Cardiac resynchronisation therapy in paediatric and congenital heart disease: differential effects in various anatomical and functional substrates

Updates in Arrhythmia Management in Adult Congenital Heart Disease

Arrhythmias are highly prevalent in adults with congenital heart disease. For the clinician caring for this population, an understanding of pathophysiology, diagnosis, and management of arrhythmia is essential. Herein we review the latest updates in diagnostics and treatment of tachyarrhythmias and bradyarrhythmias, all in the context of congenital anatomy, hemodynamics, and standard invasive palliations for congenital heart disease.

Assessing Non-invasive Studies to Evaluate Resynchronization Pacing Effectiveness in the Young

Appropriate non-invasive assessments (ECHO/ECG) of cardiac resynchronization pacing therapy (CRT) among younger patients (pts) with/without (w/wo) congenital heart disease (CHD) are not established. Ejection fraction (EF) and QRS can be unreliable due to anatomy, surgical repairs, and pre-existing pacemakers (PM). This study correlates updated non-invasive studies, including newer strain values, with clinical and invasive hemodynamic assessments of CRT response in the young. Sixteen pts (mean age 18.5 ± 6 years, 10/16 with pre-existing pacemakers) underwent CRT for heart failure (NYHA II-III). CHD included septal defects and Tetralogy of Fallot. Assessment of CRT efficacy was based on clinical findings, direct catheterization studies [pressures, contractility indices (dP/dt-max)], ECG changes, and ECHO studies [including updated global (GLS), left atrial strain (LAS), and sphericity indices] pre- and at 1-month and 1-year post-CRT. After 1 year following CRT, all pts improved (II-III to I-II) in clinical NYHA status. Contractility (dP/dt) increased (932 ± 351 vs 561 ± 178.7 mmHg-sec [p = 0.001]). QRS duration shortened only among pts with pre-existing PM (160 ± 25 vs 134 ± 25 ms [p = 0.02]). Standard ECHO parameters, including chamber dimensions and EF, showed no appreciable changes from pre-CRT values. However, endocardial GLS [(- 6.4 vs. - 9.6%) p = 0.0003] and LAS [(- 5.8 vs - 9.3%) p = 0.02] values significantly improved. Although CRT is applicable to younger pts, accurate non-invasive evaluations of response are lacking. This study establishes that newer strain values better correlate with clinical and hemodynamic changes over other parameters and offer more appropriate assessments of CRT response.

Trends in cardiac implantable electronic device utilization in adults with congenital heart disease: a US nationwide analysis

BACKGROUND

Adults with congenital heart disease (ACHD) have increased risk of arrhythmias warranting implantation of cardiac implantable electronic devices (CIEDs), which may parallel the observed increase in survival of ACHD patients over the past few decades. We sought to characterize the trends and outcomes of CIED implantation in the inpatient ACHD population across US from 2005 to 2019.

METHODS

A retrospective analysis of the Nationwide Inpatient Sample (NIS) identified 1,599,519 unique inpatient ACHD admissions (stratified as simple (85.1%), moderate (11.5%), and complex (3.4%)) using the International Classification of Diseases 9/10-CM codes. Hospitalizations for CIED implantation (pacemaker, ICD, CRT-p/CRT-d) were identified and the trends analyzed using regression analysis (2-tailed p < 0.05 was considered significant).

RESULTS

A significant decrease in the hospitalizations for CIED implantation across the study period [3.3 (2.9-3.8)% in 2005 vs 2.4 (2.1-2.6)% in 2019, p < 0.001] was observed across all types of devices and CHD severities. Pacemaker implantation increased with each age decade, whereas ICD implantation rates decreased over 70 years of age. Complex ACHD patients receiving CIED were younger with a lower prevalence of age-related comorbidities, however, had a greater prevalence of atrial/ventricular tachyarrhythmias and complete heart block. The observed inpatient mortality rate was 1.2%.

CONCLUSIONS

In a nationwide analysis, we report a significant decline in CIED implantation between 2005 and 2019 in ACHD patients. This may either be due to a greater proportion of hospitalizations resulting from other complications of ACHD or reflect a declining need for CIED due to advances in medical/surgical therapies. Future prospective studies are needed to elucidate this trend further.

Outcomes of cardiac resynchronization therapy in congenital heart disease: A meta-analysis and systematic review

INTRODUCTION

Cardiac resynchronization therapy (CRT) is a standard treatment for patients with heart failure with reduced ejection fraction. However, there is still a gap of evidence in congenital heart disease (CHD) patients regarding resynchronization therapy.

METHODS

We performed a meta-analysis and systematic review of CHD patients who received CRT implantation. We comprehensively searched the databases of MEDLINE, EMBASE, and Cochrane database from inception to June 2023. Studies that reported response rate to CRT, total mortality rate, change in QRS duration, change in left ventricular ejection fraction, and change in New York Heart Association functional class were included.

RESULTS

A total of 14 studies were included in the study. There were 10 studies that reported response rates after implantation. The overall response rate to CRT in CHD patients was 68% (95% confidence interval [CI] 61%-75%, I2 32%). The response rates in patients with systemic right ventricle (RV), systemic left ventricle (LV), and single ventricle were 58% (95% CI 46%-70%, I2 0%), 80% (95% CI 74%-86% I2 14%), and 67% (95% CI 49%-80% I2 0%). Response to CRT in systemic RV was inferior to systemic LV with an odds ratio of 0.38 (95% CI 0.15-0.95, I2 38%). The total mortality rate from seven studies was 12% (95% CI 8%-18%, I2 55%). The parameters which represented ventricular dyssynchrony improved after CRT implantation.

CONCLUSION

The overall response rate to CRT in CHD was 68%. Patients with systemic RV had a lower response rate to CRT when compared to patients with systemic LV. The total mortality rate after CRT implantation was 12%.

Multicenter Study of Survival Benefit of Cardiac Resynchronization Therapy in Pediatric and Congenital Heart Disease

BACKGROUND

Evidence for the efficacy of cardiac resynchronization therapy (CRT) in pediatric and congenital heart disease (CHD) has been limited to surrogate outcomes.

