Introduction: The aim of this study was to describe our experience and outcome of ablation therapy of arrhythmias in children at a tertiary care center. Methods: Data was collected retrospectively from the hospital medical records. All children presenting to AUBMC between 2000 and 2020 who underwent cardiac ablation were included. The data collected included type of arrhythmia, ablation technique, age and weight at ablation, procedure complications, medications used, and outcome assessment. Results: We had 67 patients who underwent cardiac ablation. Of those, 60% were males with a mean age of 15 years. Structural heart disease was present in 6% of patients. Wolff-Parkinson-White syndrome (WPW) was most prevalent at 31%, followed by atrioventricular nodal reentrant tachycardia (AVNRT) at 24%, atrioventricular reentrant tachycardia (AVRT) at 19%, ventricular tachycardia (VT) at 10%, atrial fibrillation (AF) at 2%, and atrial tachycardia (AT) at 1%. The remaining 13% of patients presented with less common types of arrhythmias, including narrow complex tachycardia, retrograde dual atrioventricular nodal reentry, premature ventricular contractions (PVC), and orthodromic reciprocating tachycardia. Antiarrhythmic medications were started prior to the procedure in 59% of our population. Medication regimens post-ablation included beta blockers (68%), type 1c antiarrhythmics (25%), calcium channel blockers (3%), ivabradine (2%), and amiodarone (2%). The completed procedures showed a success rate of 93%. Conclusion: Ablation of arrhythmias in children is an effective procedure in the treatment of childhood arrhythmias. More studies are needed on cardiac ablation in children with structural heart disease in the Middle East region.

Background: Left bundle branch area pacing (LBBAP) offers physiological pacing with potential advantages over right ventricular (RV) pacing, particularly in children. However, data on LBBAP in pediatric populations are scarce. Objective: This study aimed to assess the feasibility and safety of LBBAP in children by reporting 6 cases done successfully. Methods: Six children (four males, two females), aged 2 to 16 years, underwent LBBAP between December 2022 and January 2024 at the American Univeristy of Beirut Medical Center (AUBMC). The implantation procedure followed established techniques. Baseline characteristics, echocardiographic measurements, and pacing parameters were recorded. Results: All six cases fulfilled the criteria for LBBAP. Successful LBBAP was achieved in all cases. Median weight is 20.5 kg, with three patients under 5 years old. Baseline left ventricular ejection fraction (LVEF) was normal in 4 cases, with two exhibiting 52%. The interventricular septal thickness averaged 4.5 mm. No major complications were encountered during follow-up. Conclusion: Left bundle branch area pacing might be a promising alternative to conventional RV pacing, offering potential advantages over traditional pacing methods. Further research is needed to fully elucidate its efficacy and long-term benefits in pediatric populations.

Background: Acquired QT-prolongation in children undergoing treatment for acute lymphoblastic leukemia (ALL) is potentially fatal. To date specific recommendations for ECG monitoring during ALL treatment are lacking. Aim: We aimed to assess the prevalence of QT prolongation and explore possible causes in ALL patients undergoing therapy. Methods and Results: A retrospective review of the records of all pediatric ALL patients treated between 2018-2021 at the American University of Beirut was conducted. Patients lacking complete ECG records, baseline ECGs, or those with structural or functional heart disease were excluded from the study. QT interval was measured manually, and the longest measurement was chosen. Bazett’s formula was used to correct for heart rate. All medications, the patient was on at the time of the ECG recording were documented. In addition, the level of electrolytes measured within the preceding 24 hrs of the ECG were analyzed. 28 out of 257 ECGs met prolonged QTcB criteria (≥450 ms or ≥60 ms increase from baseline). Using multivariate analysis, age, cyclophosphamide, fluconazole, and voriconazole maintained their significant association with QTcB prolongation. Hypomagnesemia and hypocalcemia showed association with QTc prolongation by bivariate analysis; however, this association could not be confirmed using Multivariate analysis due to the small sample size. The association between ondansetron and trimethoprim/sulfamethoxazole (TMP-SMX) could not be determined as all patients were receiving those two medications. Importantly, life-threatening Ventricular arrhythmias, Torsade de pointes, did not occur in any of our patients. Conclusion: Our study provides insights into factors contributing to QTcB prolongation, including specific medications, chemotherapeutic agents and possibly hypomagnesemia and hypocalcemia. To better understand these associations, larger prospective studies are necessary. In the interim, it is essential to conduct frequent follow-ups with ECGs when using these medications.

Introduction: QT interval represents the ventricular depolarization and repolarization. Its accurate measurement is critical since prolonged QT can lead to sudden cardiac death. QT is affected by heart rate and is corrected to QTc via several formulae. QTc is commonly calculated on the ECG and not the 24-hour Holter. Methods: 100 patients presenting to our institution were evaluated by an ECG followed by a 24-hour Holter. QTc measurement on both of these platforms using Bazett and Fridreicia formulae was recorded and compared. Results: Mean age was 14.09 years, with the majority being males. Mean heart rate was 125.87. In the ECG, the mean QTc interval via Bazett formula was 0.40 seconds compared to 0.38 seconds using the Fridreicia formula. The mean corrected QT via Bazett formula was 0.45, 0.39 and 0.42 seconds for the shortest RR, longest RR and the average RR respectively. In contrast to Fridreicia formula, the corrected QT interval was 0.40, 0.39, and 0.40 seconds for the shortest RR, longest RR and the average RR respectively. Using Bazett, highest specificity reached during longest RR interval (92.2%) while highest sensitivity was recorded during shortest RR interval (40%). As for Fridreicia, sensitivity always reached 0% while highest specificity was reached during average RR interval. Conclusion: QTc measured during Holter ECG reached a high specificity regardless of RR interval using the Fridreicia and during long and average RR interval for Bazett formula. The consistently low sensitivity reveals that Holter ECG should not be used to rule out prolonged QT.