Missing LINQ: extrusion of a new-generation implantable loop recorder in a child

The Evolving Role of Insertable Cardiac Monitors in Patients with Congenital Heart Disease

Insertable cardiac monitors (ICMs) have been used more frequently and in a wider variety of circumstances in recent years. ICMs are used for symptom-rhythm correlation when patients have potentially arrhythmogenic syncope and for less traditional reasons such as rhythm surveillance in patients with genetic arrhythmia syndromes or other diseases with high arrhythmia risk. ICMs have good diagnostic yield in pediatric patients and in adults with congenital heart disease and have a low rate of complications. Implantation techniques should take patient-specific factors into account to optimize diagnostic yield and minimize risk.

Novel Technique for Cardiac Monitor Implantation in Pediatrics

Implantable cardiac monitors (ICM) allow for symptom-rhythm correlation. Current manufacturer recommendations call for implantation of ICMs diagonally in the left anterior chest. Complications such as skin tenting and device erosion have occurred using this technique in pediatric patients. The purpose of this study was to assess the safety and efficacy of implanting ICMs via new vertical-parasternal technique (VP) compared to manufacturer-recommended diagonal technique (D) in pediatric patients. Single-center, IRB-approved retrospective study of pediatric patients that underwent ICM implantation from 01/01/2017 to 12/01/2021. All implants were performed after informed consent, under sterile conditions in the electrophysiology laboratory. Data collected included demographics, implant orientation (VP or D), complications, device type, presence of P-wave, and measurement of R-wave amplitude at implantation and follow-up. ICMs were implanted in 34 patients without congenital heart disease. Initial R-wave amplitude average for VP 1.00, D 0.99 (p = NS). Follow-up R-wave amplitude was 0.97 VP and 0.93 for D (p = NS). Median follow-up period for VP was 11 and for D was 20 months (p = NS). D cohort had only post-procedural complication due to skin tenting of the ICM in child < 2.5 years of age. No skin tenting, erosions, or complications occurred in the vertical-parasternal implant technique. Vertical-Parasternal ICM implantation is as safe and effective as the manufacturer-recommended diagonal implant. Short- and long-term data demonstrate an equivalent R-wave detection and no significant signal deterioration, even in very young children. No skin tenting, erosions, or complications occurred in the vertical parasternal implant technique.

Continuous Arrhythmia Monitoring in Pediatric and Adult Patients With Left Ventricular Noncompaction

Patients with left ventricular noncompaction (LVNC) are at risk of clinically significant arrhythmias and sudden death. We evaluated whether implantable loop recorders could detect significant arrhythmias that might be missed in these patients during annual Holter monitoring. Selected pediatric and adult patients with LVNC who consented to implantable loop recorder placement were monitored for 3 years (study duration, 10 April 2014-9 December 2019). Fourteen subjects were included (age range, 6.5-36.4 yr; 8 males). Of 13 patients who remained after one device extrusion, one underwent implantable cardioverter-defibrillator placement. Four patients (31%) had significant arrhythmias: atrial tachycardia (n=2), nonsustained ventricular tachycardia (n=1), and atrial fibrillation (n=1). All 4 events were clinically asymptomatic and not associated with left ventricular ejection fraction. In addition, a high frequency of benign arrhythmic patterns was detected. Implantable loop recorders enable continuous, long-term detection of important subclinical arrhythmias in selected patients who have LVNC. These devices may prove to be most valuable in patients who have LVNC and moderate or greater ventricular dysfunction.