OBJECTIVES

This study aimed to assess the impact of CRT upon the risk of transplantation or death in a retrospective, high-risk, controlled cohort at 5 quaternary referral centers.

METHODS

Both CRT patients and control patients were <21 years of age or had CHD; had systemic ventricular ejection fraction <45%; symptomatic heart failure; and significant electrical dyssynchrony (QRS duration z score >3 or single-site ventricular pacing >40%) at enrollment. Patients with CRT were matched with control patients via 1:1 propensity score matching. CRT patients were enrolled at CRT implantation; control patients were enrolled at the outpatient clinical encounter where inclusion criteria were first met. The primary endpoint was transplantation or death.

RESULTS

In total, 324 control patients and 167 CRT recipients were identified. Mean follow-up was 4.2 ± 3.7 years. Upon propensity score matching, 139 closely matched pairs were identified (20 baseline indices). Of the 139 matched pairs, 52 (37.0%) control patients and 31 (22.0%) CRT recipients reached the primary endpoint. On both unadjusted and multivariable Cox regression analysis, the risk reduction associated with CRT for the primary endpoint was significant (HR: 0.40; 95% CI: 0.25-0.64; P < 0.001; and HR: 0.44; 95% CI: 0.28-0.71; P = 0.001, respectively). On longitudinal assessment, the CRT group had significantly improved systemic ventricular ejection fraction (P < 0.001) and shorter QRS duration (P = 0.015), sustained to 5 years.

CONCLUSIONS

In pediatric and CHD patients with symptomatic systolic heart failure and electrical dyssynchrony, CRT was associated with improved heart transplantation-free survival.

Indications for Cardiac Resynchronization Therapy in Patients with Congenital Heart Disease

Heart failure in patients with congenital heart disease (CHD) stems from unique causes compared with the elderly. Patients with CHD face structural abnormalities and malformations present from birth, leading to altered cardiac function and potential complications. In contrast, elderly individuals primarily experience heart failure due to age-related changes and underlying cardiovascular conditions. Cardiac resynchronization therapy (CRT) can benefit patients with CHD, although it presents numerous challenges. The complexities of CHD anatomy and limited access to appropriate venous sites for lead placement make CRT implantation demanding.

Techniques for Cardiac Resynchronization Therapy in Patients with Congenital Heart Disease

Cardiac resynchronization therapy (CRT) for congenital heart disease has shown promising suucess as an adjunct to medical therapy for heart failure. While cardiac conduction defects and need for ventricular pacing are common in congential heart disease, CRT indications, techniques and long term outcomes have not been well establaished. This is a review of the techniques nad short term outcomes of CRT for the following complex congenital heart disease conditions: single ventricle physiology, systemic right ventricle, and the subpulmonic right ventricle.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

Advancing the science of management of arrhythmic disease in children and adult congenital heart disease patients within the last 25 years

This review article reflects how publications in EP Europace have contributed to advancing the science of management of arrhythmic disease in children and adult patients with congenital heart disease within the last 25 years. A special focus is directed to congenital atrioventricular (AV) block, the use of pacemakers, cardiac resynchronization therapy devices, and implantable cardioverter defibrillators in the young with and without congenital heart disease, Wolff-Parkinson-White syndrome, mapping and ablation technology, and understanding of cardiac genomics to untangle arrhythmic sudden death in the young.

Pediatric Epicardial Devices: Early and Midterm Outcomes

BACKGROUND

Lead performance is suboptimal in young patients and a main cause of device system failure. Our objective was to assess early and midterm outcomes after epicardial device implantation in a contemporary pediatric cohort.

METHODS

A total of 116 consecutive pediatric patients underwent 137 epicardial device implantations from 2010 to 2019. Forty pacemakers and 97 implantable cardioverter defibrillators (ICDs) were implanted. Lead failure was defined as leads repaired, replaced, or abandoned due to fracture, dislodgement, or dysfunction. Freedom from device system failure was determined using Kaplan-Meier analysis.

RESULTS

Mean age at implantation was 10 ± 5 years, 46 (34%) were younger than 8 years old, 41 (30%) had prior cardiac surgery, and 38 (28%) had prior devices. Main indications were acquired heart block (17/40 [43%]), sinus node dysfunction (14/40 [35%]), and congenital heart block (7/40 [18%]) for pacemakers, and hypertrophic cardiomyopathy (46/97 [47%]), long QT syndrome (31/97 [32%]), and ventricular arrhythmia (17/97 [18%]) for ICDs. There were no early deaths. Three-year freedom from device system failure was 80% (95% CI 73%, 88%) for all patients and 88% (95% CI 79%, 99%) for patients <8 years old. Device system failure causes included lead fracture (20/34 [59%]), lead dysfunction (5/34 [15%]), lead dislodgement (5/34 [15%]), infection (3/34 [9%]), and pericarditis (1/34 [3%]). Reintervention was required in 26/34 (76%) device system failures.

CONCLUSIONS

Epicardial device implantation is safe, shows acceptable midterm outcomes in children, and is an effective option in patients younger than 8 years old. Close device surveillance continues to be essential to detect lead failure early and ensure timely reintervention.

Congenitally corrected transposition: not correct at all

PURPOSE OF REVIEW

Congenitally corrected transposition of the great arteries is a rare congenital defect with several management options. Disagreement continues on strategies, such as anatomic repair, physiologic repair or observation-only. This review discusses recent data that provide further guidance for clinical decision-making.

RECENT FINDINGS

New data provide greater insights into practice patterns and outcomes. Recent data from high-volume centers show progressively high rates of systemic right ventricle dysfunction over time with lower rates of systemic left ventricle dysfunction following anatomic repair; there is a statistical trend towards better survival of anatomic repair patients. Data comparing anatomic repair to observation showed that anatomic repair patients had a lower hazard of reaching a composite adverse outcome. These complex operations are predominantly performed at a small subset of congenital heart surgery centers.

