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

Diagnostic yield of ambulatory cardiac monitoring in pediatric patients with palpitations

Background

Palpitations are a frequent reason for referral to pediatric cardiology providers and diagnostic workup includes ambulatory cardiac monitoring. While common practice, the diagnostic yield is unknown in the pediatric population. The objective is to evaluate the diagnostic yield of 24-h Holter and extended ambulatory cardiac monitoring in pediatric patients with palpitations.

Methods and Results

All pediatric patients aged 10-18 years who had ambulatory cardiac monitoring (1-30 days) through the Pocket Electrocardiogram (PocketECG™) system (Medi-Lynx) between January 2016 and July 2020 were included. Patients with an International Classification of Diseases-10 diagnosis code of palpitations (R00.2) during enrollment were evaluated separately. Tachyarrhythmia diagnoses included atrial fibrillation (AF), nonsustained supraventricular tachycardia (nSVT), supraventricular tachycardia (SVT), nonsustained ventricular tachycardia (nVT), and ventricular tachycardia (VT). Age, heart rates, arrhythmia type, and symptomatic transmission data were collected and analyzed. A total of 2388 patients (mean age 11.6 years, 58% F) with the R00.2 code had ambulatory cardiac monitoring (28% 24-h Holter, 72% extended) performed during the study period and there were 6287 total patients (mean age 13.9 years, 54% F) that underwent ambulatory cardiac monitoring (42% 24-h Holter, 58% extended) during that time. Of 2388 patients, 321 (13%) were diagnosed with tachyarrhythmia: AF (9), nSVT (192), SVT (59), and nVT (61). In the overall cohort, 764 (12%) patients were diagnosed with tachyarrhythmia: AF (22), nSVT (478), SVT (85), nVT (177), and VT (2). Symptomatic transmissions with normal cardiac rhythm were common in the R00.2 (n = 1697, 71%) and overall (n = 3848, 61%) groups. No episodes of nSVT, SVT, nVT, or VT were associated with symptomatic transmissions.

Conclusion

Ambulatory cardiac monitors are an integral part of the diagnostic workup for pediatric palpitations patients and have demonstrated a high yield of combined positive arrhythmia diagnoses and symptomatic normal transmissions. Further prospective study of this population with the integration of clinical information is warranted.

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.

Implantable Loop Recorder with Long Sensing Vector: Safety, Acceptability, and Sensing Performance in Pediatric Patients

Implantable loop recorders (ILRs) are effective tools for detecting arrhythmias by long-term continuous heart rhythm monitoring. Benefits have been demonstrated even in pediatric patients. ILR with a long sensing vector has recently been designed to improve signal quality in terms of P wave visibility and R wave amplitude. However, there are no data on its use in pediatric patients. We considered a series of pediatric patients implanted with a long sensing vector ILR. Sensing performance, including R wave amplitude and P wave visibility, device-related complications, and diagnostic yield were collected. During follow-up, each patient guided by his/her parents/guardians was also asked to complete a brief questionnaire to assess patient acceptability of the device. Twenty-five consecutive pediatric patients (mean age 11.3 ± 3.5 years, 72% male) were enrolled. The insertion success rate was 100% on the first attempt with no complications. The median amplitude of the R wave was 1.15 mV (interquartile range, 1.01-1.42) with no significant differences between patients aged ≤ or > 10 years (p = 0.726) and between female and male (p = 0.483). P wave was classified as 'always visible' in 24/25 patients (96%). ILR was generally well accepted and tolerated by all involved patients. During a median follow-up of 297 days (117-317), we achieved in 5 patients a correlation between symptoms and rhythm disorders (20%) and ruled out significant arrhythmias in 6 symptomatic children (24%). Long sensing vector ILR showed to be well accepted, with good signal quality and an excellent safety profile even in pediatric patients.

Impact of Device Miniaturization on Insertable Cardiac Monitor Use in the Pediatric Population: An Analysis of the MarketScan Commercial and Medicaid Databases

Background

Insertable cardiac monitors (ICMs) are effective in the detection of paroxysmal arrhythmias. In 2014, the first miniaturized ICM was introduced with a less invasive implant technique. The impact of this technology on ICM use in pediatric patients has not been evaluated. We hypothesized an increase in annual pediatric ICM implants starting in 2014 attributable to device miniaturization.

