Inappropriate ICD Discharges in Single-Chamber Versus Dual-Chamber Devices in the Pediatric and Young Adult Population

ACC/AHA/ASE/HFSA/HRS/SCAI/SCCT/SCMR 2025 Appropriate Use Criteria for Implantable Cardioverter-Defibrillators, Cardiac Resynchronization Therapy, and Pacing

This appropriate use criteria (AUC) document is developed by the American College of Cardiology along with key specialty and subspecialty societies. It provides a comprehensive review of common clinical scenarios where implantable cardioverter-defibrillator (ICD), cardiac resynchronization therapy (CRT), cardiac contractility modulation, leadless pacing, and conduction system pacing therapies are frequently considered. The 335 clinical scenarios covered in this document address ICD indications including those related to secondary prevention, primary prevention, comorbidities, generator replacement at elective replacement indicator, dual-chamber, and totally subcutaneous ICDs, as well as device indications related to CRT, conduction system pacing, leadless pacing, cardiac contractility modulation, and ICD therapy in the setting of left ventricular assist devices (LVADs).

The indications (clinical scenarios) were derived from common applications or anticipated uses, as well as from current clinical practice guidelines and results of studies examining device implantation. The indications in this document were developed by a multidisciplinary writing group and scored by a separate independent rating panel on a scale of 1 to 9 to designate care that is considered “Appropriate” (median 7 to 9), “May Be Appropriate” (median 4 to 6), and “Rarely Appropriate” (median 1 to 3). The final ratings reflect the median score of the 17 rating panel members.

In general, Appropriate designations were assigned to scenarios for which clinical trial evidence and/or clinical experience was available that supported device implantation. In contrast, scenarios for which clinical trial evidence was limited or device implantation seemed reasonable for extenuating or practical reasons were categorized as May Be Appropriate. Scenarios for which there were data showing harm, or no data were available, and medical judgment deemed device therapy was illadvised were categorized as Rarely Appropriate. For example, comorbidities including reduced life expectancy related to noncardiac conditions or severe cognitive dysfunction would negatively impact appropriateness ratings.

The appropriate use criteria for ICD, CRT, and pacing have the potential to enhance clinician decision making, healthcare delivery, and payment policy. Furthermore, recognition of clinical scenarios rated as May Be Appropriate facilitates the identification of areas where there may be gaps in evidence that would benefit from future research.

The American College of Cardiology (ACC) has a long history of developing documents (eg, expert consensus decision pathways, health policy statements, AUC documents) to provide members with guidance on both clinical and nonclinical topics relevant to cardiovascular care. In most circumstances, these documents have been created to complement clinical practice guidelines and to inform clinicians about areas where evidence is new and evolving or where sufficient data are more limited. Despite this, numerous gaps persist, highlighting the need for more streamlined and efficient processes to implement best practices in patient care.

Central to the ACC’s strategic plan is the generation of actionable knowledge —a concept that places emphasis on making clinical information easier to consume, share, integrate, and update. To this end, the ACC has shifted from developing isolated documents to creating integrated “solution sets.” These are groups of closely related activities, policy, mobile applications, decision-support tools, and other resources necessary to transform care and/or improve heart health. Solution sets address key questions facing care teams and attempt to provide practical guidance to be applied at the point of care. They use both established and emerging methods to disseminate information for cardiovascular conditions and their related management. The success of solution sets rests firmly on their ability to have a measurable impact on the delivery of care. Because solution sets reflect current evidence and ongoing gaps in care, the associated tools will be refined across time to match changing evidence and member needs.

AUC represent a key component of solution sets. They consist of common clinical scenarios associated with given disease states and ratings that define when it is reasonable to perform testing or provide therapies and, importantly, when it is not. AUC methodology relies on content development work groups, which create patient scenarios, and independent rating panels that employ a modified Delphi process to rate the relevant options for testing and intervention as Appropriate, May Be Appropriate, or Rarely Appropriate. AUC should not replace clinician judgment and practice experience but should function as tools to improve patient care and health outcomes in a cost-effective manner.