SUMMARY

Anatomic repair compared with physiologic repair may have better outcomes, although there are relatively high rates of morbidity for both approaches. In the patient without associated lesions, nonsurgical management can have excellent outcomes but is complicated by right ventricular failure over time. Multicenter research will help determine risk factors for bad outcomes; management at high volume, experienced centers will probably be beneficial for this complex patient population.

Percutaneous epicardial pacing in infants using direct visualization: A feasibility animal study

BACKGROUND

Pacemaker implantation in infants and small children is limited to epicardial lead placement via open chest surgery. We propose a minimally invasive solution using a novel percutaneous access kit.

OBJECTIVE

To evaluate the acute safety and feasibility of a novel percutaneous pericardial access tool kit to implant pacemaker leads on the epicardium under direct visualization.

METHODS

A custom sheath with optical fiber lining the inside wall was built to provide intrathoracic illumination. A Veress needle inside the illumination sheath was inserted through a skin nick just to the left of the xiphoid process and angled toward the thorax. A needle containing a fiberscope within the lumen was inserted through the sheath and used to access the pericardium under direct visualization. A custom dilator and peel-away sheath with pre-tunneled fiberscope was passed over a guidewire into the pericardial space via modified Seldinger technique. A side-biting multipolar pacemaker lead was inserted through the sheath and affixed against the epicardium.

RESULTS

Six piglets (weight 3.7-4.0 kg) had successful lead implantation. The pericardial space could be visualized and entered in all animals. Median time from skin nick to sheath access of the pericardium was 9.5 (interquartile range [IQR] 8-11) min. Median total procedure time was 16 (IQR 14-19) min. Median R wave sensing was 5.4 (IQR 4.0-7.3) mV. Median capture threshold was 2.1 (IQR 1.7-2.4) V at 0.4 ms and 1.3 (IQR 1.2-2.0) V at 1.0 ms. There were no complications.

CONCLUSION

Percutaneous epicardial lead implantation under direct visualization was successful in six piglets of neonatal size and weight with clinically acceptable acute pacing parameters.

Heart failure in systemic right ventricle: Mechanisms and therapeutic options

d-loop transposition of the great arteries (d-TGA) and congenitally corrected transposition of the great arteries (cc-TGA) feature a right ventricle attempting to sustain the systemic circulation. A systemic right ventricle (sRV) cannot support cardiac output in the long run, eventually decompensating and causing heart failure. The burden of d-TGA patients with previous atrial switch repair and cc-TGA patients with heart failure will only increase in the coming years due to the aging adult congenital heart disease population and improvements in the management of advanced heart failure. Clinical data still lags behind in developing evidence-based guidelines for risk stratification and management of sRV patients, and clinical trials for heart failure in these patients are underrepresented. Recent studies have provided foundational data for the commencement of robust clinical trials in d-TGA and cc-TGA patients. Further insights into the multifactorial nature of sRV failure can only be provided by the results of such studies. This review discusses the mechanisms of heart failure in sRV patients with biventricular circulation and how these mediators may be targeted clinically to alleviate sRV failure.

Interamerican Society of Cardiology (CIFACAH - ELECTROSIAC)/Latin American Heart Rhythm Society (LAHRS): multidisciplinary review on the appropriate use of cardiac resynchronization therapy in heart failure

Epidemiological studies suggest that approximately half of the patients with heart failure (HF) have reduced ejection fraction, while the other half have normal ejection fraction (EF). Currently, international guidelines consider QRS duration greater than 130 ms, in the presence of ventricular dysfunction (EF < 35%), as a criterion for selecting patients for cardiac resynchronization therapy (CRT). CRT helps restore intraventricular and auriculoventricular synchrony, improving left ventricular (LV) performance, reducing functional mitral regurgitation, and inducing reverse LV remodeling. This is evidenced by increased LV filling time and left ventricular ejection fraction, decreased LV end-diastolic and end-systolic volumes, mitral regurgitation, and septal dyskinesia. Because the mechanisms of dyssynchrony may be heterogeneous, no single measure may accurately predict response to CRT. Finally, CRT has been progressively shown to be safe and feasible, improves functional status and quality of life, reversely remodels the LV, decreases the number of hospitalizations, total mortality in patients with refractory HF, LV dysfunction, and intraventricular conduction disorders; is a pacemaker-based therapy for HF and thanks to current technology, safe remote monitoring of almost all types of cardiac devices is possible and provides useful alerts in clinical practice.

Late Outcomes of Pediatric and Congenital Heart Disease Patients Following Cardiac Resynchronization Therapy

BACKGROUND AND OBJECTIVES

Cardiac resynchronization therapy (CRT) is an effective treatment for heart failure. However, in pediatric and congenital heart disease (CHD) patients, current adult indications cannot be directly applied because of heterogeneity in anatomy and diagnosis. Therefore, CRT responses and clinical outcomes in these patients were investigated to derive possible candidates for CRT.

METHODS

This study retrospectively analyzed 16 pediatric and CHD patients who underwent CRT implantation at a single center in early (0.7±0.2 year) and late (4.7±0.3 years) follow-up period after CRT.

RESULTS

The median age at CRT implantation was 2.5 (0.3-37.2) years, and median follow-up duration was 6.3 (0.1-13.6) years. Thirteen had non-transvenous CRT. Two had congenital complete atrioventricular (AV) block with previous right ventricular pacing, 5 had dilated cardiomyopathy (DCM) with left bundle branch block, and 9 had CHD. The mean ejection fraction of the systemic ventricle increased from 28.1±10.0% to 44.3±21.0% (p=0.003) in early and 51.8±16.3% (p=0.012) in late outcome. The mean functional class improved from 3.1±0.9 to 1.8±1.1 after CRT (p=0.003). Twelve patients (75%) showed improvement in ventricular function or functional class after CRT. Proportion of responders differed between patients without CHD (2/2 patients with complete AV block and 5/5 with DCM, 100%) and those with CHD (5/9, 56%), although statistical significance was not reached (p=0.088).