Methods and Results

A retrospective observational study was conducted using administrative claims from MarketScan Medicaid and commercial insurance claims databases. Use of ICM between January 2013 and December 2018 was measured (normalized to the total enrolled population ≤18 years) and compared with balancing measures (Holter ambulatory monitors, cardiac event monitors, encounters with syncope diagnosis, implantation of implantable cardioverter‐defibrillator/pacemaker). Secondary analyses included evaluations of subsequent interventions and complications. The study cohort included 33 532 185 individual subjects, of which 769 (0.002%) underwent ICM implantation. Subjects who underwent ICM implantation were 52% male sex, with a median age of 16 years (interquartile range, 10–17 years). A history of syncope was present in 71%, palpitations in 43%, and congenital heart disease in 28%. Following release of the miniaturized ICM, use of ICMs increased from 5 procedures per million enrollees in 2013 to 11 per million between 2015 and 2018 (P<0.001), while balancing measures remained static. Of 394 subjects with ≥1 year of follow‐up after implantation, interventions included catheter ablation in 24 (6%), pacemaker implantation in 15 (4%), and implantable cardioverter‐defibrillator implantation in 7 (2%).

Conclusions

Introduction of the miniaturized ICM was followed by a rapid increase in pediatric use. The effects on outcomes and value deserve further attention.

The Role of External Loop Recorders in Arrhythmia-Related Symptoms in Children: A Single Center Experience

In this study, we report our experience with the use of external loop recorders (ELRs), in terms of diagnostic efficiency according to symptoms and symptom-rhythm correlation in pediatric patients. We evaluated ELRs applied to 178 patients between April 2017 and November 2020 at our center. The mean age of 172 patients included in the study was 13.6 ± 3.8 years, and 69.8% were female. ELR indications were palpitations in 98 (56.9%) cases, chest pain and palpitations in 43 (25%) cases, presyncope/syncope in 28 (16.2%) cases, and pacemaker/ implantable cardioverter-defibrillator (ICD) problems in 3 (0.2%) cases. ELR recording times were 14.2 ± 9.7 days on average, ranging from 2 to 67 days. While the symptom-rhythm correlation was 29.1% in total, when the indications were evaluated one by one, this correlation was found to be 30.2% in palpitations, 34.7% in chest pain and palpitations, and 10.7% in presyncope/syncope. The total diagnostic efficiency was 68.1%. In the follow-up of ELR cases, a total of 139 (80.8%) patients received clinical follow-up without medication, 15 (8.8%) patients received medical treatment, and 18 (10.4%) patients underwent EPS. The cardiac ELR system is useful in detecting underlying arrhythmias. Demonstrating sinus tachycardia at the time of the symptom may be seen as negative finding, but while experiencing symptoms, it is diagnostically valuable and may help avoid further investigation with costly and invasive diagnostic procedures. For diagnostic efficiency and cost effectiveness, the optimal recording time is 2 weeks, but it should be extended to 4 weeks in cases such as of presyncope/syncope that cannot be explained with a 2-week ELR use.

The evidence for the implantable loop recorder in patients with inherited arrhythmia syndromes: a review of the literature

Risk stratification of patients with inherited arrhythmia syndromes (IASs) can be challenging. Recent guidelines acknowledge a place for considering the implantable loop recorder (ILR) to outrule malignant arrhythmia as a cause of syncope in certain inherited arrhythmia patients who are at low risk of sudden cardiac death. In this comprehensive literature review, we evaluate the available evidence for the use of the ILR in the IASs and in relatives of victims of sudden arrhythmic death syndrome.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Developed in collaboration with and endorsed by the Heart Rhythm Society (HRS), the American College of Cardiology (ACC), the American Heart Association (AHA), and the Association for European Paediatric and Congenital Cardiology (AEPC) Endorsed by the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS)

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

2021 PACES expert consensus statement on the indications and management of cardiovascular implantable electronic devices in pediatric patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consenus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology, (ACC) and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate follow-up in pediatric patients.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Executive Summary

Guidelines for the implantation of cardiac implantable electronic devices (CIEDs) have evolved since publication of the initial ACC/AHA pacemaker guidelines in 1984 [1]. CIEDs have evolved to include novel forms of cardiac pacing, the development of implantable cardioverter defibrillators (ICDs) and the introduction of devices for long term monitoring of heart rhythm and other physiologic parameters. In view of the increasing complexity of both devices and patients, practice guidelines, by necessity, have become increasingly specific. In 2018, the ACC/AHA/HRS published Guidelines on the Evaluation and Management of Patients with Bradycardia and Cardiac Conduction Delay [2], which were specific recommendations for patients >18 years of age. This age-specific threshold was established in view of the differing indications for CIEDs in young patients as well as size-specific technology factors. Therefore, the following document was developed to update and further delineate indications for the use and management of CIEDs in pediatric patients, defined as ≤21 years of age, with recognition that there is often overlap in the care of patents between 18 and 21 years of age.

