Calmodulinopathies are rare life-threatening arrhythmia syndromes which affect mostly young individuals and are, caused by mutations in any of the three genes (CALM 1–3) that encode identical calmodulin proteins. We established the International Calmodulinopathy Registry (ICalmR) to understand the natural history, clinical features, and response to therapy of patients with a CALM-mediated arrhythmia syndrome. A dedicated Case Report File was created to collect demographic, clinical, and genetic information. ICalmR has enrolled 74 subjects, with a variant in the CALM1 (n = 36), CALM2 (n = 23), or CALM3 (n = 15) genes. Sixty-four (86.5%) were symptomatic and the 10-year cumulative mortality was 27%. The two prevalent phenotypes are long QT syndrome (LQTS; CALM-LQTS, n = 36, 49%) and catecholaminergic polymorphic ventricular tachycardia (CPVT; CALM-CPVT, n = 21, 28%). CALM-LQTS patients have extremely prolonged QTc intervals (594 ± 73 ms), high prevalence (78%) of life-threatening arrhythmias with median age at onset of 1.5 years [interquartile range (IQR) 0.1–5.5 years] and poor response to therapies. Most electrocardiograms (ECGs) show late onset peaked T waves. All CALM-CPVT patients were symptomatic with median age of onset of 6.0 years (IQR 3.0–8.5 years). Basal ECG frequently shows prominent U waves. Other CALM-related phenotypes are idiopathic ventricular fibrillation (IVF, n = 7), sudden unexplained death (SUD, n = 4), overlapping features of CPVT/LQTS (n = 3), and predominant neurological phenotype (n = 1). Cardiac structural abnormalities and neurological features were present in 18 and 13 patients, respectively. Calmodulinopathies are largely characterized by adrenergically-induced life-threatening arrhythmias. Available therapies are disquietingly insufficient, especially in CALM-LQTS. Combination therapy with drugs, sympathectomy, and devices should be considered.

Palliative Potts shunt has been proposed in children with suprasystemic pulmonary arterial hypertension (PAH). A retrospective multicentre study was performed to assess short- and long-term outcomes after Potts shunt. From 2003 to 2014, 24 children underwent a Potts shunt [19 surgical, median age: 7.7 years (1.5–17 years), median weight: 19.5 kg (10.2–47 kg) and 5 transcatheter, median age: 8.1 years (2.3–9.7 years), median weight: 22 kg (12.5–31 kg)] for drug-refractory PAH. For the first time in humans, we performed an unidirectional valved Potts anastomosis in a child with infrasystemic PAH on intravenous epoprostenol who experienced repeated central line infections. Severe postoperative complications occurred in 6 patients (25.0%, all from the surgical group) including 3 early deaths (12.5%) related to low cardiac output. After a median follow-up (FU) of 2.1 years (range, 3 months to 14.3 years, ≥8 years in 7 patients), World Health Organization (WHO) functional class was dramatically improved in the 21 survivors, all being in WHO-functional class 1 or 2 (P < 0.05); none experienced syncope during the FU; none had overt right ventricular failure; mean 6-min walk distance improved from 42.3 ± 10.0% to 81.2 ± 9.7% of adjusted values for age and sex (P < 0.001), BNP/NT-proBNP levels normalized in all; and weaning of intravenous epoprostenol was obtained in all patients who received triple combination as pre-Potts anastomosis therapy. Finally, all survivors caught up to normal growth curves. Arterial oxygen saturation gradient between upper and lower limbs persisted at the last FU (94.7 ± 3.6% vs 81.6 ± 5.1%, P < 0.001). One patient required double lung transplantation 6 years after a surgical Potts shunt. Palliative Potts shunt allows prolonged survival and dramatic, long-lasting improvement in functional capacities in children with severe, drug-refractory PAH. The Potts shunt might be considered as a first surgical or interventional step in the management of children with severe, drug-refractory PAH, leaving the door open for further lung transplantation, if needed.

Atrioventricular block is classified as congenital if diagnosed in utero, at birth, or within the first month of life. The pathophysiological process is believed to be due to immune-mediated injury of the conduction system, which occurs as a result of transplacental passage of maternal anti-SSA/Ro-SSB/La antibodies. Childhood atrioventricular block is therefore diagnosed between the first month and the 18th year of life. Genetic variants in multiple genes have been described to date in the pathogenesis of inherited progressive cardiac conduction disorders. Indications and techniques of cardiac pacing have also evolved to allow safe permanent cardiac pacing in almost all patients, including those with structural heart abnormalities. Conclusion: Early diagnosis and appropriate management are critical in many cases in order to prevent sudden death, and this review critically assesses our current understanding of the pathogenetic mechanisms, clinical course, and optimal management of congenital and childhood AV block. What is Known: • Prevalence of congenital heart block of 1 per 15,000 to 20,000 live births. AV block is defined as congenital if diagnosed in utero, at birth, or within the first month of life, whereas childhood AV block is diagnosed between the first month and the 18th year of life. As a result of several different etiologies, congenital and childhood atrioventricular block may occur in an entirely structurally normal heart or in association with concomitant congenital heart disease. Cardiac pacing is indicated in symptomatic patients and has several prophylactic indications in asymptomatic patients to prevent sudden death. • Autoimmune, congenital AV block is associated with a high neonatal mortality rate and development of dilated cardiomyopathy in 5 to 30 % cases. What is New: • Several genes including SCN5A have been implicated in autosomal dominant forms of familial progressive cardiac conduction disorders. • Leadless pacemaker technology and gene therapy for biological pacing are promising research fields. In utero percutaneous pacing appears to be at high risk and needs further development before it can be adopted into routine clinical practice. Cardiac resynchronization therapy is of proven value in case of pacing-induced cardiomyopathy.

Congenitally corrected transposition of the great arteries (ccTGA) is a rare cardiac malformation characterized by the combination of discordant atrioventricular and ventriculoarterial connections.[1][1] The incidence has been reported to be around 1/33 000 live births, accounting for ≈0.05% of