Use of an implantable loop recorder in the evaluation of children with congenital heart disease

Usefulness of insertable cardiac monitors for risk stratification: current indications and clinical evidence

INTRODUCTION

The 2018 ESC Syncope guidelines expanded the indications for an insertable cardiac monitor (ICM) to patients with unexplained syncope and primary cardiomyopathy or inheritable arrhythmogenic disorders.

AREAS COVERED

This review article discusses the clinical evidence for using an ICM for risk stratification in different patient populations including Brugada syndrome, long QT syndrome, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, cardiac sarcoidosis, and congenital heart disease.

EXPERT OPINION

Clinical data on the usefulness of ICMs in different patient populations is limited but most studies demonstrate early detection of clinically relevant arrhythmias, such as nonsustained ventricular tachycardia or atrial fibrillation. It is important to emphasize that the study populations usually comprise selected populations where conventional diagnostic methods fail to clarify the mechanism of symptoms. The effect of an ICM on prognosis by earlier detection of arrhythmias is difficult to demonstrate in populations with rare disease. Risk stratification in patients with cardiomyopathy or inheritable arrhythmogenic disorders remains a niche indication for ICMs. The most important indication for an ICM remains unexplained syncope in patients at low risk of SCD. Given the device costs and uncertain clinical value of device-detected arrhythmias, it is unclear whether it is also useful in non-syncopal patients.

Diagnostic Efficacy of a Single-Lead Ambulatory 14-Day ECG Monitor in Symptomatic Children

Background

The CardioSTAT is a single-lead ambulatory electrocardiography monitor that has been validated for use in adult patients. Recording is made through 2 electrodes positioned in a lead-I configuration, and the device allows monitoring for 2, 7, or 14 days. We sought to investigate the efficacy of this device in children with paroxysmal palpitations.

Methods

In phase I, the quality of tracings from simultaneous CardioSTAT recordings and D1-lead recordings of a standard 12-lead electrocardiography machine in 23 children were compared. Phase II was a prospective observational cohort study comparing arrhythmia detection using the CardioSTAT vs currently used devices (24-hour Holter monitor and the Cardiomemo loop recorder) in 52 children complaining of palpitations.

Results

In Phase I, all but 3 rhythm strips were correctly identified. The pacing spikes on 3 strips were not adequately identified by the observers for the CardioSTAT recording. In Phase II, symptomatic episodes were reported in 42%, 73%, and 100% of subjects during monitoring with the Holter, Cardiomemo, and CardioSTATdevices, respectively. An abnormal rhythm was detected in 13%, 23%, and 35% of subjects by the Holter, Cardiomemo, and CardioSTAT monitors, respectively. The underlying rhythm during symptomatic events was determined in 90% of cases with the CardioSTAT monitor, whereas it was determined in only 19% and 29% of cases using the Holter and Cardiomemo monitors, respectively.

Conclusions

The CardioSTAT monitor provided good-quality tracings and was superior to the 24-hour Holter monitor and the Cardiomemo loop recorder in determining the presence or absence of pathologic arrhythmia in the study cohort.

Early detection of ventricular arrhythmias in adults with congenital heart disease using an insertable cardiac monitor (EDVA-CHD study)

BACKGROUND

Sudden cardiac death (SCD) due to ventricular arrhythmias (VA) is an important mode of death in adults with congenital heart disease (CHD). Risk stratification is difficult in this heterogeneous population. Insertable cardiac monitors (ICM) may be useful for risk stratification. The purpose of the present study was to evaluate the use of ICM for the detection of VA in adults with CHD.

METHODS

In this prospective single-center observational study we included consecutive adults with CHD deemed at risk of VA who received an ICM between March 2013 and February 2019. The decision to implant an ICM was made in a Heart Team consisting of a cardiac electrophysiologist and a cardiologist specialized in CHD.

RESULTS

A total of 30 patients (mean age, 38 ± 15 years; 50% male) received an ICM. During a median follow-up of 16 months, 8 patients (27%) had documented nonsustained VA. Of these 8 patients, 3 (10%) received a prophylactic ICD. Furthermore, ICM-detected arrhythmias were present in 22 patients (73%) leading to a change in clinical management in 16 patients (53%). Besides the patients receiving an ICD, 10 patients (33%) had a change in their antiarrhythmic drugs, 6 patients (20%) underwent an electrophysiology study, and 1 patient (3%) received a pacemaker.