I extend sincere gratitude to the writing group for their invaluable contributions to the development of this document’s structure and clinical scenarios; to the rating panelists—a distinguished group of professionals with diverse expertise—for their thoughtful deliberation of the merits of device implantation across various clinical contexts; and to the reviewers for their thoughtful evaluation of the clinical scenarios and evidence mapping. Additionally, I am grateful to the members of the Solution Set Oversight Committee, which provided insight and guidance, and to ACC staff members María Velásquez and Lara Gold, for their support in bringing this document to fruition.

Low Risk of Inappropriate Shock Among Pediatric Patients With an Implantable Cardioverter Defibrillator: A Single Center Experience

Implantable cardioverter-defibrillators (ICD) are increasingly being used among the pediatric population for indications of both primary and secondary prevention. There is limited long-term data on the outcomes of pediatric patients following ICD implantation. The aim of this study was to investigate the characteristics of this population, burden of appropriate and inappropriate shock and complication rate in a large tertiary pediatric medical center. Included were children under the age of 18 years who underwent ICD implantation and had clinical follow up at our center. Data were retrospectively collected between study period 2005-2020. Primary outcome was the incidence of ICD shock appropriate and inappropriate. Secondary outcome was defining our patient population characteristics. Our cohort included 51 patients who underwent ICD implantation. Mean age at implantation was 10.9 ± 4.7 years and average follow-up time was 67 months. Diagnoses of implanted patients were: 28 (55%) patients with syndromes with risk for sudden death, cardiomyopathy in 14 patients (27%) and congenital heart disease (CHD) in 9 patients (18%). Forty-two (82%) patients had an ICD implanted for secondary prevention after experiencing a life-threatening arrhythmia and 9 (18%) for primary prevention. An endocardial system was implanted in 39 (76%) patients and an epicardial systems in 12 (24%) patients. A total of 20 (39%) patients received appropriate shocks for ventricular fibrillation(VF). 5 patients received inappropriate shocks, 4 due to sinus tachycardia and 1 due to rapidly conducted atrial fibrillation. Those who received an inappropriate shock had a significantly shorter ICD-programmed VF detection cycle length compared to those who did not receive an inappropriate shock (320 ms versus 270 ms, p = 0.062). This single center study demonstrates a high rate of appropriate ICD shocks (39%) and a low rate of inappropriate ICD shocks. Accurate programming of ICD devices in the pediatric population is paramount to avoid inappropriate ICD shocks.

Indications and management of implantable cardioverter-defibrillator therapy in childhood hypertrophic cardiomyopathy

Sudden cardiac death is the most common mode of death during childhood and adolescence in hypertrophic cardiomyopathy, and identifying those individuals at highest risk is a major aspect of clinical care. The mainstay of preventative therapy is the implantable cardioverter-defibrillator, which has been shown to be effective at terminating malignant ventricular arrhythmias in children with hypertrophic cardiomyopathy but can be associated with substantial morbidity. Accurate identification of those children at highest risk who would benefit most from implantable cardioverter-defibrillator implantation while minimising the risk of complications is, therefore, essential. This position statement, on behalf of the Association for European Paediatric and Congenital Cardiology (AEPC), reviews the currently available data on established and proposed risk factors for sudden cardiac death in childhood-onset hypertrophic cardiomyopathy and current approaches for risk stratification in this population. It also provides guidance on identification of individuals at risk of sudden cardiac death and optimal management of implantable cardioverter-defibrillators in children and adolescents with hypertrophic cardiomyopathy.

Etiology and device therapy in complete atrioventricular block in pediatric and young adult population: Contemporary review and new perspectives

Complete atrioventricular block (CAVB) is a total dissociation between the atrial and ventricular activity, in the absence of atrioventricular conduction. Several diseases may result in CAVB in the pediatric and young-adult population. Permanent right ventricular (RV) pacing is required in permanent CAVB, when the cause is neither transient nor reversible. Continuous RV apical pacing has been associated with unfavorable outcomes in several studies due to the associated ventricular dyssynchrony. This study aims to summarize the current literature regarding CAVB in the pediatric and young adult population and to explore future treatment perspectives.