This document is an abbreviated expert consensus statement (ECS) intended to focus primarily on the indications for CIEDs in the setting of specific disease/diagnostic categories. This document will also provide guidance regarding the management of lead systems and follow-up evaluation for pediatric patients with CIEDs. The recommendations are presented in an abbreviated modular format, with each section including the complete table of recommendations along with a brief synopsis of supportive text and select references to provide some context for the recommendations. This document is not intended to provide an exhaustive discussion of the basis for each of the recommendations, which are further addressed in the comprehensive PACES-CIED document [3], with further data easily accessible in electronic searches or textbooks.

Diagnostic Accuracy and Safety of Confirm Rx™ Insertable Cardiac Monitor in Pediatric Patients

Insertable cardiac monitors (ICM) are subcutaneously implanted devices that monitor a patient's heart rate and rhythm (Rossano in Pediatrics 112(3):e228, 2003). The diagnostic accuracy and safety of the Confirm Rx^TM (Abbott, Minneapolis, MN) ICM in pediatric patients is unknown. This is a single center, retrospective, IRB-approved review of patients ≤ 21 years implanted with Confirm Rx^TM ICMs from 2017 to 2020. Data collected included demographics, indications, presence of P-wave and R-wave amplitude at implantation and follow-up, number/appropriateness of transmissions pre and post implementation of SharpSense^TM technology, reprogramming to improve accuracy, time from implantation to arrhythmia detection, and complications. There were 29 patients (median age: 8 years, 59% females). P-waves were identified in all patients and average R-wave amplitude was 0.85 mV (0.26-1.03 mV). There was no significant difference in R-wave amplitude based on size (BSA ≥ 1.5 m²: 0.76 mV, < 1.5 m²: 0.91 mV) or congenital heart disease (+CHD: 0.86 mV, -CHD: 0.85 mV). Arrhythmias identified were the following: wide complex tachycardia (1), supraventricular tachycardia (4), bradycardia/sinus pause (3), and premature ventricular contraction (1). SharpSense^TM implementation decreased the false-positive rate in device-initiated transmissions (55.4% to 0%, p < 0.00001). Average time from implantation to arrhythmia detection was 2.63 months (range: 0-8.8). A single complication of cellulitis occurred. Confirm Rx^TM is appropriate for implant in pediatric patients regardless of age, BSA, or CHD. Implementation of SharpSense™ technology dramatically decreased the false-positive rate. Follow-up studies could utilize additional monitoring devices to provide analysis on potential events that the Confirm Rx^TM ICM missed.

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

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.

Ventricular tachycardia recorded in a competitive swimmer using Confirm Rx™ loop recorder

Conventional ambulatory heart rhythm monitoring is limited in its ability to provide rapid diagnosis of arrhythmias in athletes participating in water or high-intensity sports. This case report is of a 17-year-old female competitive swimmer who underwent loop recorder implantation with Confirm Rx™ ICM 3500 (Abbott, Minneapolis, MN) to monitor for arrhythmias during swimming. The purpose of this case report is to describe the utility of implantable loop recorders in arrhythmia diagnosis and symptom evaluation in water sport athletes.

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.

Pediatric Disorders of Orthostatic Intolerance

Orthostatic intolerance (OI), having difficulty tolerating an upright posture because of symptoms or signs that abate when returned to supine, is common in pediatrics. For example, ∼40% of people faint during their lives, half of whom faint during adolescence, and the peak age for first faint is 15 years. Because of this, we describe the most common forms of OI in pediatrics and distinguish between chronic and acute OI. These common forms of OI include initial orthostatic hypotension (which is a frequently seen benign condition in youngsters), true orthostatic hypotension (both neurogenic and nonneurogenic), vasovagal syncope, and postural tachycardia syndrome. We also describe the influences of chronic bed rest and rapid weight loss as aggravating factors and causes of OI. Presenting signs and symptoms are discussed as well as patient evaluation and testing modalities. Putative causes of OI, such as gravitational and exercise deconditioning, immune-mediated disease, mast cell activation, and central hypovolemia, are described as well as frequent comorbidities, such as joint hypermobility, anxiety, and gastrointestinal issues. The medical management of OI is considered, which includes both nonpharmacologic and pharmacologic approaches. Finally, we discuss the prognosis and long-term implications of OI and indicate future directions for research and patient management.

