A 15-year-old boy was admitted to the emergency department with arthralgia of the knee. He was diagnosed with acute rheumatic fever based on clinical examination, electrocardiography, echocardiography, and elevated inflammatory markers including C-reactive protein, erythrocyte sedimentation rate, and anti-streptolysin O titre. First-degree and second-degree Mobitz type 1 atrioventricular blocks, moderate frequency uniform ventricular premature beats, as well as non-sustained ventricular tachycardia, were detected on 24-hour Holter electrocardiography monitoring.

Cardiac rhabdomyomas are associated with ventricular arrhythmias, but mechanisms remain uncertain. A 10-year-old boy with tuberous sclerosis complex developed verapamil-sensitive fascicular ventricular tachycardia adjacent to a residual cardiac rhabdomyoma. Electrophysiological mapping demonstrated Purkinje-mediated reentry. Catheter ablation at a tumour-adjacent site eliminated the arrhythmia, suggesting that residual rhabdomyoma may anchor a localised reentrant substrate.

Acute rheumatic fever is classically associated with carditis, particularly when erythema marginatum and subcutaneous nodules are present. We report a 13-year-old boy who fulfilled three major Jones manifestations-migratory polyarthritis, erythema marginatum, and subcutaneous nodules-supported by evidence of recent streptococcal infection, yet had no clinical, electrocardiographic, or echocardiographic evidence of carditis on serial assessment over three months. Serial photographs documented the evolving morphology of erythema marginatum in dark skin. A transient ocular inflammatory episode occurred during convalescence. This case highlights an uncommon phenotype of acute rheumatic fever and underscores the importance of recognising major extracardiac manifestations even when the heart remains unaffected.

Chronic haemolysis is a rare but important postsurgical complication in children with congenital heart defects. A 13-year-old with a previously uncorrected complex heart defect underwent corrective surgery. He developed haemolysis postoperatively. A mechanical cause due to turbulent flow through a narrowed intraventricular Dacron patch tunnel was suspected. Balloon dilatation and stent placement successfully resolved the stenosis and haemolysis.