International Cohort of Neonatal Timothy Syndrome.

INTRODUCTION: Timothy syndrome (TS) is an extremely rare, multisystem disorder classically associated with long QT, syndactyly, ventricular arrhythmias, and hypoglycaemia. A neonatal diagnosis allows maximal medical and device therapy to be implemented to avoid malignant arrhythmias and sudden cardiac death. METHODS: This was a retrospective case series study of type I TS (TS1) patients using data from the Timothy Syndrome Foundation's international registry, encompassing patients with a genetic diagnosis (CACNA1C variant G406R in exon 8A) recruited over a 28-year period. RESULTS: Forty-four cases of TS1 were included (26 male; 60%). Mean gestational age (GA) was 35.6 weeks (range 28 weeks - term), with 43% of patients born less than 37 weeks GA. In TS1 patients presenting with foetal bradycardia, mean GA was significantly lower (34.2 weeks, p < 0.05). Foetal bradycardia secondary to atrioventricular block was present in 20 patients (45%), resulting in premature delivery in 14 patients (32%). Fifteen patients (34%) were diagnosed with TS1 as neonates. Long QT at birth helped secure a diagnosis in 25 patients (57%). Syndactyly was seen in most patients (n = 40, 91%). Twenty patients died, with an average age of death of 2.3 years (range 1 month-6 years). Of the 7 patients who died before the first year of life (16%), the average age of death was 2.5 months. CONCLUSION: TS is associated with high early mortality. TS should be considered in paediatric patients presenting with long QT and syndactyly. Recognition of TS in the neonatal period allows for early intervention to prevent life-threatening arrhythmias.

Preliminary assessment of paediatric electrophysiology cardiac implantable electronic device resources around the world.

BACKGROUND: The Pediatric and Congenital Electrophysiology Society (PACES) is a global organisation committed to the care of children and adults with CHD and arrhythmias. OBJECTIVE: To evaluate the global needs and potential inequities as it relates to cardiac implantable electronic devices. METHODS: ARROW (Assessment of Rhythm Resources arOund the World) is an online survey about cardiac implantable electronic devices, sent electronically to physicians within the field of Cardiology, Pediatric Cardiology, Electrophysiology and Pediatric Electrophysiology. RESULTS: ARROW received 42 responders from 28 countries, 50% from low-/middle-income regions. The main differences between low-/middle- and high-income regions include availability of expertise on paediatric electrophysiology (50% versus 93%, p < 00.5) and possibility to perform invasive procedures (35% versus 93%, p < 0.005). Implant of devices in low-income areas relies significantly on patient's resources (71%). The follow-up of the devices is on the hands of paediatric cardiologist/electrophysiologist in higher resources centres (93% versus 50%, p < 0.05). CONCLUSIONS: The ARROW survey represents an initial assessment of the geographical characteristics in the field of Pediatric Electrophysiology. The next step is to make this "state of the art" more extensive to other aspects of the expertise. The relevance of collecting this data before the World Congress of Pediatric Cardiology and Cardiac Surgery (WCPCCS) in 2023 in Washington DC was emphasised in order to share the resulting information with the international community and set a plan of action to assist the development of arrhythmia services for children within developing regions of the world.

Ventricular Arrhythmia and Life-Threatening Events in Patients With Repaired Tetralogy of Fallot.

Risk stratification for malignant arrhythmias and risk of sudden cardiac death in tetralogy of Fallot (TOF) remains challenging. We aimed to ascertain factors associated with life-threatening arrhythmic events. A multicenter retrospective case-control study including 72 TOF patients with documented cardiac arrest and/or sustained ventricular tachycardia, compared with 216 controls matched for era of surgery. The mean age at event in the cases was 27.3 ± 12.5 years. The majority (57%) presented with sustained ventricular tachycardia. Fatal events occurred in 9. Random forest analysis and a decision tree demonstrated surgical era specific risk factors (< vs ≥ 1980). For both eras, arrhythmic symptoms and left ventricular dysfunction were strongly associated with malignant arrhythmias. In addition, right ventricular dysfunction and age at repair ≥ 6.5 years preceded by a shunt were associated with a higher risk group in the early era, whereas a trans-annular patch type repair was associated with a lower risk group in the recent era. For the moderate and high-risk groups, the decision tree showed a sensitivity of 88.4% and specificity of 68.1%. An "importance factor" was calculated for each predictor, creating a risk score and 4 risk categories. In conclusions, this risk stratification scheme, based on clinical history and noninvasive testing, allows categorization of TOF patients at high risk of malignant arrhythmia. A multicenter prospective evaluation of the accuracy of this scoring system is now being planned.

Long-term results of atrial maze surgery in patients with congenital heart disease.

AIMS: Recurrent atrial tachycardia is common after repair of many types of congenital heart disease, and surgical ablation with a maze procedure represents a potential treatment strategy. The objective of this study is to report a single-centre 19 years' experience with maze surgery in congenital heart patients. METHODS AND RESULTS: Patients undergoing maze procedure concomitantly with cardiac surgical procedures were retrospectively analysed. The maze procedure was classified as therapeutic if the patient demonstrated preoperative atrial arrhythmias, or as prophylactic if done because the patient was considered high risk for post-operative arrhythmias. Acute outcomes and longer-term freedom from atrial arrhythmias were analysed. Maze surgery was performed in 166 patients: 137 in the therapeutic group, and 29 in the prophylactic group. The most common congenital heart lesion was single ventricle for the therapeutic group (27%) and Ebstein's anomaly for the prophylactic group (76%). Surgery consisted of a right atrial maze in 63%, left atrial maze in 4%, and bilateral maze in 33%. There were no direct complications or mortality related to the maze procedure itself. For the therapeutic group, freedom from arrhythmias was 82% and 67% at 1 and 5 years post-maze. Younger age at the time of surgery correlated with a lower long-term recurrence risk. CONCLUSION: Maze procedure at the time of an elective anatomic surgery is reasonably effective to prevent and treat atrial arrhythmias in patients with congenital heart disease at short- and mid-term, with low morbidity and mortality.