Outcomes of Implantable Loop Monitoring in Patients <21 Years of Age

Rhythm-symptom correlation in pediatric patients with syncope/palpitations or at risk cohorts can be difficult, but important given potential associations with treatable or malignant arrhythmia. We sought to evaluate the use, efficacy and outcomes of implantable loop recorders (ILR) in pediatrics. We conducted a retrospective study of pediatric patients (<21 years) with implanted ILR. Patient/historical characteristics and ILR indication were obtained. Outcomes including symptom documentation, arrhythmia detection and ILR based changes in medical care were identified. Comparison of outcomes were performed based on implant indication. Additional sub-analyses were performed in syncope-indication patients comparing those with and without changes in clinical management. A total of 116 patients with ILR implant were identified (79 syncope/37 other). Symptoms were documented 58% of patients (syncope 68% vs nonsyncope 35%; p = 0.002). A total of 37% of patients had a documented clinically significant arrhythmia and 25% of patients had a resultant change in clinical management independent of implant indication. Arrhythmia type was dependent on implant indication with nonsyncope patients having more ventricular arrhythmias. Pacemaker/defibrillator implantation and mediation management were the majority of the clinical changes. In conclusion, IRL utilization in selected pediatric populations is associated with high efficacy and supports clinical management. ILR efficacy is similar regardless of indication although patients with nonsyncope indications had a higher frequency of ventricular arrhythmias as opposed to asystole and heart block in syncope indications. The majority of arrhythmic findings occurred in the first 12 months, and new technology that would allow for less invasive monitoring for 6 to 12 months may be of value.

Un-LINQed: Spontaneous extrusion of newer generation implantable loop recorders

Background

Insertable cardiac monitors (ICMs) are often used for long-term monitoring of cardiac rhythm. The Medtronic’s LINQ Reveal ™ is a new generation wireless, automated, and patient responsive subcutaneous ECG monitoring device. Despite several advantages to its small size we have noted an unusually high incidence of extrusion at our center.

Methods

& Results: We conducted a retrospective case analysis to review Reveal LINQs implanted at our center. All devices were inserted using the provided insertion tools. Patients with extruded devices were identified and details regarding the site and technique of insertion, incision closure, use of peri-operative antibiotics, and follow-up details were collected. 81 patients underwent 85 Reveal LINQ implants at a tertiary care University Hospital referral center. The most common reason for implant was suspected arrhythmia with or without structural heart disease or unexplained syncope. There were 4 spontaneous extrusions occurring within 7–24 days after insertion with an incidence rate of 4.7%. One extruded device was anchored to subcutaneous tissue, and no pocket/device infections or hematomas were noted.

Conclusions

Device migration and erosion through skin are important potential adverse events for the Reveal LINQ implantable loop recorder. This study reports an unexpectedly high rate of extrusion without infection. The authors suggest that the depth of the incision is the main factor impacting extrusions. Larger studies are recommended, however, and a proposed measure to avoid spontaneous extrusion is the design of a longer manufacturer’s blade in order to increase the depth of the incision and insertion.

Placement of Reveal LINQ Device in the Left Anterior Axillary Position

Implantable loop recorders (ILR) are utilized for long-term rhythm monitoring. Typical placement of the Medtronic Reveal LINQ along the left parasternal border may compromise the quality and/or feasibility of future imaging studies. We sought to evaluate the utility of placing an ILR in the left anterior axillary position and the impact on the quality of cardiac imaging. We reviewed patients from May 2017 to June 2018 who had placement of a Reveal LINQ device in the left anterior axillary position. Demographic, procedural, and clinical data were collected via retrospective review. Cardiac magnetic resonance imaging (MRI) studies were reviewed for image quality after ILR placement. Eight patients met inclusion criteria for this study (median age 6 years, 50% female). Six patients (75%) had an ILR placed in the operating room, while all others were placed in the electrophysiology lab. All patients demonstrated acceptable R waves for diagnostic evaluation (median = 0.85 mV, range 0.24-1.7 mV). Cardiac MRI was obtained in 7 patients following ILR placement with diagnostic image quality and no adverse events. One device was explanted 28 days after placement due to concern for possible infection. No other devices required removal or revision (median follow up duration 11 months, IQR 8-13.5). ILR placement in the left anterior axillary position can record adequate signals in pediatric patients. In addition, axillary ILR device position may allow for completion of cardiac imaging, particularly cardiac MRI, without significant artifacts which is critical for patients with congenital heart disease.

