Risk stratification in surgically repaired tetralogy of Fallot

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.

Recent advances in multimodal imaging in tetralogy of fallot and double outlet right ventricle

PURPOSE OF REVIEW

In the ever-evolving field of medical imaging, this review highlights significant advancements in preoperative and postoperative imaging for Tetralogy of Fallot (TOF) and double outlet right ventricle (DORV) over the past 18 months.

RECENT FINDINGS

This review showcases innovations in echocardiography such as 3D speckle tracking echocardiography (3DSTE) for assessing right ventricle-pulmonary artery coupling (RVPAC) and Doppler velocity reconstruction (DoVeR) for intracardiac flow fields evaluation. Furthermore, advances in assessment of cardiovascular anatomy using computed tomography (CT) improve the integration of imaging in ablation procedures. Additionally, the inclusion of cardiac magnetic resonance (CMR) parameters as risk score predictors for morbidity, and mortality and for timing of pulmonary valve replacement (PVR) indicates its significance in clinical management. The utilization of 4D flow techniques for postoperative hemodynamic assessment promises new insights into pressure mapping. Lastly, emerging technologies such as 3D printing and 3D virtual reality are expected to improve image quality and surgical confidence in preoperative planning.

SUMMARY

Developments in multimodality imaging in TOF and DORV are poised to shape the future of clinical practice in this field.

Repaired Tetralogy of Fallot: Have We Understood the Right Timing of PVR?

Despite many advances in surgical repair during the past few decades, the majority of tetralogy of Fallot patients continue to experience residual hemodynamic and electrophysiological abnormalities. The actual issue, which has yet to be solved, is understanding how this disease evolves in each individual patient and, as a result, who is truly at risk of sudden death, as well as the proper timing of pulmonary valve replacement (PVR). Our responsibility should be to select the most appropriate time for each patient, going above and beyond imaging criteria used up to now to make such a clinically crucial decision. Despite several studies on timing, indications, procedures, and outcomes of PVR, there is still much uncertainty about whether PVR reduces arrhythmia burden or improves survival in these patients and how to appropriately manage this population. This review summarizes the most recent research on the evolution of repaired tetralogy of Fallot (from adolescence onwards) and risk factor variables that may favor or delay PVR.

The Role of Cardiopulmonary Testing to Risk Stratify Tetralogy of Fallot Patients

Neonatal repair has completely changed the clinical history of patients with tetralogy of Fallot (ToF); however, these patients carry a significant risk of severe arrhythmias and sudden cardiac death in the long term. The exact mechanism for late sudden cardiac death is multifactorial and still not well defined, and the risk stratification for primary prophylaxis in these patients remains challenging. Cardiopulmonary exercise testing (CPET) is a well-established and safe method to assess cardiopulmonary function in children and adults with congenital heart disease. Several parameters obtained with CPET have been identified as potential prognostic of major adverse cardiovascular events in congenital heart disease. CPET is routinely used to assess functional capacity also in patients with ToF, and there is some evidence showing its usefulness in predicting the cardiac adverse events in patients with repaired ToF. Current guidelines recognize the importance of CPET in the evaluation and management of patients with ToF, but there is no clear consensus on which the CPET parameter or level of exercise intolerance, as measured by CPET, is truly predictive of an increased risk of arrhythmia and major adverse cardiovascular events in this population. Therefore, the aim of this narrative review is to describe the current evidence on the potential use of CPET in the risk stratification of patients with repaired ToF.

Ventricular Arrhythmias in Adults With Congenital Heart Disease, Part I: JACC State-of-the-Art Review

Patients with congenital heart disease associated with a higher risk for ventricular arrhythmias (VA) and sudden cardiac death (SCD) can be divided conceptually into those with discrete mechanisms for reentrant monomorphic ventricular tachycardia (VT) (Group A) and those with more diffuse substrates (Group B). Part I of this review addresses Group A lesions, which predominantly consist of tetralogy of Fallot and related variants. Well-defined anatomic isthmuses for reentrant monomorphic VT are interposed between surgical scars and the pulmonary or tricuspid annulus. The most commonly implicated critical isthmus for VT is the conal septum that divides subpulmonary from subaortic outlets. Programmed ventricular stimulation can be helpful in risk stratification. Although catheter ablation is not generally considered an alternative to the implantable cardioverter-defibrillator (ICD) for prevention of SCD, emerging data suggest that there is a subset of carefully selected patients who may not require ICDs after successful monomorphic VT ablation.