CONCLUSIONS

The detection of VA by the ICM contributed to the clinical decision to implant a prophylactic ICD. Furthermore, ICM-detected arrhythmias led to important changes in the clinical management. Therefore, long-term arrhythmia monitoring by an ICM seems valuable for risk stratification in adults with CHD.

Value of implantable loop recorders in patients with structural or electrical heart disease

Purpose

In patients with structural heart disease (SHD) or inherited primary arrhythmia syndrome (IPAS), the occurrence of unexplained syncope or palpitations can be worrisome as they are at increased risk of sudden cardiac death. An implantable loop recorder (ILR) can be a useful diagnostic tool. Our purpose was to compare the diagnostic yield, arrhythmia mechanism, and management in patients with SHD, patients with IPAS, and those without heart disease.

Methods

Retrospective single-center study in consecutive patients who underwent an ILR implantation.

Results

Between March 2013 and December 2016, a total of 94 patients received an ILR (SHD, n = 20; IPAS, n = 14; no SHD/IPAS, n = 60). The type of symptoms at the time of implantation was similar between groups. During a median follow-up of 10 months, 45% had an ILR-guided diagnosis. Patients with IPAS had a lower diagnostic yield (14%) in comparison to the other groups (no SHD/IPAS 47%, P = 0.03; SHD 60%, P = 0.01, respectively). Furthermore, patients with SHD had a higher incidence of nonsustained VT in comparison to patients without SHD/IPAS (30 versus 3%, P < 0.01). ILR-guided therapy was comparable between groups. In the SHD group, a high proportion (10%) received an implantable cardioverter-defibrillator; however, this was not statistically significantly higher than the other groups (no SHD/IPAS 3%, IPAS 0%, P = 0.08).

Conclusions

In comparison to patients without heart disease, the diagnostic yield of an ILR was lower in patients with IPAS and the prevalence of ILR-diagnosed nonsustained VT was higher in patients with SHD.

PocketECG: A New Noninvasive Method for Continuous and Real-Time ECG Monitoring-Initial Results in Children and Adolescents

Long-term ECG is widely used in diagnosis and assessment of many cardiac symptoms which may be caused by dangerous arrhythmias that sometimes can be difficult to document. The PocketECG system is a new technological solution for a long-term, noninvasive, continuous and real-time ECG monitoring that provides automatic diagnosis of dysrhythmias. ECG data transmission occurs over a mobile network. The goal of this study was to assess the reliability of long-term ECG recordings acquired with the PocketECG system. One hundred and fifteen patients (43 girls and 72 boys) of an average age of 15.5 ± 2.5 years were examined at the Department of Cardiology at the Children's Memorial Health Institute. Two simultaneous 24-h ECG recordings were conducted: one with a Holter monitor and one with the PocketECG system. A linear correlation was demonstrated between the two methods with regard to the recorded QRS complexes [H = 1173.0 (-1946.40; 4838.50) + PocketECG*0.98 (0.94; 1.02)]. Mean diurnal heart rhythms were comparable (p > 0.05) despite the fact that the slowest and the fastest rates were different. The rate of detection for ventricular, supraventricular dysrhythmias and pauses in ventricular rhythm were comparable in both methods. The PocketECG system for continuous and real-time ECG recording is a reliable method for the assessment of heart rhythm and dysrhythmias in children and adolescents.

Holter Monitoring and Loop Recorders: From Research to Clinical Practice

Holter monitors are tools of proven efficacy in diagnosing and monitoring cardiac arrhythmias. Despite the fact their use is widely prescribed by general practitioners, little is known about their evolving role in the management of patients with cryptogenic stroke, paroxysmal atrial fibrillation, unexplained recurrent syncope and risk stratification in implantable cardioverter defibrillator or pacemaker candidates. New Holter monitoring technologies and loop recorders allow prolonged monitoring of heart rhythm for periods from a few days to several months, making it possible to detect infrequent arrhythmias in patients of all ages. This review discusses the advances in this area of arrhythmology and how Holter monitors have improved the clinical management of patients with suspected cardiac rhythm diseases.

