The extracardiac conduit-Fontan (ECC) has become the preferred technique for univentricular heart palliation, but there are currently no data on the incidence of long-term arrhythmias. This study investigated the incidence of arrhythmias and relation to single ventricle morphology in the long-term follow-up (FU) in ECC. All patients with ECC performed in our Centre between 1987 and 2017 were included (minimum FU 5 years). Of 353 consecutive patients, 303 [57.8% males, aging 8–50 (median 20) years at last FU] were considered and divided into two groups depending on left (194 in Group 1) or right (109 in Group 2) ventricular morphology. Eighty-five (28%) experienced ≥1 arrhythmic complications, with early and late arrhythmias in 17 (5.6%) and 73 (24.1%) patients, respectively. Notably, late bradyarrhythmias occurred after 6 years in 21 (11%) patients in Group 1, and in 15 (13.8%) in Group 2 [P = 0.48]. Late tachyarrhythmias occurred in 55 (18.2%) patients after 12 years: 33 (17%) in Group 1 and 22 (20.2%) patients in Group 2 [P = 0.5]. Ventricular tachycardias (VT) were documented after 12.5 years in 14 (7.2%) patients of Group 1 and 15 (13.8%) of Group 2 [P = 0.06] with a higher incidence in Group 2 during the FU [P = 0.005]. Extracardiac conduit is related to a significant arrhythmic risk in the long-term FU, higher than previously reported. Bradyarrhythmias occur earlier but are less frequent than tachyarrhythmias. Interestingly, patients with systemic right ventricle have a significantly higher incidence of VT, especially in a very long FU.

We derived reference values of left-ventricular (LV) and right-ventricular (RV) strain parameters in a cohort of 100 healthy subjects by feature tracking cardiac magnetic resonance (FT-CMR). Global and regional strain values were calculated for the LV; circumferential and radial_SAX strain parameters were derived from the short-axis (SAX) stack, while longitudinal and radial_LAX strain parameters were assessed in three long-axis (LAX) views. Only global longitudinal strain (GLS) was calculated for the RV. Peak global LV circumferential strain was −16.7% ± 2.1%, LV radial_SAX strain was 26.4% ± 5.1%, LV radial_LAX strain was 31.1% ± 5.2%, LV GLS was −17.7% ± 1.9%, and RV GLS was −23.9% ± 4.1%. Women presented higher global LV and RV strain values than men; all strain values presented a weak relationship with body surface area, while there was no association with age or heart rate. A significant association was detected between all LV global strain measures and LV ejection fraction, while RV GLS was correlated to RV end-diastolic volume. The intra- and inter-operator reproducibility was good for all global strain measures. In the regional analysis, circumferential and radial strain values resulted higher at the apical level, while longitudinal strain values were higher at the basal level. The assessment of cardiac deformation by FT-CMR is feasible and reproducible and gender-specific reference values should be used.

Introduction: The aim of the study was to revise our more recent experience about epicardial posterior-septal accessory pathways radiofrequency transcatheter ablation in children and young patients using a transvenous approach through the coronary sinus, to understand if new mapping and ablation technologies can increase success rate and safety.Methods and results: Twenty children (mean age 13 ± 3 years) with epicardial posterior-septal accessory pathways (14 in coronary sinus and 6 in the middle cardiac vein) underwent radiofrequency transcatheter ablation with CARTO-3® system with help of the CARTO-Univu® module. Acute success rate was 73%. No patient was lost to follow-up (mean time 11.4 ± 9 months). The recurrence rate was 19%. Two patients underwent a successful redo-procedure; the overall long-term success rate was 65%. Navistar® catheter presented the highest acute success rate in the coronary sinus. Navistar SmartTouch® was the only catheter that did not present recurrences after the acute success, and it was successfully used in two patients previously unsuccessfully treated with a Navistar ThermoCool®. Acute success rate was 79% without image integration with angio-CT, while it was 63% after the introduction of CARTO-Merge®.Conclusion: Epicardial posterior-septal accessory pathways can be definitively eliminated by transvenous radiofrequency transcatheter ablation in more than half of the cases in children. Acute success rate does not seem to depend on catheters used, but contact-force catheter seems to be useful in cases with recurrences. Image integration with cardiac-CT does not increase success rate, but it is useful to detect coronary sinus alterations to better guide ablation strategy.

Ventricular preexcitation (VP) may be intermittent in some patients. Historically, this has been thought to indicate a low-risk accessory pathway (AP) that conducts poorly in the anterograde direction.¹ However, rare cases of sudden cardiac death (SCD) in intermittent ventricular preexcitation (IVP) have been reported since the 1980s, and recently growing data have highlighted the potential risk of adverse events, even in patients with IVP.^2,3 Therefore, the most recent guidelines on asymptomatic VP in young patients suggest invasive risk stratification with electrophysiological testing (EPT) in these patients.^3,4

Main pulmonary artery (mPA) dilatation has been reported in patients with isolated pulmonary valve (PV) stenosis. The aim of our study was to detect the incidence of mPA dilatation and aneurysm in patients with isolated PV stenosis and the association with PV function. In this single-centre retrospective observational study all patients with a diagnosis of isolated PV stenosis referred to our centre were enrolled. Patients were divided into two groups (children and adults) according to age. Echocardiography, cardiac magnetic resonance imaging (MRI) and computed tomography (CT) were reviewed. MPA dilatation was defined as ≥2 Z-Score in children and ≥30mm diameters in adults, while giant (aneurysmal) mPA dilatation was defined as ≥4 Z-Score in children and ≥40mm in adults. Out of 197 patients (41.6% males, 51.8% children), 67.2% presented mPA dilatation and 16.8% giant dilatation of the mPA. The majority were adults (p<0.001). There was an underestimation of the mPA with echocardiography in 11% of patients with mPA dilatation and 50% with giant mPA. The diameter did not correlate with sex and the degree of PV stenosis. About 44% of cohort under follow-up presented a progression in mPA dilatation, however no rupture or cardiac-related death was reported. There is a very high incidence of mPA dilatation in both adults and paediatric patients with isolated PV stenosis. Nevertheless, there were not recorded dissections even in patients with the largest diameters suggesting a more benign lesion. Echocardiography often underestimates the mPA measurement compared to MRI/CT which might be indicated in selected patients as a baseline 3D cross-sectional imaging evaluation, even in the presence of mild PV disease, especially when the mPA is not well visualised.