Background: Conotruncal anomalies frequently involve extracardiac vascular structures that are critical for surgical planning yet incompletely assessed by transthoracic echocardiography (TTE). We evaluated the incremental diagnostic value of CT angiography (CTA) beyond TTE using intraoperative findings as the reference standard. Methods: In this single-center retrospective study, 239 children who underwent surgical repair of a conotruncal anomaly and had both preoperative TTE and CTA were analyzed. The incremental contribution of CTA was graded as none, minor, or major by two independent reviewers. Diagnostic performance of each modality was compared with operative findings for coronary artery anomalies, right aortic arch, aortic arch hypoplasia, interrupted aortic arch, and pulmonary artery atresia, non-confluence, and hypoplasia. Results: CTA provided incremental information beyond TTE in 232 patients (97.1%), classified as major in 51.9% and minor in 45.2%; interobserver agreement was almost perfect (quadratic-weighted κ = 0.825). CTA was superior for coronary artery anomalies (sensitivity 91.7% vs. 50.0%), branch pulmonary artery hypoplasia (97.3% vs. 89.3%), and aortic arch hypoplasia (100% vs. 87.5%; all p < 0.05), and identified aortopulmonary collaterals and a persistent left superior vena cava more frequently than TTE. The two modalities performed comparably for aortic arch sidedness and interrupted aortic arch, and pulmonary atresia. Conclusions: CTA provides additional, operatively confirmed anatomical information beyond TTE in the majority of children with conotruncal anomalies, with the greatest value for extracardiac vascular anatomy. Rather than replacing echocardiography, CTA should be regarded as a complementary modality that refines preoperative anatomical assessment.

Background/Objectives: Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect, and cardiac computed tomography (CT) is increasingly central to its anatomical and pre-procedural assessment. Artificial-intelligence research in TOF is dominated by MRI; deep learning on cardiac CT in congenital heart disease exists but addresses multi-class diagnosis and segmentation, and the one binary TOF-versus-control CT study used slice-level validation without confounder control, and, to our knowledge, no CT study reports controlling the confounding intrinsic to a TOF-versus-control comparison. This confounding is structural: TOF is imaged predominantly in infancy, so a naive classifier can learn age, body size, and acquisition protocol rather than pathology. We develop and internally evaluate a confounder-matched, anatomy-guided deep-learning pipeline for TOF on cardiac CT. Methods: Contrast-enhanced cardiac CT from a single scanner was de-identified and restricted to one reconstruction (FC15 kernel, 0.5 mm), then matched 1:1 on age and sex, yielding 42 TOF and 42 controls (n = 84); controls were children imaged for suspected but excluded cardiovascular disease, so scan indication, unlike age and sex, was not matched. Standardized volumes were decomposed into four fixed sub-volumes positioned to approximate the components of the diagnostic tetrad: malalignment ventricular septal defect (VSD), overriding aorta, right-ventricular outflow tract (RVOT), and right-ventricular hypertrophy (RVH). Whether each sub-volume contains its named target was audited against independent physician region-of-interest annotations. Per region, a 2.5D transfer-learning classifier (ImageNet ResNet18) and a 3D CNN (DenseNet121) were trained with leak-free patient-level five-fold cross-validation and the branches fused. Optimism was assessed by repeated cross-validation and, for model selection, by nested cross-validation with the component subset and operating point chosen inside an inner loop. Discrimination was reported with bootstrap 95% confidence intervals (CIs); AUROCs were compared by DeLong test, with Benjamini–Hochberg correction applied to a seven-member family (the four within-component comparisons, two hybrid-versus-VSD contrasts, and hybrid versus whole-heart) and other comparisons reported uncorrected. Results: Matching removed the age difference (median 0.33 years, IQR 0.17–0.92 vs. 