Minimally invasive approach to the child with palpitations

Palpitations are a common reason for referral to a pediatric cardiologist. Although generally benign, palpitations are a significant cause for concern in the individual and their family. Similarly, palpitations may be the initial presentation of significant heart disease, resulting in heightened concern in the referring physician. Although emphasis is usually placed on excluding arrhythmia as the cause for palpitations, there are a variety of noncardiac causes for palpitations. The patient history and physical examination are the key components of the evaluation and guide subsequent investigations. In many cases, an immediate diagnosis cannot be made and additional testing may be required; this often includes further monitoring for episodes, cardiac imaging and ambulatory monitoring. Current technologies for ambulatory monitoring during symptoms include Holter monitoring and a variety of patient-activated event recorders, including implantable loop recorders. Each presents its own unique advantages and disadvantages to aid diagnosis in the management of a child with palpitations. The primary focus for the clinician is to determine whether the etiology is benign in nature or whether there is underlying heart disease that may carry a more serious prognosis.

A retrospective study of the clinical experience of the implantable loop recorder in a paediatric setting

The implantable loop recorder (ILR) has proved highly efficacious in the management of syncope, presyncope and palpitations in selected populations. Limited information regarding patient selection and diagnostic yield exists in the paediatric setting. A retrospective evaluation of patients who underwent ILR implantation over a 66-month period, in a tertiary paediatric cardiology unit was conducted. Twenty-three patients (10 male, 13 female) following initial assessment and investigation, were referred for device implantation. The mean age at time of ILR insertion was 11.39 +/- 4.34 (range, 2.0-16.8) years. The indications for ILR were recurrent syncope (n = 11), presyncope (n = 3) or palpitations (n = 9). Four (17.4%) patients had structural heart disease, three (13%) had a positive family history of sudden cardiac death and one (4%) had perinatal arrhythmia. One patient required ILR repositioning, and pocket infection necessitated explantation in one further patient. Minimum follow-up was 7.8 months during which symptoms were reported in 15 (65.2%) patients post-ILR insertion. Eight (34.7%) remained asymptomatic. Of the 15 who experienced symptom recurrence, eight (53.3%) had an arrhythmia recorded. Tachycardias recorded were polymorphic ventricular tachycardia (n = 1) and supraventricular tachycardia (n = 5). Clinically significant bradycardias documented, included sinus arrest (n = 1) and Mobitz type II second degree atrioventricular block (n = 1). The ILR had a high diagnostic yield, enabling an arrhythmic or non-arrhythmic diagnosis in 65.2% of patients with recurrent syncope, presyncope or palpitations in a selected paediatric population.

The challenge of diagnosing arrhythmogenic right ventricular cardiomyopathy in the young

We report two cases of arrhythmogenic right ventricular cardiomyopathy (ARVC) in the pediatric age group. In both cases, the diagnosis was considered and pursued but would not be made utilizing Task Force Criteria. The diagnosis was made based on the morphology of a single beat during exercise testing. We illustrate the difficulty of diagnosing ARVC in the young even with a heightened index of suspicion.

The diagnostic yield from implantable loop recorders in children and young adults

BACKGROUND

Syncope and palpitations occur frequently in young patients. Noninvasive diagnostic testing may be inconclusive.

AIM

To assess the diagnostic yield of implantable loop recorders in young patients.

PATIENTS AND METHODS

Thirty-three young patients underwent implantation of a loop recorder for long-term monitoring of cardiac rhythm, to establish symptom-rhythm correlation. They belonged to one of three subgroups: those with structurally normal heart, normal electrocardiogram at rest, and negative family history (n = 16); patients with structural heart disease and previous surgical repair (n = 11), and patients with proven or suspected primary electrical disease (n = 6). A combination of automatic and patient-activated recordings was used to monitor cardiac rhythm during symptomatic episodes.

RESULTS

There were no procedural complications. Diagnostic electrograms could be obtained in all patients. A high degree of symptom-rhythm correlation was established. In 8/33 patients, no recurrence of symptoms was observed either until end of battery life of the device (n = 4) or until last follow-up (n = 2). Specific cardiac therapy was required, based on rhythms recorded by the device in 15 patients (until last follow-up). This consisted of catheter ablation of a tachyarrhythmia (n = 7), pacemaker implantation or upgrade (n = 5) or ICD implantation (n = 5). In the remaining patients (n = 10), recurrence of symptoms was associated with a normal electrocardiogram, and in two of these patients a non-cardiac diagnosis was made.

CONCLUSIONS

In selected patients, the implantable loop recorder provides valuable diagnostic information to guide further therapy.

Use of the implantable loop recorder in children and adolescents

INTRODUCTION

Recurrent but infrequent syncopes represent a diagnostic challenge, since they frequently remain unexplained despite extensive investigations. This applies specifically for patients who carry an increased risk of potentially lifethreatening arrhythmias, either due to congenital cardiac disease or primary electrical disorders. Implantable loop recorders permit long-term electrocardiographic monitoring. Experience with these devices is still limited in children.