Clinical Outcomes of Implantable Cardioverter-Defibrillator in Pediatric Patients - A Korean Multicenter Study

BACKGROUND

Implantable cardioverter-defibrillator (ICD) therapy is important for the prevention of sudden cardiac death, but data on clinical outcomes of ICD therapy in Asian pediatric patients are scarce. The aim of this Korean multicenter study was to evaluate the current state and elucidate the clinical outcomes of ICD therapy in children.

METHODS AND RESULTS

Data from 5 pediatric cardiology centers were retrospectively collected from 2007 to 2019. Altogether, 99 patients were enrolled (mean age 13.9±4.1 years). The most common underlying disease was a primary electrical disease (56%). An ICD was implanted for primary prevention in 19%. Appropriate shock occurred in 44% of patients at a median of 1.6 years after implantation. There was no significant difference in the appropriate shock rate between patients with primary and secondary prevention indications (32% vs. 48%, respectively). A total of 33 patients (33%) experienced inappropriate shock, which was associated with primary electrical disease and follow-up duration on multivariate analysis. 17% of patients had ICD-related complications.

CONCLUSIONS

The utilization rate of ICD for primary prevention was still low in the pediatric population in Korea, but there was a substantial rate of appropriate shock in these patients. Efforts to increase ICD usage to save the lives of high-risk patients and reduce the incidence of inappropriate shock are required.

Updated Approaches to Cardiac Electrical Stimulation and Pacing in Pediatrics

Cardiac electrical stimulation is a rarely used but required skill for pediatric emergency physicians. Children who are in cardiac arrest or who demonstrate evidence of hypoperfusion because of cardiac reasons require rapid diagnosis and intervention to minimize patient morbidity and mortality. Both hospital- and community-based personnel must have sufficient access to, and knowledge of, appropriate equipment to provide potentially lifesaving defibrillation, cardioversion, or cardiac pacing. In this review, we will discuss the primary clinical indications for cardioelectrical stimulation in pediatric patients, including the use of automated external defibrillators, internal defibrillators, and pacemakers. We discuss the types of devices that are currently available, emergency management of internal defibrillation and pacemaker devices, and the role of advocacy in improving delivery of emergency cardiovascular care of pediatric patients in the community.

Implantable cardiac electronic device therapy for patients with a systemic right ventricle

The systemic right ventricle (SRV), defined as the morphological right ventricle supporting the systemic circulation, is relatively common in congenital heart disease (CHD). Our review aimed at examining the current evidence, knowledge gaps and technical considerations regarding implantable cardiac electronic device therapy in patients with SRV. The risk of sinus node dysfunction (SND) after atrial switch repair and/or complete heart block in congenitally corrected transposition of great arteries requiring permanent pacing increases with age. Similar to acquired heart disease, indication for pacing includes symptomatic bradycardia, SND and high degree atrioventricular nodal block. Right ventricular dysfunction and heart failure also represent important complications in SRV patients. Cardiac resynchronisation therapy (CRT) has been proposed to improve systolic function in SRV patients, although indications for CRT are not well defined and its potential benefit remains uncertain. Amongst adult CHD, patients with SRV are at the highest risk for sudden cardiac death (SCD). Nevertheless, risk stratification for SCD is scarce in this cohort and implantable cardioverter-defibrillator indication is currently limited to secondary prevention. Vascular access and the incidence of device-related complications, such as infections, inappropriate shocks and device system failure, represent additional challenges to implantable cardiac electronic device therapy in patients with SRV. A multidisciplinary approach with tertiary expertise and future collaborative research are all paramount to further the care for this challenging nonetheless ever increasing cohort of patients.

Cardiac resynchronization and implantable defibrillators in adults with congenital heart disease

Cardiac resynchronization therapy (CRT) and implantable cardioverter defibrillators (ICDs) are well-established therapies for adult patients with heart failure that have been shown to improve morbidity and mortality. However, the benefits and indications for use in adults with congenital heart disease (ACHD) are less defined with no significant large prospective studies in this population. There are, however, multiple retrospective studies that demonstrate the efficacy of these devices in the ACHD population. These indicate a role for both CRT and ICDs in select patients with ACHD. The clinician and patient must balance the risks and benefits, summarized in complex evidence that reflects the heterogeneity of the ACHD patient group, and apply them in a patient-specific manner to optimize the utility of CRT and ICDs.