0.33, IQR 0.27–0.73; p = 0.86) with balanced sex (p = 1.00). The pre-specified four-component hybrid reached AUROC 0.829 (95% CI 0.74–0.91); the VSD region alone reached 0.828 (0.74–0.91), so the tetrad decomposition did not improve accuracy, and the containment audit shows it does not deliver the intended anatomical interpretability either. The 2.5D model exceeded the 3D CNN for every component (0.769–0.828 vs. 0.573–0.656; raw DeLong p = 0.007–0.037, Benjamini–Hochberg q up to 0.065 under a seven-member family, the weakest comparison (RVH) not surviving correction). Repeated cross-validation gave 0.811 ± 0.026 and nested cross-validation 0.787 ± 0.029; a stronger backbone with multi-phase data, handcrafted radiomics, and a large CT foundation model did not significantly improve on the matched pipeline. Grad-CAM maps were sensitive to both model weights and labels and superior to a centred-blob null in all eight comparisons and significantly so in seven, but not consistently superior to a resolution-matched random attribution, so no localization claim is made. Calibration was imperfect (slope 0.67) and recalibration gave no net gain; at an in-sample Youden threshold sensitivity was 0.93 and specificity 0.64. Occlusion sensitivity on the whole-heart baseline model showed it relies on the physician-marked septal, aortic and right-ventricular sites 1.8–4.1 times more than distance-matched surrounding tissue, while gross morphometry alone reached 0.651–0.663. Two of the four sub-volumes did not contain their target: the RVOT prior contained the physician annotation in 48.1% of cases and, because the model samples only the central band, excluded it in 99.4%; the RVH box was offset toward the midline, containing the marked target in 43.4% of annotations. Repositioning the priors, leak-free and derived from controls only, did not change discrimination (all p ≥ 0.10), and boxes placed at random positions inside the standardized heart reached 0.765 on average against 0.796 for the published priors, a difference this cohort cannot resolve. Conclusions: As a proof of concept, confounder-matched deep learning can recognize TOF on cardiac CT. Increasing model capacity did not significantly improve on the matched pipeline; the separate contribution of matching itself was not isolated against an unmatched comparator. Given the small, single-centre sample and the absence of external validation, these findings are hypothesis-generating and require external, multi-centre confirmation before any clinical use.

Neonatal arrhythmias, though relatively uncommon, can range from benign self-limiting conditions to life-threatening disorders requiring intensive management. Data on their clinical spectrum, management, and outcomes remain limited. This study aimed to evaluate the types, frequency, clinical characteristics, treatment strategies, and prognosis of neonatal arrhythmias in a tertiary pediatric cardiac center. We retrospectively reviewed neonates diagnosed with arrhythmia within the first 28 days of life at Basaksehir Cam and Sakura City Hospital between 1 January 2021 and 1 May 2025. Demographic data, electrocardiographic and echocardiographic findings, treatment modalities, recurrence, morbidity, and mortality were analyzed. Patients were categorized as having benign or non-benign arrhythmias. A total of 65 neonates (57% male, mean weight 3.2 kg) were included. Non-benign arrhythmias were more frequent (77%) compared to benign arrhythmias (23%). Supraventricular tachycardia (35%) was the most common non-benign arrhythmia, followed by long QT syndrome (10.7%) and complete atrioventricular block (9.2%). Antiarrhythmic therapy was required in 55% of patients. Pacemaker implantation was performed in seven infants with conduction disorders. Recurrence occurred in 3% of cases, exclusively among patients with supraventricular tachycardia. During a median follow-up of 12.8 months, no mortality was observed. Prenatal diagnosis and early management contribute to favorable outcomes, as reflected in the absence of mortality in this cohort. Larger, prospective studies are warranted to define optimal management strategies and treatment durations for neonatal arrhythmias.

