A young child presented with hepatomegaly, ascites and bradycardia in the setting of COVID-19. Permanent complete atrioventricular block and severe right heart failure were diagnosed. He was treated with surgical epicardial pacemaker implantation. This report is the first description of COVID-19-induced permanent complete atrioventricular block in a child.

Sialidosis, a rare autosomal recessive disorder, is caused by a deficiency of NEU1 encoded enzyme alpha-N-acetyl neuraminidase. We report a premature male with neonatal-onset type II sialidosis which was associated with left ventricular dysfunction. The clinical presentation and subsequent progression which culminated in his untimely death at 16 months of age are succinctly described. Early-onset cardiovascular involvement as noted in this patient is not well characterised. The case report is supplemented by a comprehensive review of the determinants, characteristics, and the clinical course of cardiovascular involvement in this rare condition.

A 21-year-old man with Wolff–Parkinson–White syndrome and aneurysmal septal dyskinesis underwent radiofrequency catheter ablation of the accessory pathways. Before radiofrequency catheter ablation, the activation wavefront arose from the aneurysmal septum, whereas the propagation of the left ventricle was normalised after radiofrequency catheter ablation. These findings demonstrate the importance of the electro-mechanical interaction in patients with Wolff–Parkinson–White syndrome and ventricular dysfunction.

We hypothesised that infants with ventricular dysfunction after cardiac surgery have impaired haemodynamic response to arginine–vasopressin therapy. We retrospectively reviewed the medical records of neonates and infants treated with arginine–vasopressin within 48 hours of corrective or palliative cardiac surgery who underwent echocardiographic assessment of ventricular function before initiation of therapy. Patients were classified as “responders” if their systolic blood pressure increased by ⩾10% without increase in catecholamine score or if it was maintained with decreased catecholamine score. Response was assessed 1 hour after maximum upward titration of arginine–vasopressin. A total of 36 children (15 neonates) were reviewed (17 male). The median (interquartile) age was 10.4 weeks (1.1–26.9), and the median weight was 4.3 kg (3.2–5.8). Diagnoses included single ventricle (eight), arch abnormalities (five), atrioventricular septal defect (four), double-outlet right ventricle (three), tetralogy of Fallot (three), and others (13). In all, 12 patients (33%) had ventricular dysfunction. Only 15 (42%) responded favourably according to our definition 1 hour after the “target” arginine–vasopressin dose was achieved. Ventricular dysfunction was not associated with poor response. The overall mortality was 25%, but mortality in patients with ventricular dysfunction was 42%. Favourable response was associated with shorter ICU stay (9.5 days versus 19.5 days, p=0.01). We conclude that arginine–vasopressin fails to increase blood pressure in ~50% of hypotensive children after cardiac surgery. The response rate does not increase with duration of therapy. Ventricular function does not predict haemodynamic response. The mortality in this group is very high. Prospective comparison of vasopressin with other vasoactive agents and/or inotropes is warranted.

Acute heart failure related to anaphylactic shock is often reversible and necessitates aggressive support to ensure full recovery. We report the case of a 15-year-old boy who developed severe ventricular dysfunction and haemodynamic instability after administration of amiodarone and required temporary mechanical circulatory support with a left ventricular assist device. He had full recovery of cardiac function and returned to baseline neurologic status. This is the first report of successful left ventricular assist device use for recovery from cardiovascular collapse due to anaphylaxis.

In paediatric pulmonary embolism, cardiac findings and thromboembolic outcomes are poorly defined. We conducted a mixed retrospective-prospective cohort study of paediatric pulmonary embolism at the Children's Hospital Colorado between March, 2006 and January, 2011. A total of 58 consecutive children – age less than or equal to 21 years – with acute pulmonary embolism were enrolled. Data collection included clinical and laboratory characteristics, treatments, serial echocardiographic and electrocardiographic findings, and outcomes of pulmonary embolism non-resolution and recurrence. The median age was 16.5 years ranging from 0 to 21 years. The most prevalent clinical risk factors were oral contraceptive pill use (52% of female patients), presence of a non-infectious inflammatory condition (21%), and trauma (21%). Thrombophilias included heterozygous factor V Leiden in 21%; antiphospholipid antibody syndrome was established in 31% overall. Proximal pulmonary artery involvement was present in 34%. At presentation, nearly half of the patients had hypoxaemia and 37% had tachycardia. The classic electrocardiographic finding of S1Q3T3 was present in 12% acutely; tricuspid regurgitation greater than 3 metres per second, septal flattening, and right ventricular dilation were each present on acute echocardiogram in 25%. Nearly all patients received therapeutic anticoagulation, with initial systemic tissue plasminogen activator administered in 16% for occlusive iliofemoral deep venous thrombosis and/or massive pulmonary embolism. Pulmonary embolism resolution was observed in 82% by 6 months. Recurrent pulmonary embolism occurred in 9%. There were no pulmonary embolism-related deaths. Right ventricular dysfunction was rare in follow-up. These data indicate that acute heart strain is common, but chronic cardiac dysfunction is rare, following aggressive management of acute pulmonary embolism in children.

Paediatric myocarditis remains challenging from the perspectives of diagnosis and management. Multiple aetiologies exist and the majority of cases appear to be related to viral illnesses. Enteroviruses are believed to be the most common cause, although cases related to adenovirus may be more frequent than suspected. The clinical presentation is extremely varied, ranging from asymptomatic to sudden unexpected death. A high index of suspicion is crucial. There is emerging evidence to support investigations such as serum N-terminal B-type natriuretic peptide levels, as well as cardiac magnetic resonance imaging as adjuncts to the clinical diagnosis. In the future, these may reduce the necessity for invasive methods, such as endomyocardial biopsy, which remain the gold standard. Management generally includes supportive care, consisting of cardiac failure medical management, with the potential for mechanical support and cardiac transplantation. Treatments aimed at immunosuppression remain controversial. The paediatric literature is extremely limited with no conclusive evidence to support or refute these strategies. This article summarises the current literature regarding aetiology, clinical presentation, diagnosis, and management of myocarditis in paediatric patients.

An eight-month-old girl with hypoplastic left heart syndrome, who underwent a modified Norwood operation at the age of two days, and a Hemifontan operation at five months of age, had severely impaired ventricular function and new electrocardiographic changes. Coronary angiography demonstrated a small adherent thrombus in the non-coronary sinus of Valsalva of the native aortic root, which may be the cause of unexplained ventricular dysfunction.