CONCLUSIONS

CRT improved ventricular function and functional status according to the underlying condition in pediatric and CHD patients. However, further large and longer-term studies are needed to establish the guideline for the patient selection of CRT in these patients.

Cardiac Resynchronization Therapy for Adult Patients With a Failing Systemic Right Ventricle: A Multicenter Study

Background

The objective of this international multicenter study was to investigate both early and late outcomes of cardiac resynchronization therapy (CRT) in patients with a systemic right ventricle (SRV) and to identify predictors for congestive heart failure readmissions and mortality.

Methods and Results

This retrospective international multicenter study included 13 centers. The study population comprised 80 adult patients with SRV (48.9% women) with a mean age of 45±14 (range, 18–77) years at initiation of CRT. Median follow‐up time was 4.1 (25th–75th percentile, 1.3–8.3) years. Underlying congenital heart disease consisted of congenitally corrected transposition of the great arteries and dextro‐transposition of the great arteries in 63 (78.8%) and 17 (21.3%) patients, respectively. CRT resulted in significant improvement in functional class (before CRT: III, 25th–75th percentile, II–III; after CRT: II, 25th–75th percentile, II–III; P =0.005) and QRS duration (before CRT: 176±27; after CRT: 150±24 milliseconds; P =0.003) in patients with pre‐CRT ventricular pacing who underwent an upgrade to a CRT device (n=49). These improvements persisted during long‐term follow‐up with a marginal but significant increase in SRV function (before CRT; 30%, 25th–75th percentile, 25–35; after CRT: 31%, 25th–75th percentile, 21–38; P =0.049). In contrast, no beneficial change in the above‐mentioned variables was observed in patients who underwent de novo CRT (n=31). A quarter of all patients were readmitted for heart failure during follow‐up, and mortality at latest follow‐up was 21.3%.

Conclusions

This international experience with CRT in patients with an SRV demonstrated that CRT in selected patients with SRV dysfunction and pacing‐induced dyssynchrony yielded consistent improvement in QRS duration and New York Heart Association functional status, with a marginal increase in SRV function.

Conduction System Pacing Versus Conventional Cardiac Resynchronization Therapy in Congenital Heart Disease

BACKGROUND

Dyssynchrony-associated left ventricular systolic dysfunction is a major contributor to heart failure in congenital heart disease (CHD). Although conventional cardiac resynchronization therapy (CRT) has shown benefit, the comparative efficacy of cardiac conduction system pacing (CSP) is unknown.

OBJECTIVES

To compare the clinical outcomes of CSP vs conventional CRT in CHD with biventricular, systemic left ventricular anatomy.

METHODS

Retrospective CSP data from 7 centers were compared with propensity score-matched conventional CRT control subjects. Outcomes were lead performance, change in left ventricular ejection fraction (LVEF), and QRS duration at 12 months.

RESULTS

A total of 65 CSP cases were identified (mean age 37 ± 21 years, 46% men). The most common CHDs were tetralogy of Fallot (n = 12 [19%]) and ventricular septal defect (n = 12 [19%]). CSP was achieved after a mean of 2.5 ± 1.6 attempts per procedure (38 patients with left bundle branch pacing, 17 with HBP, 10 with left ventricular septal myocardial). Left bundle branch area pacing [LBBAP] vs HBP was associated with a smaller increase in pacing threshold (Δ pacing threshold 0.2 V vs 0.8 V; P = 0.05) and similar sensing parameters at follow-up. For 25 CSP cases and control subjects with baseline left ventricular systolic dysfunction, improvement in LVEF was non-inferior (Δ LVEF 9.0% vs 6.0%; P = 0.3; 95% confidence limits: -2.9% to 10.0%) and narrowing of QRS duration was more pronounced for CSP (Δ QRS duration 35 ms vs 14 ms; P = 0.04). Complications were similar (3 [12%] CSP, 4 [16%] conventional CRT; P = 1.00).

CONCLUSIONS

CSP can be reliably achieved in biventricular, systemic left ventricular CHD patients with similar improvement in LVEF and greater QRS narrowing for CSP vs conventional CRT at 1 year. Among CSP patients, pacing electrical parameters were superior for LBBAP vs HBP.

Treatment of advanced heart failure in adults with congenital heart disease: a narrative review and clinical cases

BACKGROUND AND OBJECTIVE

The number of adults with congenital heart disease (ACHD) is increasing worldwide. Almost all congenital cardiac lesions can be successfully treated due to the progress in neonatal surgery and pediatric cardiology with a high likelihood of surviving until adulthood. However, ACHD frequently develop sequelae related to the initial cardiac anomaly. Heart failure (HF) is one of the most common complications associated with a high morbidity and mortality.

METHODS

The authors did search the PubMed database regarding relevant content covering publications up to March 2022. Relevant manuscripts were classified according to the impact factor of the journal, being a guideline manuscript, a position paper by a society or a comprehensive review of the current literature.

KEY CONTENT AND FINDINGS

Optimal HF treatment remains an unmet need in ACHD. In particular, advanced HF therapy with cardiac resynchronization therapy, ventricular assist devices or organ transplantation is still very different and more specific in ACHD compared to non-ACHD. This review aims to compile international views and evidence from the literatures on the treatment of advanced HF in ACHD. Current challenges, but also the success of different treatment strategies in ACHD are illustrated by clinical cases.

CONCLUSIONS

The main finding of the review is that data is still scarce regarding ACHD with advanced HF and international efforts to collect data regarding these patients needed to improve the current standard of care.

The history of cardiac pacing in the young and a look to the future

PURPOSE OF REVIEW

The purpose of this review is to explore the historical and serendipitous events that led to the creation of modern-day pacemakers. In addition, this review will explore how contemporary conduction site-specific pacing has overcome some of the deleterious effects from historical chronic right ventricular apical pacing.