The value of myocardial strain imaging in the evaluation of patients with repaired Tetralogy of Fallot: a review of the literature

Tetralogy of Fallot (ToF) is considered to be the most common, complex, cyanotic congenital heart disease (CHD) representing 7-10% of all congenital heart defects, whereas the patients with ToF are the most frequently operated in their early infancy or childhood. Cardiac magnetic resonance (CMR) consists a valuable imaging technique for the diagnosis and serial follow-up of CHD patients. Furthermore, in recent years, advanced echocardiography imaging techniques have come to the fore, aiming to achieve a complete and more accurate evaluation of cardiac function using speckle tracking imaging modalities. We conducted a review of the literature in order to assess the myocardial deformation of patients with repaired ToF (rToF) using echocardiographic and CMR parameters. Patients with rToF have impaired myocardial strain parameters, that are well standardized either with the use of speckle tracking echocardiography or with the use of CMR imaging. Subclinical left ventricular dysfunction (low GLS) and myocardial dyssynchrony are commonly identified in rToF patients. Impaired left atrium (LA) and right atrium (RA) mechanics are, also, a common finding in this study population, but the studies using atrial strain are a lot fewer than those with LV and RV strain. No studies using myocardial work were identified in the literature, as far as rToF patients are concerned, which makes it an ideal field for further investigation.

Ventricular arrhythmias following transcatheter pulmonary valve replacement with the harmony TPV25 device

BACKGROUND

Transcatheter pulmonary valve replacement (TPVR) with the Harmony valve (Medtronic, Inc.) was recently approved to treat postoperative native outflow tract pulmonary regurgitation. While the 22 mm Harmony valve Early Feasibility Study demonstrated ventricular tachycardia (VT) in only 5% of patients, little is known about ventricular arrhythmias after TPVR with the larger 25 mm valve (TPV25).

METHODS

A single center review was performed of patients with TPV25 implant from 2020 to 2021. Demographic, cardiac, procedural, and postimplant cardiac telemetry data were collected and compared between patients who did and did not have peri-implant ventricular arrhythmia.

RESULTS

Thirty patients underwent TPV25 at a median age of 30 years. On postimplant telemetry, VT events were documented in 12 patients (40%); 11 nonsustained VT (NSVT) (median 3 episodes per patient and 6 beats per episode, maximum 157 episodes) and 1 sustained VT (3%), with Torsades de Pointes secondary to a short coupled premature ventricular contraction (PVC). VT events were associated with annular valve positioning (p < 0.001) and increased postimplant PVC burden (p < 0.0001), but there was no association between VT and other demongraphic, historical, or procedural factors. The frequency of NSVT events fell from 3/h from 0 to 12 h postimplant to 0.5/hr from 12 to 24 h (p < 0.001).

CONCLUSION

VT occurred commonly (40%) in the first 24 h after TPV25 implant, with self-limited NSVT in 11 of 12 patients and 1 patient with cardiac arrest secondary to Torsades de Pointes. VT only occurred with annular valve positioning. Larger, longer-term studies are needed to determine risk factors for and natural history of post-TPVR VT.

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.

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: 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.

Study of the time-relationship of the mechano-electrical interaction in an animal model of tetralogy of Fallot: implications for the risk assessment of ventricular arrhythmias

OBJECTIVES

The long-term outcome of tetralogy of Fallot (TOF) is determined by progressive right ventricular (RV) dysfunction through pulmonary regurgitation (PR) and the risk of malignant arrhythmia. Although mechano-electrical coupling in TOF is well-known, its time effect on the inducibility of arrhythmia remains ill-defined. The goal of this study was to investigate the mechano-electrical properties at different times in animals with chronic PR.

METHODS

PR was induced by a transannular patch with limited RV scarring in infant pigs. Haemodynamic assessment included biventricular pressure-volume loops after 3 (n = 8) and 6 months (n = 7) compared to controls (n = 5). The electrophysiological study included endocardial monophasic action potential registration, intraventricular conduction velocity and induction of ventricular arrhythmia by burst pacing.

RESULTS

Progressive RV dilation was achieved at 6 months (RV end-diastolic volume 143 ± 13 ml/m2-RV end-systolic volume 96 ± 7 ml/m2; P < 0.001), in association with depressed RV contractility (preload recruitable stroke work-slope: 19 ± 1 and 11 ± 3 Mw.ml-1.s-1 for control and 6 m; P < 0.001) and left ventricular contractility (preload recruitable stroke work-slope: 60 ± 13 and 40 ± 11 Mw.ml-1.s-1 for control and 6 m; P = 0.005). Concomitant to QRS prolongation, monophasic action potential90-duration and dispersion at the RV and left ventricle were increased at 6 months. Intraventricular conduction was delayed only in the RV at 6 months (1.8 ± 0.2 and 2.4 ± 0.6 m/s for group 6M and the control group; P = 0.035). Sustained ventricular arrhythmias were not inducible.

CONCLUSIONS

In animals yielding the sequelae of a contemporary operation for TOF, mechano-electrical alterations are progressive and affect predominantly the RV after midterm exposure of PR. Because ventricular arrhythmias were not inducible despite significant RV dilation, the data suggest that the haemodynamic RV deterioration effectively precedes the risk of inducing sustained arrhythmia after TOF repair and opens a window for renewed stratification of contemporary risk factors of ventricular arrhythmias in patients operated on with currently used pulmonary valve- and RV-related techniques.

