Qureshi, M. Yasir

Background: Coronary artery (CA) injury from catheter ablation is an uncommon complication, but the risk is under recognized. In pediatrics, CA imaging to assess for CA proximity is not commonly performed prior to ablation. The risk for CA injury significantly increases when a CA is within 3 mm of the site of ablation. Research Question: How often is there a CA within 3 mm of a potential ablation site in pediatric patients? Methods: A retrospective review of all coronary computed tomography angiograms (CTAs) in pediatric patients <18 years of age at Mayo Clinic from 2017 through 2023 was conducted. The proximity of CAs to potential ablation sites in the coronary sinus and the appendage bases were measured. Results: Seventy-two CTAs in 67 patients >15 kg and <18 years old were included. Median age was 12 years and median weight was 41 kg. In right dominant CA circulation, 23/36 (64%) had a CA within 3 mm of the coronary sinus. For those within 3 mm, the mean distance from the coronary sinus was 1.4 mm +/- 0.2 mm for a length of 10 mm +/- 2 mm (Figure 1A). In left and co-dominant CA circulation, 26/26 (100%) had a CA within 3 mm of the coronary sinus with a mean distance of 1.1 mm +/- 0.2 mm for a length of 27 mm +/- 2 mm (Figure 1B). The right CA was within 3 mm of the appendage base in 49/69 (71%). For those within 3 mm, the mean distance was 1.9 mm +/- 0.2 mm for a length of 17 mm +/- 2 mm. The circumflex CA was within 3 mm of the appendage base in 50/68 (74%). Of the 50 within 3 mm, the mean distance was 2.1 mm +/- 0.2 mm for a length of 9 mm +/- 2 mm. Conclusion: Most pediatric patients have a CA ≤ 3 mm from potential ablation sites in the coronary sinus and base of the appendages. Before performing catheter ablation in these areas, precautions should be taken to avoid CA damage.

Solitary myofibromas are rare, benign, mesenchymal tumors typically found in the head and neck regions. We report an exceptionally rare case of a solitary cardiac myofibroma and its short-term management and outcome. A two-month-old infant was referred due to a murmur. Echocardiography revealed a 2 × 1 cm solitary mass originating from a mitral papillary muscle, causing severe regurgitation. Magnetic resonance imaging showed the mass to be homogeneous on T1, hyperintense on T2, and hypointense on first-pass perfusion imaging with no enhancement on delayed postcontrast imaging. The mass was surgically excised partially due to its involvement with the mitral valve. Postoperative recovery was uneventful, with echocardiography four months later showing no tumor recurrence and trivial mitral regurgitation. This report provides valuable imaging and pathology examples to aid in the recognition of this rare tumor and demonstrates that successful surgical excision is possible, even with significant cardiac involvement.

Cardiac ventricular pressure overload affects patients with congenital heart defects and can cause cardiac insufficiency. Grafts of stem cell–derived cardiomyocytes are proposed as a complementary treatment to surgical repair of the cardiac defect, aiming to support ventricular function. Here, we report successful engraftment of human induced pluripotent stem cell–derived cardiac lineage cells into the heart of immunosuppressed rhesus macaques with a novel surgical model of right ventricular pressure overload. The human troponin+ grafts were detected in low-dose (2 × 10 6 cells/kg) and high-dose (10 × 10 6 cells/kg) treatment groups up to 12 weeks post-injection. Transplanted cells integrated and progressively matched the organization of the surrounding host myocardium. Ventricular tachycardia occurred in five out of 16 animals receiving cells, with episodes of incessant tachycardia observed in two animals; ventricular tachycardia events resolved within 19 days. Our results demonstrate that grafted cardiomyocytes mature and integrate into the myocardium of nonhuman primates modeling right ventricular pressure overload.

ABSTRACTNoonan syndrome (NS) is a predominantly autosomal dominant condition with various cardiac and extra‐cardiac manifestations. Although it has been linked with atrial arrhythmias, ventricular arrhythmias are extremely rare in the absence of underlying structural cardiac abnormalities. We report an instance of aborted sudden cardiac arrest in a 7‐year‐old male with a confirmed SOS1 variant and a lack of evidence to support a structural cardiac, metabolic, or infectious etiology. This is the second reported instance of sudden cardiac arrest related to ventricular fibrillation in a child with SOS1‐related NS in the absence of any structural cardiac defects. Although no definitive correlation can be ascertained from a limited existing body of knowledge surrounding SOS1 and ventricular fibrillation unrelated to structural heart defects, it provokes the idea of an arrhythmia phenotype and future research is warranted to guide proper clinical treatment, monitoring, and management of such individuals.

Aortic dissection is often a fatal condition if not recognized and treated emergently. Fortunately, it is extremely rare in children and adolescents. We report a case of an adolescent boy who survived an aortic dissection due to severe aortic root dilation. A comprehensive history and physical examination, including family history, can facilitate an early diagnosis of connective tissue diseases, such as Loeys-Dietz syndrome (LDS).

Background There is currently no consensus regarding the use of surveillance cross-sectional imaging in pediatric patients after bidirectional cavopulmonary connection (BDCPC). We sought to determine how computed tomography with angiography (CTA) and cardiac magnetic resonance (CMR) imaging impacted the clinical management of pediatric patients after BDCPC. Methods A single-center retrospective study including patients with single ventricle who had BDCPC between 2010 and 2019, and CTA/CMR studies obtained in these patients, at ≤5 years of age, and with Glenn physiology. Repeat studies on the same patient were included if the clinical situation had changed. The impact of CTA/CMR studies was categorized as major, minor, or none. Results Twenty-four patients (63% male) and 30 imaging studies (22 CTAs) were included. 60% were obtained in patients with hypoplastic left heart syndrome (HLHS); most common indication was Follow-up after an intervention (23%). 6 CMRs were performed on stable HLHS patients as part of a research protocol, with no clinical concerns. The overall impact of CTA/CMR studies was major in 13 cases (43.3%). CTA/CMR studies performed ≥1 year of age (62.5% vs 21.4%, P = .02) and in non-HLHS patients (66.7% vs 27.8%, P = .035) were associated with major impact. Also, 2/6 Research studies were associated with a major impact. Conclusions CTA/CMR imaging in pediatric patients with SV after BDCPC was associated with significant clinical impact in over 40% of cases, with a higher impact if obtained in patients ≥1 year of age and in non-HLHS patients. We cannot disregard the possibility of CMR as a surveillance imaging modality in this population.