RECENT FINDINGS

Recently, there have been tremendous advances in not just the lead design but the tools required to promote more physiologic pacing. Although cardiac resynchronization pacing has been around for nearly 2 decades, this review also introduces and discusses the early results of His-bundle pacing and left bundle branch pacing and some of the potential applicability of this technology for our children.

SUMMARY

Pacemakers have evolved significantly in the last 30 years through collaborative partnerships between physicians and engineers. The future of cardiac pacing is bright compared to the field of electrotherapy 50 years ago. Future iterations of pacemakers must consider unusual anatomy and growing children. Pediatric patients contribute to a small percentage of the overall device volume, but the majority of these patients will have a pacemaker for life. We need to be proactive and consider what are the best short and long-term solutions for this cohort.

Updates in the management of congenital heart disease in adult patients

INTRODUCTION

Adults with congenital heart disease represent a highly diverse, ever-growing population. Optimal approaches to management of problems such as arrhythmia, sudden cardiac death, heart failure, transplant, application of advanced therapies and unrepaired shunt lesions are incompletely established. Efforts to strengthen our understanding of these complex clinical challenges and inform evidence-based practices are ongoing.

AREAS COVERED

This narrative review summarizes evidence underpinning current approaches to congenital heart disease management while highlighting areas requiring further investigation. A search of literature published in 'Medline,' 'EMBASE,' and 'PubMed' using search terms 'congenital heart disease,' 'arrhythmia,' 'sudden cardiac death,' 'heart failure,' 'heart transplant,' 'advanced heart failure therapy,' 'ventricular assist device (VAD),' 'mechanical circulatory support (MSC),' 'intracardiac shunt' and combinations thereof was undertaken.

EXPERT OPINION

Application of novel technologies in the diagnosis and management of arrhythmia has and will continue to improve outcomes in this population. Sudden death remains a prevalent problem with many persistent unknowns. Heart failure is a leading cause of morbidity and mortality. Improved access to specialist care, advanced therapies and cardiac transplant is needed. The emerging field of cardio-obstetrics will continue to define state-of-the-art care for the reproductive health of women with heart disease.

Prevalence and Prognostic Implications of Left Ventricular Systolic Dysfunction in Adults With Congenital Heart Disease

BACKGROUND

Although the prevalence and prognostic implications of left ventricular systolic dysfunction (LVSD), and the effect of cardiac therapies on LVSD are well described in patients with acquired heart disease, such data are sparse in adults with congenital heart disease (CHD).

OBJECTIVES

The purpose of this study was to determine the prevalence, risk factors, and prognostic implications of LVSD, and the effect of cardiac therapies (guideline-directed medical therapy [GDMT] and cardiac resynchronization therapy [CRT]) on LVSD in adults with CHD.

METHODS

This was a retrospective study of adults with CHD with systemic LV (2003-2019). LVSD was defined as left ventricular ejection fraction (LVEF) <52%/<54% (men/women). Cardiovascular event was defined as heart failure hospitalization, heart transplant, and cardiovascular death.

RESULTS

Of 4,358 patients, 554 (12%) had LVSD, and the prevalence of LVSD was higher in right-sided lesions compared with left-sided lesions (15% vs 10%; P < 0.001). Cardiovascular events occurred in 312 (7%) patients. LVEF was independently associated with cardiovascular events (HR: 0.95; 95% CI: 0.93-0.97; P = 0.009). Of 544 patients with LVSD, 311 received GDMT and 48 patients received CRT. LVEF increased by 6% (95% CI: 2%-10%) and 11% (95% CI: 8%-14%), and N-terminal pro-hormone brain natriuretic peptide decreased by 151 pg/mL (95% CI: 62-289 pg/mL) and 201 pg/mL (95% CI: 119-321 pg/mL) in patients who received GDMT and CRT, respectively.

CONCLUSIONS

LVSD was present in 12% of adults with CHD, was more common in patients with right-sided lesions, and was associated with cardiovascular events. GDMT and CRT were associated with improvement in LVEF. These results provide a foundation for clinical trials to rigorously test the benefits of these therapies in CHD patients.

Cardiac resynchronization therapy in patients with congenital heart disease and systemic right ventricle

BACKGROUND

Although patients with systemic right ventricle (SRV) represent a significant proportion of patients with congenital heart disease (CHD) implanted with cardiac resynchronization therapy (CRT), there are limited and conflicting data in this specific patient group.

OBJECTIVE

We aimed to analyze outcomes of patients with SRV implanted with a CRT device.

METHODS

Data were analyzed from an observational, retrospective, multicenter cohort study including all patients with CHD implanted with a CRT device from 6 French centers from 2004 to 2020. Response to CRT was defined as an increase in systemic ventricular ejection fraction of ≥10% and/or an improvement in New York Heart Association functional class by at least 1 grade.

RESULTS

A total of 85 patients with CHD were enrolled (mean age 39.8 ± 20.0 years; 55 [64.7%] males; 25 defibrillators [29.4%]), including 31 patients with SRV (36.5%) (mean age 43.9 ± 19.8 years; 16 [51.6%] males). The mean change in QRS duration after implantation was similar as compared with patients with systemic left ventricle (-46 ± 26 ms vs -35 ± 32 ms; P = .16). During a mean follow-up of 5.1 ± 3.5 years, late complications included 2 lead dysfunctions (6.5%), 3 CRT-related infections (9.7%), and 1 inappropriate implantable cardioverter-defibrillator shock (3.2%). The proportion of CRT responders at 6, 12, and 24 months were 82.6%, 80.0%, and 77.8% in patients with SRV vs 66.7%, 64.3%, and 69.6% in patients with systemic left ventricle (P = NS).

CONCLUSION

In this multicenter cohort, one-third of patients with CHD implanted with a CRT device had SRV. CRT in patients with SRV was associated with a high rate of responders, comparable to that of patients with systemic left ventricle.

Cardiac resynchronisation therapy in a pace-dependent infant with tetralogy of Fallot

We present the case of a 5-month-old infant with tetralogy of Fallot and congenital atrio-ventricular block that developed severe left ventricular dysfunction during apical left ventricular pacing, in which cardiac resynchronisation therapy was used as an emergency procedure due to persistent low cardiac output syndrome.