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.

Neurological Complications of Cardiac Disease

This article focuses on the complex interactions between the cardiovascular and neurologic systems. Initially, we focus on neurological complications in children with congenital heart disease both secondary to the underlying cardiac disease and complications of interventions. We later discuss diagnosis and management of common syncope syndromes with emphasis on vasovagal syncope. We also review the diagnosis, classification, and management of children and adolescents with postural orthostatic tachycardia syndrome. Lastly, we discuss long QT syndrome and sudden unexpected death in epilepsy (SUDEP), reviewing advances in genetics and current knowledge of pathophysiology of these conditions. This article attempts to provide an overview of these disorders with focus on pathophysiology, advances in molecular genetics, and current medical interventions.

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

Cardiac rhythm monitoring has been facilitated by the use of implantable loop recorders. New models of these devices are 87% smaller than before allowing for easier implantation and use in the paediatric population. Recommendations are for closure with adhesive. We report a device extrusion in a 6-year-old patient. Based on this, our practice has changed to include subcutaneous sutures this complication.

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.

Arrhythmia Detection in Pediatric Patients: ECG Quality and Diagnostic Yield of a Patient-Triggered Einthoven Lead-I Event Recorder (Zenicor EKG-2™)

Symptoms that may be caused by arrhythmia are common in pediatric outpatient departments, though it remains challenging to reveal paroxysmal tachycardia. This investigation evaluated prospectively the quality and diagnostic yield of a newly available handheld patient-activated event recorder (ER) in children. In 226 children (pts) aged 0-17 years with or without congenital heart defects, pacemaker/ICDs or arrhythmia, a lead-I ER ECG was created. ER ECGs were recorded by pressing the patients' thumbs on the device and were analyzed in comparison with a lead-12 ECG, as gold standard. Event recording and data transmission were possible in all cases. ECG quality of the ER showed a high accordance in measuring heart rate (ICC = 0.962), duration of QRS complexes (κ = 0.686), and PR interval (ICC = 0.750) (p < 0.001) although P wave detection remained challenging (p = 0.120). 36 % (n = 82) of the pts had heart rhythm disturbances. The ER yielded 92 % sensitivity in diagnosing supraventricular tachycardia plus 77 % sensitivity and 92 % specificity in identifying abnormal ECGs. In children, the application of the tested ER was suitable. ECGs of good quality could be performed and transmitted easily, and also complex arrhythmia analysis was possible. This ER is an excellent diagnostic device for the detection and exclusion of tachycardia in children.

Using a Cardiac Event Recorder in Children with Potentially Arrhythmia-Related Symptoms

BACKGROUND

In this study, we reported our experience with the use of cardiac event recorders in pediatric patients.

METHODS

We evaluated 583 patients fitted with an event recorder (15-30 days) between March 2010 and November 2014 at our clinic. Excluded from the study were 117 patients with no recorded events and six with records contaminated by electrocardiogram artifacts. All of the patients received electrocardiograms, Holter monitoring, and echocardiography before the cardiac event recording.

RESULTS

The patient sample consisted of 460 patients (64% female). The mean age was 12.8 ± 4.1 years. The median number of recorded events was 7. The indications included palpitations in 336 (73%) patients, syncope in 27 (6%) patients, and chest pain and palpitations in 97 (21%) patients. Whereas 64 patients (14%) had structural heart disease according to echocardiographic examination, the remaining patients had normal echocardiographic examination results. The most frequent cardiac comorbidities were mitral valve prolapse (6%), operated tetralogy of Fallot (1.5%), and complicated congenital heart diseases with single ventricle physiology (1%). The recorded events were sinus tachycardia in 113 (25%) patients, supraventricular tachycardia in 35 (8%) patients, ventricular extrasystole in 20 (4%) patients, supraventricular extrasystole in nine (2%) patients, and ventricular tachycardia in two (0.4%) patients. Based on the event recorder and follow-up electrocardiogram findings, 46 patients received an electrophysiology study/ablation. The symptom-rhythm correlation was 39%.