Allowing Adolescents to Weigh Benefits and Burdens of High-stakes Therapies

We present the case of a girl aged 17 years and 10 months who has a strong family history of long QT syndrome and genetic testing confirming the diagnosis of long QT syndrome in the patient also. She was initially medically treated with β-blocker therapy; however, after suffering 1 episode of syncope during exertion, she underwent placement of an implantable cardioverter defibrillator. Since then, she has never had syncope. However, during the few months before this presentation, she experienced shocks on multiple occasions without any underlying arrhythmias. These shocks are disconcerting for her, and she is having significant anxiety about them. She requests the defibrillator to be inactivated. However, her mother, who also shares the diagnosis of long QT syndrome, disagrees and wants the defibrillator to remain active. The ethics team is consulted in this setting of disagreement between an adolescent, who is 2 months shy of the age of maturity and medical decision-making, and her mother, who is currently responsible for her medical decisions. The question for the consultation is whether it would be ethically permissible for the doctors to comply with the patient's request to turn off the defibrillator or whether the doctors should follow the mother's wishes until the patient is 18 years of age.

Modern Technology for Prevention of Sudden Cardiac Death – a Clinical Update on Device Therapy in Children with Congenital Heart Diseases

Sudden cardiac death in children is one of the most devastating conditions that can be encountered in acute cardiac care. Intracardiac device therapy, providing prompt and effective treatment in malignant ventricular arrhythmia or in severe conduction abnormalities, is a promising tool to reduce the incidence of this fatal condition. However, the implementation of device-based therapy in the pediatric population is currently limited by the lack of clinical studies on large number of subjects. As a result, indications for device therapy in pediatric patients are still unclear in many circumstances. There are also several particularities related to device implantation in pediatric age, such as the somatic growth leading to a mismatch between chamber size and lead length, or the difficulties of implantation technique in children with small body weight. This study aims to present an update on the current advantages and limitations of device-based therapy for treating severe malignant arrhythmia or conduction disorders in children at risk for sudden cardiac death.

Implantable cardioverter defibrillator therapy in grown-up patients with transposition of the great arteries-role of anti-tachycardia pacing

Background

Grown-up patients with surgically corrected dextro-transposition of the great arteries (dTGA) as well as patients with congenitally corrected transposition of the great arteries (ccTGA) carry a high risk of ventricular arrhythmias. Data regarding implantable cardioverter defibrillator (ICD) therapy and efficacy of anti-tachycardia pacing in these patients is limited.

Methods

Clinical data from a contemporary cohort of ICD carriers with atrial switch-corrected dTGA and burdened right ventricle or with ccTGA were obtained retrospectively from hospital records and patients were followed for additional 25 months prospectively. Clinical characteristics and ICD episode data were analyzed.

Results

Fourteen ICD carriers (8 male) with dTGA or ccTGA were included in the analysis. Four patients received the ICD for primary prevention based on severely reduced systemic ventricular function. The remaining patients had an ICD indication for secondary prevention. Cumulative follow-up added up to 113.5 patient-years. One patient died suddenly due to massive pulmonary embolism. One patient received a ventricular assist device. There were no arrhythmic deaths during the prospective follow-up period. Nine patients (64%) experienced a total of 177 ventricular tachyarrhythmias. Anti-tachycardia pacing was highly effective with 80% success rate in termination of arrhythmias. Five patients (36%) suffered from a total of 28 inappropriate ICD shocks for supraventricular tachycardia.

Conclusions

In a contemporary cohort of ICD carriers with dTGA and ccTGA we observed a high proportion of appropriate ICD therapies for ventricular tachyarrhythmias. Over a period of up to 15 years almost two thirds of the patients received appropriate therapies. ATP was highly effective in our cohort and should therefore be programmed whenever possible.