PATIENTS AND METHODS

Between January 1999 and August 2005, 12 patients underwent implantation of a loop recorder in our tertiary referral centre. The mean age was 10.9 years, with a range from 2 to 17 years. Of the patients, 6 had structural disease, 3 had primary electrical abnormalities, and 3 had no cardiovascular disease.

RESULTS

Resyncope occured in 9 of the 12 patients. Arrhythmic origin of the syncope was diagnosed in 4 of these patients. The events recorded were ventricular fibrillation in 2, intermittent asystole in 1, and pacemaker-syndrome in the other patient. Malignant arrhythmia was ruled out in the remaining 5 patients. There were no complications related to implantation of the loop recorder, and the mean duration until explantation was 8.3 months.

CONCLUSIONS

Based on our experience, we suggest that implantation of a loop recorder represents an additional tool for a selected group of children. Due to its invasive nature, it should be restricted to patients at high risk, or those in which there is substantial clinical suspicion of the likelihood of serious arrhythmias when conventional testing has been inconclusive. In this cohort, implantation of the loop recorder either helps to establish the correct diagnosis, or to exclude an arrhythmic event, thus avoiding unnecessary escalation of therapy and providing reassurance for the family.

The clinical impact of implantable loop recorders in patients with syncope

AIMS

Implantable loop recorders (ILR) provide an opportunity to record ECG data from a spontaneous syncopal event. We conducted a randomized study to investigate the impact of the Reveal Plus ILR on an unselected population of patients with recurrent syncope. Initial follow-up (at least 6 months) did not demonstrate a reduction in syncopal events or an improvement in quality of life. We report the planned extension of follow-up to 18 months.

METHODS AND RESULTS

All patients presenting acutely with recurrent unexplained syncope over a 16-month period, following a basic clinical work-up, were randomized to receive the ILR or conventional investigation and management. A total of 421 patients presented, 201 were eligible, median age 74, (IQ range 61-81) 54% female, with median syncopes 3 (IQ range 2-6). Median follow-up 17 months (IQ range 9-23). 42 (43%) of ILR patients and 8 (6%) of conventional patients received an ECG diagnosis (hazard ratio 6.53, 95% CI 3.73-11.4, P<0.001). Time to second syncope was significantly longer for ILR patients, although of borderline significance (P=0.04). A greater variety of diagnoses and treatments were seen in ILR patients. ILR patients had fewer post-randomization investigations and fewer days in hospital; however, cost savings were not statistically significant. There was improved quality of life in the ILR group (visual analogue scales, P=0.03) for general wellbeing. Overall mortality was 12% with no difference between the two groups.

CONCLUSION

Investigation by the ILR significantly increases the diagnostic rate and ECG directed treatments in a typical unselected syncopal population. Long-term follow-up has demonstrated a significant subsequent reduction in syncopal events with improved quality of life.

Implantable loop recorders detect tachyarrhythmias in symptomatic patients with negative electrophysiological studies

BACKGROUND

Implantable loop recorders (ILR) are a valuable tool in the investigation of syncope and compare favourably with non-invasive and intracardiac electrophysiological assessment of bradycardia. They are known to detect tachyarrhythmias but have not been shown to add to the diagnostic yield of electrophysiological testing in symptomatic patients.

METHODS

We prospectively studied the first 41 patients (aged 48+/-19 years) in whom ILR were used at our institution after negative electrophysiological studies (EPS). All patients were symptomatic with palpitations (11), syncope (22) or both (8). Nine patients had known structural heart disease (two ischaemic, four cardiomyopathy, two valvular and one congenital). Patients were assessed according to demographic factors, symptoms and investigations. Loop recordings were analysed and assessed according to conventional criteria.

RESULTS

Among 41 patients in whom electrophysiological studies had failed to demonstrate arrhythmias, six were found to have clinically significant tachyarrhythmias (four ventricular and two supraventricular).

CONCLUSION

ILR diagnose prognostically significant tachyarrhythmias in symptomatic patients with negative electrophysiological studies.