CONCLUSION

In the presence of possible arrhythmia-related symptoms in children, a cardiac event recorder can be considered a useful primary diagnostic method. More research on this topic is needed.

Palpitations and Arrhythmias and Sudden Cardiac Arrest/Sudden Cardiac Death in Children and Adolescents

Palpitations are a common complaint, particularly in teenagers, with etiologies ranging from no detectable cardiac dysrhythmia to life-threatening dysrhythmias. Despite the fact that as many as 50% of children and adolescents may be asymptomatic prior to experiencing sudden cardiac arrest, the occurrence of palpitations may afford the opportunity to detect a potentially lethal arrhythmia condition. This article discusses the evaluation of palpitations in the pediatric population by focusing on the two most common life-threatening arrhythmia diagnoses that may initially manifest itself in the pediatric population with the chief complaint of palpitations-Wolff-Parkinson-White syndrome and the long QT syndrome.

How to Practice Sports Cardiology: A Cardiology Perspective

The rigorous cardiovascular (CV) demands of sport, combined with training-related cardiac adaptations, render the athlete a truly unique CV patient and sports cardiology a truly unique discipline. Cardiologists are advised to adopt a systematic approach to the CV evaluation of athletes, taking into consideration the individual sports culture, sports-specific CV demands, CV adaptations and their appearance on cardiac testing, any existing or potential interaction of the heart with the internal and external sports environment, short- and long-term CV risks, and potential effect of performance-enhancing agents and antidoping regulations. This article outlines the systematic approach, provides a detailed example, and outlines contemporary sports cardiology core competencies.

Evaluation rhythm problems in unexplained syncope etiology with implantable loop recorder

BACKGROUND

Syncope is a frequent complaint in children and adolescents and may be a significant sign of serious pathology. Although patient history, family history, and physical examination are sufficient to reach a diagnosis in most cases of syncope, the cause of syncope still cannot be determined after initial investigation in one-third to half of all patients. The aim of this study was to evaluate the diagnostic yield of implantable loop recorder (ILR) in children with unexplained syncope.

METHODS

A retrospective review was carried out of clinical data, indications, findings, and a final management strategy in patients who underwent ILR implantation.

RESULTS

A total of 12 patients with a mean age of 9.4 ± 4.5 years underwent ILR (Reveal Plus; Medtronic) implantation. ILR implantation indication was syncope in all of the patients. Family history, routine cardiac assessment, including resting 12-lead electrocardiogram, transthoracic echocardiography, 24 h Holter recording, and event recorder findings, were normal with the exception of one patient with (previously corrected) tetralogy of Fallot. After an average of 20 months (range, 1-36 months), six patients developed symptoms. ILR memory showed torsades de pointes-ventricular fibrillation (n = 3), catecholaminergic polymorphic ventricular tachycardia (n = 1), asystole and ventricular tachycardia (n = 1), and normal sinus rhythm (n = 1). At the time of writing six patients were still in follow up with no symptoms after an average of 25.2 months.

CONCLUSION

Implantable loop recorder plays an important role in the diagnosis of life-threatening arrhythmias in which syncope is otherwise unexplained. ILR implantation should be remembered in children whose symptoms are strongly correlated with rhythm disturbances.

The teenager with palpitations

Palpitations can result from cardiac awareness (increased conscious perception of the heart beating) or from a fast or irregular cardiac rhythm. Most causes for palpitations in the teenager can be diagnosed with minimal testing. Patients with an abnormal ECG, non-sinus tachycardia, abnormal cardiac examination, concerning family history, or palpitations associated with activity or syncope should be referred to a pediatric cardiologist. This article discusses the evaluation, testing, and management of teenagers with palpitations. It also provides a general guideline for referral for subspecialty evaluation.

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.

Common syndromes of orthostatic intolerance

The autonomic nervous system, adequate blood volume, and intact skeletal and respiratory muscle pumps are essential components for rapid cardiovascular adjustments to upright posture (orthostasis). Patients lacking sufficient blood volume or having defective sympathetic adrenergic vasoconstriction develop orthostatic hypotension (OH), prohibiting effective upright activities. OH is one form of orthostatic intolerance (OI) defined by signs, such as hypotension, and symptoms, such as lightheadedness, that occur when upright and are relieved by recumbence. Mild OI is commonly experienced during intercurrent illnesses and when standing up rapidly. The latter is denoted "initial OH" and represents a normal cardiovascular adjustment to the blood volume shifts during standing. Some people experience episodic acute OI, such as postural vasovagal syncope (fainting), or chronic OI, such as postural tachycardia syndrome, which can significantly reduce quality of life. The lifetime incidence of ≥1 fainting episodes is ∼40%. For the most part, these episodes are benign and self-limited, although frequent syncope episodes can be debilitating, and injury may occur from sudden falls. In this article, mechanisms for OI having components of adrenergic hypofunction, adrenergic hyperfunction, hyperpnea, and regional blood volume redistribution are discussed. Therapeutic strategies to cope with OI are proposed.