Cardiac resynchronization therapy in paediatric patients with congenital heart disease: single centre with 10 years of experience

OBJECTIVES

In recent years, cardiac resynchronization therapy (CRT) has also started to be performed in the paediatric and CHD population. This study aimed to evaluate the efficacy of CRT in children with CHD.

PATIENTS AND METHODS

Patients with CHD who underwent CRT treatment in our paediatric cardiology clinic between January, 2010 and January, 2020 were included in the study. Demographic findings, 12-lead electrocardiograms, echocardiograms, clinical characteristics, management strategies, and outcomes were reviewed systematically.

RESULTS

The study population consisted of 18 CHD patients who had been treated with CRT for 10 years in our institution. The median age was 11 years (2.2-18 years) and the median weight was 39 kg (10-81 kg). Systemic ventricle was left ventricle in 13 patients, right ventricle in 4 patients, and 1 patient had single-ventricle physiology. CRT implantation indications were as follows: dysfunction after permanent pacemaker in 11 patients, dysfunction after left bundle branch block in 4 patients, and systemic ventricular dysfunction in 3 patients. CRT implantation techniques were epicardial (n = 13), hybrid (n = 4), and transvenous (n = 1) methods. QRS duration significantly decreased after CRT implantation (160 versus 124 m/second, p < 0.05). Median systemic ventricle ejection fraction (EF) significantly increased after the procedure (30 versus 50%, p < 0.05). Fourteen patients (78%) were responders, two patients (11%) were superresponders, and two patients (11%) were non-responders after the CRT treatment. One patient deceased during follow-up. Median follow-up duration was 40 months (6-117 months).

CONCLUSION

When electromechanical dyssynchrony occurs in paediatric cases with CHD and developing heart failure, patients should be evaluated in terms of CRT to improve ventricular function. Alternative CRT therapy will be beneficial in these cases that do not improve clinically despite optimal medical treatment.

Heart failure with reduced and preserved ejection fraction in adult congenital heart disease

Heart failure with reduced ejection fraction (HFrEF) is common in patients with adult congenital heart disease. Many of the most common congenital defects have a high prevalence of HFrEF, including left-sided obstructive lesions (aortic stenosis, coarctation of the aorta, Shone complex), tetralogy of Fallot, Ebstein anomaly, lesions in which there is a systemic right ventricle, and lesions palliated with a Fontan circulation. However, heart failure with preserved ejection fraction (HFpEF) is also prevalent in all these lesions. Comprehensive evaluation includes physical exam, biomarkers, echocardiography and advanced imaging, exercise stress testing, and, in some cases, invasive hemodynamics. Guideline-directed medical therapy for HFrEF can be applied to left-sided lesions and may be considered on an individual basis for systemic right ventricle and single-ventricle patients. Medical therapy is limited for HFpEF. However, in both HFrEF and HFpEF, ventricular dyssynchrony and arrhythmias play an important role, and medications for rhythm control, ablation, and cardiac resynchronization therapy should be considered. Finally, aggressive management of cardiovascular risk factors and comorbidities, including, but not limited to, hypertension, obesity, diabetes, dyslipidemia, and obstructive sleep apnea, cannot be overemphasized.

Left bundle branch area pacing in congenitally corrected transposition of great arteries - The obvious choice?

Patients with congenitally corrected transposition of the great arteries (CCTGA) are susceptible to acquired atrioventricular conduction disease in early life. Emerging studies propose that conduction system pacing either by His bundle pacing or bundle branch pacing is advantageous in this population. The anatomical abnormality of CCTGA conveniently positions the left bundle branches on the easily accessible right ventricular septal side. We present a case of a young female CCTGA patient with exercise-induced heart block who received left bundle branch area pacing with the ventricular lead implanted at the conventional right ventricular septal approach without the need for 3-dimensional electroanatomical mapping.

Performance of epimyocardial leads in patients with a single ventricle circulation

BACKGROUND

Cardiac pacing can be challenging after a Fontan operation, and limited data exist regarding strategies to plan these epimyocardial systems while minimizing the number of surgical procedures.

METHODS

A retrospective review of all our 47 patients (mean age 18 years, standard deviation 9 years) with a Fontan palliation who received an epimyocardial cardiac implantable electronic device (CIED) between 2002 and 2020 with regard to the stability of the epimyocardial lead parameters and the incidence of system revisions.

RESULTS

Over the last 18 years, 84 implantations or revisions of the epimyocardial CIED in 47 Fontan patients were performed. Mean age at time of the first implantation was 9.4 (range 0.28-29.3) years. Follow-up period ranges from 0.11 to 18.2 (mean 7.7, standard deviation 4.2) years. A total of 123 pacing leads were implanted of which 99 are still active. From 2010 triple lead cardiac resynchronization devices were used in 17 patients to better cope with lead problems. The initial pacing threshold of the leads inactivated during this study period proved significantly higher (mean 1.66 V) than in the "all leads" group (mean 1.27 V, p = .0005) or the group of the still active leads (mean 1.17 V, p = .00004).

CONCLUSIONS

When implanted with a low pacing threshold, the bipolar epimyocardial electrodes show stable and good long-term results in young patients with a Fontan circulation. Resynchronization pacing systems and the prospective implantation of reserve leads may help to reduce the rate of resternotomies and provide a flexible concept to deal with lead failure.

Long-Term Outcome of Patients With Congenital Heart Disease Undergoing Cardiac Resynchronization Therapy

Background

Cardiac resynchronization therapy (CRT) is rarely used in patients with congenital heart disease, and reported follow‐up is short. We sought to evaluate long‐term impact of CRT in a single‐center cohort of patients with congenital heart disease.