Implantable Cardioverter-defibrillators in Adult Congenital Heart Disease

With improved surgical techniques and medical therapies, many patients who are born with complex congenital heart defects are now living well into adulthood. As these patients age, an increasingly common cause of mortality is sudden cardiac death (SCD) from ventricular tachyarrhythmias. The implantable cardioverter-defibrillator (ICD) is a therapy with the ability to prevent some of these deaths; however, there are many diagnostic and technical challenges that remain in the congenital heart disease (CHD) population. We performed a literature review, searching PubMed for articles that examined the role of ICDs in CHD. We herein present the evidence for when to place an ICD in CHD patients, stratified by subtype as relevant. Then, we discuss the technical challenges and complications that are unique to this patient population. We conclude that, despite active work in the area, more research is needed given the small event rates and clinical variability within CHD populations.

Decreased inappropriate shocks with new generation ICDs in children and patients with congenital heart disease

OBJECTIVE

Inappropriate implantable cardioverter defibrillator (ICD) shocks in children and patients with congenital heart disease (CHD) remain a major complication of device therapy, occurring in as many as 50% of children with ICDs. New generation devices include algorithms designed to minimize inappropriate shocks. This study aimed to evaluate the effect of new generation ICDs on the incidence of inappropriate shocks in the pediatric and CHD population.

DESIGN

Retrospective study of patients with CHD or under age 25 receiving ICDs between 2000 and 2015. New generation ICDs were defined as those with Medtronic "SmartShock" algorithms.

RESULTS

Two hundred eight devices were implanted in 146 patients. Rates of inappropriate shocks were similar between diagnoses (P = .71). The rate of inappropriate shock was 15% over median 5.8 years follow-up. In the 36 patients (25%) with new generation ICDs, the rate of inappropriate shock was 6.3% over 4 years. Comparing old to new generation ICDs, freedom from first inappropriate shock was 90.6% versus 97.1% at 1 year and 80.4% versus 97.1% at 3 years (P = .01). Lead fracture was associated with having inappropriate shock (hazard ratio 8.5, P < .0001), and there was no significant difference between the device groups when lead fractures were excluded. Clinical actions were taken in 69% of patients after initial inappropriate shock (such as medication or program change, system revision, or explant). When an action was taken, subsequent inappropriate shock was reduced (5.3% vs 49.2% at 1 year; P = .002).

CONCLUSIONS

Pediatric and CHD patients are experiencing reduced inappropriate shocks with new generation ICD systems, though reduced lead fracture may account for this improvement. Clinical interventions after inappropriate shock favorably impact the subsequent rate of shocks once an inappropriate shock occurs.

Inappropriate ICD Shocks in Pediatric and Congenital Heart Disease Patients

Although implantable cardioverter-defibrillators (ICDs) have proven to be life-saving devices, there are frequent complications associated with their use, especially in the pediatric and congenital heart disease populations. Inappropriate shocks are a particularly frequent complication in these groups. This review discusses the causes and implications of inappropriate ICD shocks, and presents potential interventions that may assist in safely reducing the rates of inappropriate shocks in pediatric and congenital heart disease patients with ICDs.

Implantable cardioverter-defibrillators in congenital heart disease

Implantable cardioverter-defibrillators (ICD) have an important role in reducing sudden cardiac death in patients with congenital heart disease (CHD); however, the benefit of ICDs needs to be weighed up against both short-term and long-term adverse effects, which are difficult to evaluate in the heterogeneous CHD population. A tailored approach, taking into account risk stratification and patient-specific factors, is needed to select the most appropriate strategy. This review discusses primary and secondary ICD indications, implantation approaches and long-term follow-up. Recent publications have shed light on the concerns of system longevity, lead extractions, inappropriate shocks and impact on the quality of life. All of these factors require consideration prior to commitment to this long-term treatment strategy.

Implantable Cardioverter Defibrillator Outcomes in Pediatric and Congenital Heart Disease: Time to System Revision

BACKGROUND

Implantable cardioverter defibrillators (ICDs) are intended to prevent sudden cardiac death yet also impose a risk of morbidity. This study describes the outcomes of ICDs in a pediatric and congenital heart disease (CHD) population from a single center.