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 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.

Digital implantable loop recorders in the investigation of syncope in children: Benefits and limitations

BACKGROUND

Conventional diagnostic methods for detecting arrhythmogenic causes of syncope in children are poor. Digital implantable loop recorders are of proven value in adults.

OBJECTIVES

The purpose of this study was to evaluate digital implantable loop recorders in the investigation of syncope in children.

METHODS

We reviewed the clinical and technical records of 18 consecutive patients (6 female and 12 male; age <or=16 years) who received an implantable loop recorder from 1999 to 2005.

RESULTS

Median age at implantation was 11.3 years (range 4.6-16.5 years). Median duration of the device in situ was 18 months (range 5-36 months). Median time to diagnosis was 6 months (range 1 day to 17 months). Two patients had a congenital heart defect. Ten children (56%) had an event, 9 (50%) of whom had diagnostic information; 5 (28%) had profound bradycardia or asystole; 2 (11%) had polymorphic ventricular tachycardia (VT); and 1 child had supraventricular tachycardia. One patient died, but the automatically activated recording was recorded over again after death. One child had sinus rhythm during syncope. One child with polymorphic VT had no auto-activation on two occasions, and the third activation was triggered by asystole after VT terminated. Sixteen patients (89%) had false-positive activations as a result of either artifact or sinus tachycardia.

CONCLUSION

The digital implantable loop recorder is a useful diagnostic modality in children with unexplained syncope. However, the automatic detection algorithm is imperfect, missing genuine polymorphic VT and frequently interpreting muscle tremors as VT. Because of continuous overwriting by automatic detection, genuine arrhythmias may be over-recorded by artifact.

Abdominal Implantation of Loop Recorders in Infants and Children

Implantable loop recorders have an important role in establishing symptom-rhythm correlation in adults with recurrent syncope or palpitations. The standard location of these devices is in a subcutaneous prepectoral pocket. As the device is bulky, this is not an ideal location in young patients. We report a technique of abdominal implantation of this device in 10 consecutive infants and children, achieving an excellent cosmetic result and diagnostic-quality electrograms at follow-up.

Evaluation of the child with an arrhythmia

Several recent technologic innovations will expand the therapeutic alternatives available to children with arrhythmia. Despite these advances, the management of these patients still requires a solid foundation of clinical skill and judgment. The primary care pediatric practitioner is often the first one to recognize the symptoms and signs of an arrhythmia. Careful assessment of the history, physical examination, and electrocardiogram is necessary for making the correct diagnosis.

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.

Advances in pediatric electrophysiology

PURPOSE OF REVIEW

The pediatric electrophysiology literature during the past year has addressed several topics that are particularly relevant for children and other patients with congenital heart disease. This paper reviews selected studies germane to physicians and health care personnel who treat pediatric and adult congenital heart patients with arrhythmias and electrophysiologic disorders.

RECENT FINDINGS

Advances in arrhythmia diagnostics have been reported in pediatrics using loop monitoring, both external and implanted. Diagnostic criteria and risk stratification strategies have been refined for the congenital and inherited rhythm disorders such as cardiomyopathies and long QT syndrome. The use of therapeutic procedures such as catheter ablation for complex arrhythmias in congenital heart disease is discussed. Finally, a summary of articles on implanted devices in pediatrics and congenital heart disease is reviewed, including implantable defibrillators, atrial antitachycardia pacemakers, and cardiac resynchronization therapy in pediatrics.

SUMMARY

Pediatric electrophysiology is a rapidly changing field, with advances seen in diagnostic evaluation of arrhythmia, refinement of risk-stratification testing, and therapeutic options such as catheter ablation and cardiac rhythm management devices. The evolution of pediatric electrophysiology from a diagnostic specialty into a therapeutic and interventional subspecialty has advanced the treatment options for children with cardiac arrhythmias and conduction disorders.