Catecholaminergic polymorphic ventricular tachycardia detected by an insertable loop recorder in a pediatric patient with exercise syncopal episodes

Syncope is a common clinical problem that occurs at all ages and is particularly prevalent in childhood and adolescence. The evaluation of syncope is best approached using the history and physical examination, electrocardiogram and risk stratification to guide further diagnostic tests. Syncope associated with exercise or exertion must be considered dangerous, it can be a predictor of sudden cardiac death and therefore it must be taken seriously. The insertable loop recorder has been proven to be useful in the diagnosis of recurrent syncope in adult patients in whom the cause of the syncope cannot be found by other noninvasive means. We report the first known case of cathecolaminergic polymorphic ventricular tachycardia detected by an insertable loop recorder in a 5-year-old boy with a syncopal history and no structural heart disease.

Feasibility of the Inframammary Location for Insertable Loop Recorders in Young Women and Girls

The parasternal location for the insertable loop recorder (ILR) has potential for erosion in small patients, and can be aesthetically unappealing, especially for young women. We assessed the feasibility of the inframammary location in nine patients, utilizing a 2 cm transverse incision at the inferior and medial border of the left or right breast. Signal quality was adequate with clearly discernable atrial and ventricular electrograms. No complications involving the surgical site were observed. Cosmetically, placement of the scar in the natural breast crease has been favorably accepted. Inframammary implantation of the ILR is feasible, and is the preferred method in young women and girls at our center.

Efficacy of implantable loop recorders in establishing symptom-rhythm correlation in young patients with syncope and palpitations

OBJECTIVE

To evaluate efficacy of the recently introduced implantable loop recorder (ILR) in establishing symptom-rhythm correlation in young patients with syncope, near syncope, palpitations, and acute life-threatening events (ALTEs).

METHODS

A retrospective study was conducted with patients with ILR from 3 pediatric centers. Inclusion criteria were age <or=25 years and a minimum follow-up of 1 month. All ILR-stored events were analyzed regularly for the presence or absence of an arrhythmia at the time of the symptomatic event.

RESULTS

Twenty-one patients (12 male, 9 female) with an average age of 12.3 +/- 5.3 years (range: 0.8-22 years) were included in the study. Five (24%) patients had structural heart disease, 2 (10%) had a family history of sudden cardiac death, 3 (14%) had QT prolongation on electrocardiogram, and 11 had no cardiovascular disease. Indications for ILR were recurrent syncope and near syncope (n = 15), palpitations (n = 2), and ALTE (n = 2). Fourteen (67%) patients continued to have symptoms, and 7 (33%) had no symptoms after ILR over a follow-up period of 8.4 +/- 4.7 months (range: 1.9-16 months). Symptom-rhythm correlation was possible in all 14 patients who continued to have symptoms (supraventricular tachycardia in 4, ventricular tachycardia in 2, torsades de points in 1, asystole in 1, junctional bradycardia in 1, and sinus rhythm in 5).

CONCLUSIONS

ILR is useful in determining the presence or absence of an arrhythmia during symptoms of syncope, near syncope, and palpitations as well as ALTEs in patients with and without structural heart disease when conventional diagnostic testing, such as electrocardiogram, Holter monitoring, and/or external loop recording, is inconclusive.

Electronic medical devices: a primer for pathologists

CONTEXT

Electronic medical devices (EMDs) with downloadable memories, such as implantable cardiac pacemakers, defibrillators, drug pumps, insulin pumps, and glucose monitors, are now an integral part of routine medical practice in the United States, and functional organ replacements, such as the artificial heart, pancreas, and retina, will most likely become commonplace in the near future. Often, EMDs end up in the hands of the pathologist as a surgical specimen or at autopsy. No established guidelines for systematic examination and reporting or comprehensive reviews of EMDs currently exist for the pathologist.

OBJECTIVE

To provide pathologists with a general overview of EMDs, including a brief history; epidemiology; essential technical aspects, indications, contraindications, and complications of selected devices; potential applications in pathology; relevant government regulations; and suggested examination and reporting guidelines.

DATA SOURCES

Articles indexed on PubMed of the National Library of Medicine, various medical and history of medicine textbooks, US Food and Drug Administration publications and product information, and specifications provided by device manufacturers.

STUDY SELECTION

Studies were selected on the basis of relevance to the study objectives.

DATA EXTRACTION

Descriptive data were selected by the author.

DATA SYNTHESIS

Suggested examination and reporting guidelines for EMDs received as surgical specimens and retrieved at autopsy.

CONCLUSIONS

Electronic medical devices received as surgical specimens and retrieved at autopsy are increasing in number and level of sophistication. They should be systematically examined and reported, should have electronic memories downloaded when indicated, will help pathologists answer more questions with greater certainty, and should become an integral part of the formal knowledge base, research focus, training, and practice of pathology.