Objectives: This study aimed to investigate the early effects of cigarette smoke exposure on endothelial function in healthy adolescents by analyzing blood endocan levels and urinary cotinine concentrations. A novel endocan/cotinine ratio was proposed to enhance the assessment of endothelial response to tobacco exposure. Methods: In this cross-sectional case-control study, 88 adolescents aged 13–18 years were recruited from Istanbul University between January and August 2021. Participants were divided into two groups: exposed (n=44) and non-exposed (n=44) to cigarette smoke. Blood endocan and urine cotinine levels were measured using ELISA. Statistical analysis included the Mann-Whitney U test and Spearman’s correlation. Results: Among the exposed participants, 11.4 % (n=5) were active smokers and 88.6 % (n=39) were passive smokers. Systolic blood pressure was significantly higher in the exposed group (p=0.03). Although endocan levels did not differ significantly between groups (p=0.74), median values were higher in the exposed group (1847.5 pg/mL, range: 14.79–3,121.63) compared to controls (1806.2 pg/mL, range: 116.83–4,618.90). Urinary cotinine levels were markedly elevated in the exposed group (p<0.001).Significant positive correlations were found between exposure duration (pack-years) and both endocan levels (r=0.318, p=0.01) and cotinine levels (r=0.524, p<0.001). A significant negative correlation was identified between cotinine and endocan levels specifically in the exposed group (r=−0.435, p=0.003), with regression analysis showing that each 1 ng/mL increase in urinary cotinine was associated with a 3.23 pg/mL reduction in serum endocan (R ² =0.189, p=0.003), suggesting that cotinine levels accounted for 18.9 % of the variability in endocan concentrations. No such correlation was observed in the control group (r=−0.015, p=0.925).The endocan/cotinine ratio showed a decreasing trend in the exposed group (median: 25.69, mean: 28.76 ± 21.45) compared to non-exposed participants (median: 34.24, mean: 47.31 ± 53.89), though this difference did not reach statistical significance (U=1,149.0, p=0.132). A negative correlation was found between BMI and endocan levels (r=−0.337, p=0.001), while a weak positive correlation was observed between age and cotinine concentration (r=0.222, p=0.038). Conclusions: Cigarette smoke exposure in adolescents leads to elevated cotinine levels and increased blood pressure (p=0.03), indicating early vascular changes. The observed negative correlation between cotinine and endocan levels (r=−0.435, p=0.003) may reflect a compensatory endothelial response. The endocan/cotinine ratio could serve as a novel, early biomarker for endothelial dysfunction in youth exposed to cigarette smoke.

Neonatal arrhythmias, though relatively uncommon, can range from benign self-limiting conditions to life-threatening disorders requiring intensive management. Data on their clinical spectrum, management, and outcomes remain limited. This study aimed to evaluate the types, frequency, clinical characteristics, treatment strategies, and prognosis of neonatal arrhythmias in a tertiary pediatric cardiac center. We retrospectively reviewed neonates diagnosed with arrhythmia within the first 28 days of life at Basaksehir Cam and Sakura City Hospital between January 1, 2021, and May 1, 2025. Demographic data, electrocardiographic and echocardiographic findings, treatment modalities, recurrence, morbidity, and mortality were analyzed. Patients were categorized as having benign or non-benign arrhythmias. 65 neonates (57% male, mean weight 3,2 kg) were included. Non-benign arrhythmias were more frequent (77%) compared to benign arrhythmias (23%). Supraventricular tachycardia (35%) was the most common non-benign arrhythmia, followed by long QT syndrome (10,7%) and complete atrioventricular block (9,2%). Antiarrhythmic therapy was required in 55% of patients. Pacemaker implantation was performed in seven infants with conduction disorders. Recurrence occurred in 3% of cases, exclusively among patients with supraventricular tachycardia. During a median follow-up of 12,8 months, no mortality was observed. Prenatal diagnosis and early management contribute to favorable outcomes, as reflected in the absence of mortality in this cohort. Larger, prospective studies are warranted to define optimal management strategies and treatment durations for neonatal arrhythmias.