Role of new generation implantable loop recorders in managing undiagnosed pediatric cardiac symptoms
Authors: Agudo-Montore Pedro , Stuart Graham , Wilson Deirdre , Spentzou Georgia , Sidiqqui Rabeea , González-Corcia Cecilia 
Published: August 2024

Pediatric cardiac symptoms such as palpitations, syncope, or seizure-like episodes pose diagnostic challenges for general pediatricians. These symptoms, though often benign, may reveal underlying arrhythmias or inherited cardiac conditions (ICCs), affecting the quality of life and limiting activity participation. The purpose of this study is to determine the effectiveness and safety of implantable loop recorders (ILRs) in diagnosing and managing arrhythmias in pediatric patients. A retrospective cohort study conducted over an 8-year period from January 2016 to December 2023 in a single pediatric cardiology center. A cohort of 155 pediatric patients (median age 11.4 years) who underwent ILR implantation were selected based on symptoms such as palpitations, chest pain, or syncope, and those with previously recorded arrhythmias or high-risk ICCs. The primary outcomes were the diagnostic yield of ILRs for arrhythmias and subsequent changes in patient management. Diagnostic yield was defined as the detection of relevant arrhythmias, such as pauses of 3 s or longer, high-degree AV block, sinus node dysfunction, supraventricular tachycardia, ventricular tachycardia, or inappropriate sinus tachycardia. The median follow-up period was 2.3 years (845 days). Diagnostic arrhythmias were recorded in 60% of patients with symptom-activated transmissions and 80% of device-activated transmissions. Sinus pauses (37.5%) and VT (30%) were the most common arrhythmias detected. In patients with syncope (n = 76), 30% had relevant arrhythmias. In the palpitations group (n = 20), 35% had relevant arrhythmias. Approximately 80% of patients with ILR-diagnosed arrhythmias underwent targeted management, including medication changes and additional procedures. No significant complications were observed; minor complications occurred in 2.5% of patients.

Conclusions: New generation ILRs are effective and safe for diagnosing and managing pediatric arrhythmias, providing significant reassurance to patients and families. Further studies are needed to evaluate the impact of ILRs on quality of life and sports participation in high-risk young patients.

What is Known:• Pediatric Cardiac Symptoms: Symptoms like palpitations, syncope, and seizure-like episodes in pediatric patients pose significant diagnostic challenges.• Diagnostic Tools: Traditional diagnostic tools such as ECG, Holter monitors, and external loop recorders often have low diagnostic yields due to the sporadic nature of symptoms.• Implantable Loop Recorders (ILRs): ILRs have been shown to improve the diagnostic yield for arrhythmias in adults and provide long-term rhythm monitoring.

What is New:• Effectiveness in Pediatrics: This study demonstrates that new generation ILRs significantly enhance the diagnostic yield for arrhythmias in pediatric patients with undiagnosed cardiac symptoms.• Safety and Efficacy: The study confirms that ILRs are both safe and effective in the pediatric population, with minimal complications and high diagnostic accuracy.• Targeted Management: Findings show that ILR-diagnosed arrhythmias lead to targeted management changes in approximately 80% of cases, including medication adjustments and additional procedures.• Long-term Monitoring: ILRs provide continuous long-term monitoring, offering reassurance to patients and families, and potentially improving quality of life and participation in activities for high-risk young patients.