Methods and Results

Thirty‐two consecutive patients with structural congenital heart disease (N=30) or congenital atrioventricular block (N=2), aged median of 12.9 years at CRT with pacing capability device implantation, were followed up for a median of 8.7 years. CRT response was defined as an increase in systemic ventricular ejection fraction or fractional area of change by >10 units and improved or unchanged New York Heart Association class. Freedom from cardiovascular death, heart failure hospitalization, or new transplant listing was 92.6% and 83.2% at 5 and 10 years, respectively. Freedom from CRT complications, leading to surgical system revision (elective generator replacement excluded) or therapy termination, was 82.7% and 72.2% at 5 and 10 years, respectively. The overall probability of an uneventful therapy continuation was 76.3% and 58.8% at 5 and 10 years, respectively. There was a significant increase in ejection fraction/fractional area of change (P<0.001) mainly attributable to patients with systemic left ventricle (P=0.002) and decrease in systemic ventricular end‐diastolic dimensions (P<0.05) after CRT. New York Heart Association functional class improved from a median 2.0 to 1.25 (P<0.001). Long‐term CRT response was present in 54.8% of patients at last follow‐up and was more frequent in systemic left ventricle (P<0.001).

Conclusions

CRT in patients with congenital heart disease was associated with acceptable survival and long‐term response in ≈50% of patients. Probability of an uneventful CRT continuation was modest.

Pacing-associated cardiomyopathy in adult congenital heart disease

Objectives

Long-term single-site ventricular pacing may adversely affect ventricular function, due to dyssynchronous systemic ventricular contraction. We sought to determine the incidence, predictors and outcomes of pacing-associated cardiomyopathy (PACM) in an adult congenital heart disease (ACHD) cohort.

Methods

We retrospectively identified all patients in our database with a permanent pacemaker from 2000 to 2019. Patients were followed for the primary endpoint of unexplained decline in systemic ventricular function (PACM) and the secondary endpoint of heart failure admission.

Results

Of 2073 patients in our database, 106 had undergone pacemaker implantation. Over a median follow-up of 9.4 years, 25 patients (24%) developed PACM, but only in those with ventricular pacing percentage (VP%) ≥70%; PACM occurred in 0% of those with VP <70% and 47% of those with VP ≥70% (p<0.001). High-burden ventricular pacing (≥70%) remained predictive of PACM in transposition of the great arteries, tetralogy of Fallot and complex biventricular repair subgroups, but not in Fontan patients. Those with PACM were more likely to be admitted with heart failure (44% vs 15%, p=0.002). Cardiac resynchronisation therapy (CRT) upgrade was performed in 11 patients, with 9 responders (82%).

Conclusions

In a cohort of patients with ACHD followed long-term post-pacing, 24% developed cardiomyopathy that was significantly associated with a higher burden of ventricular pacing (VP ≥70%). Given promising response rates to CRT, patients with ACHD expected to pace in the ventricle should be closely monitored for systemic ventricular decline.

Cardiac resynchronization therapy improves the ventricular function of patients with Fontan physiology

Past studies have not detected consistent improvement in ventricular function (VFxn) following initiation of cardiac resynchronization therapy (CRT) in Fontan patients. However, these studies used qualitative assessments of VFxn and/or quantitative assessments of VFxn that rely upon anatomic and/or geometric assumptions that may not be valid in patients with single ventricles. To address this, we used quantitative indices of global VFxn (dP/dt_ic and the Tei index) that are not encumbered by the limitations associated with the indices used in previous studies of CRT in Fontan patients.

METHODS

Patients with Fontan physiology who had received CRT therapy from 2004 to 2019 were included in the study. They were compared to a concurrent group of Fontan patients who had received standard dual-chamber pacemakers (DCPMs).

RESULTS

VFxn was assessed at 3 time points: prior to, shortly after, and late after initiation of pacemaker therapy. Prior to initiation of pacemaker therapy, VFxn of the CRT patients tended to be worse than that of the DCPM patients. For both groups, VFxn appeared to be stable or slightly improved shortly after initiation of pacemaker therapy. In the CRT group, VFxn improved significantly between early and late follow-up. In contrast, VFxn in DCPM patients tended to decline during this period. Changes in VFxn correlated with concurrent changes in New York Heart Association classification.

CONCLUSIONS

Quantitative assessments of VFxn using indices not confounded by complex cardiac anatomy, segmental wall motions abnormalities, or inappropriate geometric assumptions revealed that CRT in Fontan patients is associated with preservation or improvement VFxn compared to standard DCPM. Changes in VFxn correlate with concurrent changes in New York Heart Association classification.

Cardiac resynchronization therapy for the failing systemic right ventricle: A systematic review

Patients with a systemic right ventricle (SRV) are at high risk for development of heart failure early in life. An SRV is encountered in patients with congenitally corrected transposition of the great arteries (CCTGA) or dextro-transposition of the great arteries (DTGA) with previous atrial switch repair (Mustard or Senning procedure). Progressive heart failure is one of the leading cause of mortality in these patients. Therefore, cardiac resynchronization therapy (CRT) has gained increasing momentum for use in this challenging congenital heart disease (CHD) population. However, current guidelines differ in recommendations for CRT in patients with an SRV as evidence supporting CRT has thus far only been described in case reports and retrospectively in relatively small study populations. In fact, the European Society of Cardiology Guideline for the management of grown-up congenital heart disease consider CRT to be 'experimental' in this population. This systematic review critically summarizes current literature on CRT in SRV patients and provides future perspectives for further research in this challenging and growing CHD population.

Cardiomyopathies in children: classification, diagnosis and treatment

PURPOSE OF REVIEW

Cardiomyopathies are rare in the pediatric population, but significantly impact on morbidity and mortality. The present review aims to provide an overview of cardiomyopathies in children and some practical guidelines for their prognostic stratification and management.

RECENT FINDINGS

Pediatric cardiomyopathies may present as isolated cardiac muscle disease or in the context of complex clinical syndromes. The etiologic characterization represents an important step in the diagnosis and treatment of cardiomyopathies because of its impact on prognosis and on therapeutic measures. Indeed, replacement therapy is nowadays widely available and changes the natural history of the disease. More complex is the management of isolated cardiomyopathies, which lack specific therapies, mainly aimed at symptomatic relief. In this context, heart transplantation shows excellent outcomes in children, but wait-list mortality is still very high. Device therapy for sudden cardiac death prevention and the use of mechanical assist devices are becoming more common in the clinical practice and may help to reduce mortality.