The Case of the Migrating Loop Recorder

The role of ambulatory electrocardiographic monitoring has changed considerably in recent years with the increased use of implantable loop recorders with their shrinking size. With an excellent safety profile from previous studies, their use is generally seen as a low-risk procedure. Despite this, unexpected complications can occur, including unexpected migration. (Level of Difficulty: Intermediate.)

Detection of arrhythmias in adult congenital heart disease patients with LINQTM implantable loop recorder

BACKGROUND

Rhythm disorders are the leading cause of morbidity and mortality in adults with congenital heart disease (ACHD). Infrequent or asymptomatic arrhythmias may not be detected by routine monitoring. Implantable loop recorders (ILRs), such as the Reveal LINQ^TM , have been useful in long-term monitoring for arrhythmias in adults with cryptogenic stroke.

OBJECTIVE

We propose the Reveal LINQ^TM will detect arrhythmias, not documented by other monitoring modalities, resulting in change in management in ACHD patients.

METHODS

This is a single center retrospective review of Reveal LINQ^TM use in ACHD patients from 2014-2017. Medical records were reviewed to determine cardiac diagnosis, indication for implant, ILR findings, and changes in management.

RESULTS

Twenty-two patients, median age 25 years, underwent ILR implantation. ILR findings resulted in change in management in nine (41%) patients. One-third (3/9) of the patients with clinically relevant events were asymptomatic. Patients with Fontan palliation had the highest number of pertinent positive events (57%). ACHD physiologic class D patients were more likely to have a positive finding (P = .034) compared to other physiologic classes. Majority (75%) of patients with positive events had arrhythmias documented on ILR which were not demonstrated on prior Holter/event monitors. Pertinent negative event occurred in one patient with Fontan palliation (5%) who had syncope corresponding to sinus rhythm.

CONCLUSION

ILRs are a useful adjunct for arrhythmia monitoring in the ACHD population with clinically relevant events in 41% of patients. A special consideration for ILRs could be made for high-risk asymptomatic patients.

Reveal LINQ Versus Reveal XT Implantable Loop Recorders: Intra- and Post-Procedural Comparison

OBJECTIVES

To compare the procedure, recovery, hospitalization times, and costs along with patient/parent satisfaction after newer-generation cardiac implantable loop recorder (Reveal LINQ; Medtronic Inc, Minneapolis, Minnesota) and previous-generation implantable loop recorder (Reveal XT; Medtronic Inc).

STUDY DESIGN

A prospective study of patients undergoing LINQ implantations between April 2014 and October 2015 was performed. Retrospective chart review of patients undergoing XT implantations was performed for comparison.

RESULTS

Thirty-one patients received LINQ and 15 patients received XT. Indications included syncope/palpitations (28/46, 61%), history of arrhythmias (9/46, 20%), arrhythmia burden in congenital heart disease (5/46, 10%), and monitoring in channelopathies (4/46, 9%). The LINQ group underwent more conscious sedation procedures than the XT group (8/31 vs 0/15, P = .04) with shorter procedural time (9 vs 34 minutes, P <.001), room occupation time (38 vs 81 minutes, P <.001), recovery time (21 vs 67 minutes, P <.001), and total hospital time (214 vs 264 minutes, P = .046). The LINQ group also had shorter return to activity time (2 vs 5 days, P = 1). Three device erosions in the LINQ group required reintervention. The LINQ group had fewer body image issues than the XT group (1/26 vs 5/14, P = .01) with both groups scoring 5/5 overall patient/parent satisfaction score at follow-up. Both groups had comparable total direct hospital costs (US $5905 vs $5438, P = .8).

CONCLUSIONS

LINQ offers better procedural and recovery time compared with XT. LINQ implantations under conscious sedation reduce total hospitalization time.