The Real-World Utility of the LINQ Implantable Loop Recorder in Pediatric and Adult Congenital Heart Patients

Abstract

Objectives: This study sought to determine the practical use of the recently introduced LINQ implantable loop recorder (LINQ-ILR) in a cohort of pediatric and adult congenital arrhythmia patients.

Background: Correlating symptoms to a causative arrhythmia is a key aspect of diagnosis and management in clinical electrophysiology.

Methods: Retrospective review of clinical data, implantation indications, findings, and therapeutic decisions in patients who underwent LINQ-ILR implantation from April 1st, 2014 to January 30th, 2017 at Boston Children's Hospital.

Results: A total of 133 patients were included, of which 76 (57%) were male. The mean age at implantation was 15.7 ± 9.1 years with a duration of follow-up of 11.8 months. Congenital heart disease was present in 34 patients (26%), a confirmed genetic diagnosis in 50 (38%), and cardiomyopathy in 22 (26%), and the remainder were without a previous diagnosis. Syncope was the most common indication for LINQ-ILR implantation, occurring in 59 patients (44%). The median time to diagnosis was 4.5 months, occurring in 78 patients (59%). Cardiac device placement occurred in 17 patients (22%), a medication change in 9 (12%), electrophysiology study/ablation in 5 (6%), or LINQ-ILR explantation in 42 (54%). Infection or erosion occurred in 5 patients. Syncope was correlated with a diagnostic transmission (54% vs. 31%, p = 0.01).

Conclusions: The LINQ-ILR is an important diagnostic tool, providing useful data in more than one-half of patients in <6 months. Adverse events are low. Patient selection is critical and undiagnosed syncope represents an important presenting indication for which a LINQ-ILR implant should be considered.

Keywords: adult congenital; arrhythmias; loop recorder; pediatric.