Interstage Monitoring Using an Implantable Loop Recorder: A Pilot Study

The primary objective of this investigation is to evaluate the feasibility and safety of implantable loop recorder implantation (using the LUX-DX™) in newborns undergoing stage 1 palliation. The secondary objective of the investigation is to evaluate the feasibility of continuous measurement of heart rate and arrhythmia using an implantable loop recorder (LUX-Dx™) during the interstage period.

An implantable loop recorder will be placed at the time of chest closure following stage 1 palliation (either at the time of index surgery or delayed). The device will be placed in a subclavicular pouch through the existing sternotomy incision. Participants will be in the study for 6 months to 3 years.

Study Overview

• Status: Completed
• Conditions: Univentricular Heart
• Intervention / Treatment: Device: LUX-Dx™

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Early Phase 1

Contacts and Locations

Study Locations

• United States
  • Massachusetts
    • Boston, Massachusetts, United States, 02115
      • Boston Children's Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: No older than 1 month (Child)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients with single ventricle physiology undergoing stage 1 palliation in the 1st month of life

Exclusion Criteria:

• Prematurity (<36 weeks gestational age)
• Birth weight <2.5 kg
• Hybrid stage 1 palliation (patent ductus arteriosus stenting, bilateral pulmonary artery bands)
• Presence and/or need for devices sensitive to magnetic fields such as hearing aids, pacemaker, and other implanted devices.
• Clinical team does not think that the patient is a good candidate

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Device Feasibility
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of patients with successful ILR implantation at the time of surgery	Feasibility of ILR implantation	At the time of stage 1 surgery, typically the first week of life
Number of patients with ILR related complication (any of: infection, erosion, device migration, foreign body rejection phenomena, formation of hematomas or seromas, local tissue reaction and/or tissue damage	Safety of ILR implantation	Between the stage 1 and stage 2 surgery, typically until 4-6 months of age

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of patient who completed >70% planned ILR transmissions		Between the stage 1 and stage 2 surgery, typically until 4-6 months of age
Number of patients with arrhythmias	Any arrhythmia, including supraventricular tachycardia, junctional ectopic tachycardia, ventricular tachycardia, atrioventricular block, pause >2.5 seconds	Between the stage 1 and stage 2 surgery, typically until 4-6 months of age
Number of patients with interstage complication	Any complication, including unplanned emergency department visit, unscheduled hospital admission, unscheduled intensive care unit admission, arrhythmias, major interstage intervention, minor interstage intervention, cardiac arrest, death	Between the stage 1 and stage 2 surgery, typically until 4-6 months of age
Complications at the time of ILR removal	Defined as easily removed, removed with difficulty, removed with complication	At stage 2 or 3 palliation, typically between 4 months and 4 years of age

Collaborators and Investigators

• Sponsor: Boston Children's Hospital

Study record dates

Study Major Dates

• Study Start (Actual): March 15, 2023
• Primary Completion (Actual): December 30, 2025
• Study Completion (Actual): December 30, 2025

Study Registration Dates

• First Submitted: February 3, 2023
• First Submitted That Met QC Criteria: February 15, 2023
• First Posted (Actual): February 27, 2023

Study Record Updates

• Last Update Posted (Actual): May 19, 2026
• Last Update Submitted That Met QC Criteria: May 18, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Heart Diseases; Congenital Abnormalities; Cardiovascular Abnormalities; Heart Defects, Congenital; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Univentricular Heart
• Other Study ID Numbers: IRB-P00044387

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes