetic denervation were ineffective. The implant of a cardiac defibrillator allowed her to survive till heart transplant. Compound mutation of CACNA2D1 and RANGRF genes were found. To the best of our knowledge, this is the first comprehensive description of the concurrence of these two mutations and histiocytoid cardiomyopathy.

Rhabdomyoma is the most common cardiac tumour in children often associated with tuberous sclerosis. Arrhythmia caused by cardiac rhabdomyomas may be the initial sign of tuberous sclerosis. Rhabdomyomas unresponsive to other treatments could be successfully managed with everolimus, which has demonstrated benefit in tuberous sclerosis. We report a case of rhabdomyoma causing severe arrhythmia in a newborn managed successfully with everolimus.

Here we report an infant with coronary artery fistulas. To clearly visualise the fistulas and surrounding materials, we utilised three-dimensional computed tomography, and the images were transferred as novel visualised three-dimensional images using a reconstruction technique. With the images, we could repair the fistulas accurately. We believe that these images are useful for repairing coronary artery fistulas in infants.

Congenital pericardial absence is a rare cardiac defect. Although most patients are asymptomatic, recognising this condition is clinically important as it can cause serious complications. We report the case of an asymptomatic 33-year-old woman seeking medical attention due to a family history of sudden cardiac death. The investigation led us to the diagnosis of congenital absence of the pericardium. The role of imaging in the diagnosis of this rare cardiac malformation is briefly discussed.

Acute myocardial infarction is rarely reported in children. Most of the cases are secondary to congenital anomalies or Kawasaki disease. Coronary artery total occlusion caused by fibromuscular dysplasia has never been reported in young children. Here we report a case of a 12-year-old boy with fibromuscular dysplasia, who underwent successful coronary intervention for acute myocardial infarction.

Klippel–Feil syndrome is a skeletal disorder characterised by low hairline and a short neck due to abnormal fusion of two or more cervical vertebrae. Although congenital heart and lung defects are infrequent, some abnormalities such as cor triatriatum, coarctation of the aorta, total anomalous pulmonary venous connection, or lung agenesis have been reported. The challenge of recognising Klippel–Feil syndrome lies in the fact that there is an association of this syndrome with other significant conditions such as skeletal, genitourinary, neurological, ear, and some cardiac defects. We report a Klippel–Feil syndrome type III 14-year-old patient with a levo-looped transposition of the great arteries. In addition, the patient had agenesis of the left upper-lung lobe.

Antiepileptic medications have been reported to cause disturbances in cardiac conduction. Lacosamide decreases seizure burden by modulating sodium channels. Although it has been demonstrated to have few side effects, there have been reports of clinically significant cardiac conduction disturbances. We report the case of a child with hypoplastic left-heart syndrome and well-controlled multifocal atrial tachycardia who developed haemodynamically significant atrial tachycardia after receiving two doses of lacosamide.