METHODS

Retrospective cohort study of all patients with an ICD followed at the University of Michigan Congenital Heart Center from 2005-2013. The primary outcome was ICD system revision for any reason excluding routine generator change for battery depletion.

RESULTS

There were 191 ICD systems in 131 patients, including 57 with CHD, 24 with hypertrophic cardiomyopathy, and 45 with structurally normal hearts. Median age was 16 years at initial implant. Total follow-up was 850 patient-years; median 4.9 years/patient. There were 43 (33%) patients who required 60 ICD revisions; 70 revisions/1,000 patient-years of follow-up. Revisions included 25 lead extractions with replacement, 21 lead additions, five lead repositions, and four full system revisions. Kaplan-Meier (K-M) median time to appropriate shock was similar to the median time to system revision. K-M time to system revision was significantly affected by recalled lead performance.

CONCLUSIONS

The need for ICD system revision is high in this pediatric and CHD population and occurs at a rate similar to the rate of receiving appropriate therapy. These results highlight the need for judicious implant criteria and improved device longevity.

Implanted defibrillators in young hypertrophic cardiomyopathy patients: a multicenter study

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease, with an annual risk of sudden cardiac death (SCD) estimated at 1 %. Limited data are available regarding both the risk of SCD in the young HCM population and the use of implantable cardioverter-defibrillators (ICDs). This retrospective study included all patients with HCM who underwent ICD implantation for primary or secondary prevention of SCD before the age of 30 years at five institutions between 1995 and 2009. There were 99 devices implanted in 73 patients. Appropriate shocks occurred for 11 % of all the patients. None of the previously identified conventional risk factors for SCD in HCM patients were associated with increased risk of appropriate shocks in the young study cohort. During a median follow-up period of 2.4 years, inappropriate shocks occurred for 22 % of the patients. Older age at implant was associated with a decreased risk of inappropriate shock. Those who underwent implantation in the earlier decade had a higher incidence of inappropriate shocks. Late complications including lead fracture or dislodgement, generator malfunction, and infection occurred for 32 % of the patients. Three patients died (4 %), one of whom had an arrhythmic sudden death. A greater proportion of primary prevention implantations was performed for patients from the latter decade. Over time, ICD use in young HCM patients has become increasingly primary prevention oriented. Shock rates mirror those reported in adult series, and there is a substantial incidence of device complications.

Pediatric cardiovascular safety: challenges in drug and device development and clinical application

Development of pediatric medications and devices is complicated by differences in pediatric physiology and pathophysiology (both compared with adults and within the pediatric age range), small patient populations, and practical and ethical challenges to designing clinical trials. This article summarizes the discussions that occurred at a Cardiac Safety Research Consortium-sponsored Think Tank convened on December 10, 2010, where members from academia, industry, and regulatory agencies discussed important issues regarding pediatric cardiovascular safety of medications and cardiovascular devices. Pediatric drug and device development may use adult data but often requires additional preclinical and clinical testing to characterize effects on cardiac function and development. Challenges in preclinical trials include identifying appropriate animal models, clinically relevant efficacy end points, and methods to monitor cardiovascular safety. Pediatric clinical trials have different ethical concerns from adult trials, including consideration of the subjects' families. Clinical trial design in pediatrics should assess risks and benefits as well as incorporate input from families. Postmarketing surveillance, mandated by federal law, plays an important role in both drug and device safety assessment and becomes crucial in the pediatric population because of the limitations of premarketing pediatric studies. Solutions for this wide array of issues will require collaboration between academia, industry, and government as well as creativity in pediatric study design. Formation of various epidemiologic tools including registries to describe outcomes of pediatric cardiac disease and its treatment as well as cardiac effects of noncardiovascular medications, should inform preclinical and clinical development and improve benefit-risk assessments for the patients. The discussions in this article summarize areas of emerging consensus and other areas in which consensus remains elusive and provide suggestions for additional research to further our knowledge and understanding of this topic.