SUMMARY

Providing insight into pediatric cardiomyopathies classification helps in the prognostication and management of such diseases. Recent years witnessed a significant improvement in mortality, but future research is still needed to improve quality of life and life expectations in the pediatric population.

Right ventricular septal pacing via transmural approach for resynchronization in a child with postoperative heart block

An infant with transposition of the great arteries was paced for postoperative heart block (single-site, right ventricular [RV] epicardial). She developed severe left ventricular (LV) dysfunction and septal dyskinesis. Resynchronization was performed at the age of 4 with an LV epicardial lead and an RV septal endocardial lead. The endocardial lead was affixed to the interventricular septum, then tunneled through the RV free wall and attached to an abdominal pulse generator. QRS duration decreased (176 to 122 ms) and LV ejection fraction improved (26 to 61%) and remained stable for 8 years. We present a case of successful resynchronization in congenital heart disease using a transmural RV septal lead.

Adults with Congenital Heart Disease and Arrhythmia Management

Arrhythmia management in adult congenital heart disease (ACHD) encompasses a wide range of problems from bradyarrhythmia to tachyarrhythmia, sudden death, and heart failure-related electrical dyssynchrony. Major advances in the understanding of the pathophysiology and treatments of these problems over the past decade have resulted in improved therapeutic strategies and outcomes. This article attempts to define these problems and review contemporary management for the patient with ACHD presenting with cardiac arrhythmia.

Permanent His-bundle Pacing in Pediatrics and Congenital Heart Disease

Permanent His-bundle pacing has been gaining popularity in the adult population requiring cardiac resynchronization therapy. Initial procedural challenges are being overcome, and this method of pacing has been shown to improve left ventricular function and heart failure symptoms secondary to ventricular dyssynchrony. Though the etiologies of ventricular dyssynchrony may differ in children and those with congenital heart disease than in adults with structurally normal hearts, His-bundle pacing may also be a preferred option in these groups to restore more physiologic electric conduction and improve ventricular function. We present a review of the current literature and suggested directions involving deploying permanent His-bundle pacing in the pediatric and congenital heart disease population.

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.

Early and Late Effects of Cardiac Resynchronization Therapy in Adult Congenital Heart Disease

Background

There are limited data about cardiac resynchronization therapy (CRT) in adult congenital heart disease. We aimed to assess early and late outcomes of CRT among patients with adult congenital heart disease.

Methods and Results

We retrospectively studied 54 patients with adult congenital heart disease (median age, 46 years; range, 18–73 years; 74% men) who received CRT implantation (biventricular paced >90%) between 2004 and 2017. Clinical and echocardiographic data were analyzed at baseline and early (mean±SD: 1.8±0.8 years) and late (4.7±0.8 years) follow‐up after CRT. Compared with baseline, CRT was associated with significant improvement at early follow‐up in New York Heart Association functional class, QRS duration, and cardiothoracic ratio (P<0.05 for all); improvement in New York Heart Association class was sustained at late follow‐up. Among patients with a systemic left ventricle (LV; n=39), there was significant increase in LV ejection fraction and reduction in LV end‐systolic volume at early and late follow‐up (P<0.05 for both). For patients with a systemic right ventricle (n=15), there was a significant early but not late reduction in systemic right ventricular basal and longitudinal diameters. Eleven patients died, and 2 had heart transplantation unrelated to systemic ventricular morphological characteristics. Thirty‐five patients (65%) responded positively to CRT, but only baseline QRS duration was predictive of a positive response.

Conclusions

CRT results in sustained improvement in functional class, systemic LV size, and function. Patients with a systemic LV and prolonged QRS duration, independent of QRS morphological characteristics, were most likely to respond to CRT.

Clinical impact of cardiac computed tomography derived three-dimensional strain for adult congenital heart disease: a pilot study

To assess ventricular function and dyssynchrony using three-dimensional (3D) computed tomography (CT) strain in adult congenital heart disease (ACHD). We prospectively analyzed a multiphase cardiac CT data set for 22 adult patients with CHD, including 8 patients with congenital systemic right ventricle (RV) and 14 patients with repaired Tetralogy of Fallot (TOF). Eight patients had a cardiac pacemaker. Volume of Interest was drawn on a multiplanar reconstruction of the ventricle with strain overlay using a 3D-strain algorithm. Ventricular strain, inter- and intraventricular dyssynchrony, and right ventricle outflow tract (RVOT)-apex dyssynchrony were calculated. RVOT-apex dyssynchrony by ventriculography was also compared in 15 patients. Pulmonary ventricular strain, systemic ventricular strain, and septal wall strain were lower in ACHD patients than in the controls, and lower in the ACHD with pacing group than without pacing group as well. Maximum interventricular time difference and intraventricular time difference were longer than in ACHD than in the controls, and longer in the ACHD with pacing group than without pacing group as well. RVOT-apex delay was significantly longer in patients with a pacemaker than in those without a pacemaker (118.1 ± 31.9 ms vs. 76.1 ± 36.2 ms, p = 0.03). RVOT delay determined by 3D CT strain significantly correlated with that determined by ventriculography (Pearson r = 0.55, p = 0.03). 3D CT strain can detect reduced biventricular contraction and inter- and intraventricular and RVOT-apex mechanical dyssynchrony can be assessed in patients with ACHD.

Successful staged tricuspid valve replacement following cardiac resynchronization therapy in a congenitally corrected transposition of the great arteries

Simple tricuspid valve surgery for complex heart disease with systemic right ventricular dysfunction is a high-risk procedure; however, staged tricuspid valve surgery following cardiac resynchronization therapy seems to be a beneficial method to expect reverse systemic ventricular remodeling.