Prognostic markers in patients undergoing transcatheter implantation of Venus P-valve: Experience in Taiwan

BACKGROUND/PURPOSE

Prognostic factors remain unclear in patients undergoing transcatheter implantation of Venus P-valve for their severe pulmonary regurgitation associated with native right ventricular (RV) outflow tract.

METHOD

Between January 2017 and October 2018, we prospectively collected data of patient characteristics, cardiac magnetic resonance imaging, cardiopulmonary exercise testing, and levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) before and 6-12 months after valve graft implantation.

RESULTS

Fifteen patients (male: 8, median age: 24.8 years) were enrolled. The procedure success rate was 100%. The median follow-up was 16.3 months without any dysfunction of the valve graft. The cohort demonstrated a significant improvement in cardiac index (from 3.3 to 3.9 L/min/m²) and increase of percentage of New York Heart Association functional class I (P < 10^-3), reduction in RV end-diastolic volume index (P = 0.008), and reductions in NT-proBNP levels (from 78.9 to 45.8 pg/mL, P = 0.040). However, the peak oxygen consumption (VO₂) dropped from 50.2% to 48.5% of the predicted value. Interestingly, we determined that patients with NT-proBNP levels below 70 pg/mL and left ventricular end-diastolic pressure (LVEDP) below 11 mmHg had a significantly higher chance of exhibiting improvement in peak VO₂ compared with those without (3/4 vs 1/10, P = 0.041).

CONCLUSION

In the small cohort with severe pulmonary regurgitation, implantation of a Venus P-valve led to promising reductions in RV volume. However, no definite improvement in cardiopulmonary exercise capacity or RV ejection fraction was achieved. Levels of NT-proBNP and LVEDP may be helpful for refining the indications of the Venus P-valve implantation.

Challenges in Ablation of Complex Congenital Heart Disease

The field of congenital cardiac electrophysiology is growing rapidly due to the rapid growth in the population of survivors of childhood critical congenital heart disease surgery. Chronic arrhythmias pose one of the biggest challenges in this patient population, and catheter ablation, despite its challenges, is still the most desirable and acceptable approach when successful. Clinicians who propose catheter ablation in such patients need to understand the congenital anatomy, should carefully review the details of all prior cardiac surgery, and should be prepared to deal with the various challenges posed by lack of normal cardiac access and the possibility of poor hemodynamics. Still, experienced laboratories can achieve excellent results in this difficult patient population.

The outcome of adults born with pulmonary atresia: High morbidity and mortality irrespective of repair

OBJECTIVES

To describe the characteristics and long-term outcome of a large adult cohort with pulmonary atresia.

BACKGROUND

Patients with pulmonary atresia (PA) are a heterogeneous population in terms of anatomy, physiology and surgical history, and their management during adulthood remains challenging.

METHODS

Data on all patients with PA followed in our center between January 2000 and March 2015 were recorded. Patients were classified into the following groups: PA with ventricular septal defect (PA-VSD, 1), PA with intact ventricular septum (PA-IVS, 2) and other miscellaneous PA (PA-other, 3).

RESULTS

Two-hundred twenty-seven patients with PA were identified, 66.1% female, mean age 25.5 ± 8.7 years. Over a median follow-up of 8.8 years, 49 (21.6%) patients had died: heart failure (n = 21, 42.8%) and sudden cardiac death (n = 8, 16.3%) were the main causes. There was no significant difference in mortality between the 3 Groups (p = 0.12) or between repaired and unrepaired patients in Group 1 (p = 0.16). Systemic ventricular dysfunction and resting oxygen saturations were the strongest predictors of mortality. Additionally, 116 (51%) patients were hospitalized, driven mainly by the need for invasive procedures, heart failure and arrhythmias.

CONCLUSIONS

Adult survivors with pulmonary atresia have a high morbidity and mortality irrespective of underlying cardiac anatomy and previous reparative or palliative surgery. We present herewith predictors of outcome in adult life that may assist with their tertiary adult congenital care.

EDUCATIONAL SERIES IN CONGENITAL HEART DISEASE: Tetralogy of Fallot: diagnosis to long-term follow-up

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect, affecting 3 in 10,000 live births. Surgical correction in early childhood is associated with good outcomes, but lifelong follow-up is necessary to identify the long-term sequelae that may occur. This article will cover the diagnosis of TOF in childhood, the objectives of surveillance through adulthood and the value of multi-modality imaging in identifying and guiding timely surgical and percutaneous interventions.

Multimodality imaging, single center, cross-sectional study in adolescents or young adults with repaired tetralogy of Fallout

BACKGROUND

Proper integration of multiple imaging modalities in the routine follow-up of patients with repaired tetralogy of Fallout (TOF) is poorly supported by data. We report our single center comparative study between cardiac magnetic resonance (CMR) and echocardiography to assess equipoise in the clinical utility of these two imaging methods in an unselected consecutive cohort of TOF patients referred to our outpatient clinic.

MATERIAL AND METHODS

In this cross-sectional study, repaired TOF patients who underwent CMR and echocardiography within a 4-week period between 2010 and 2011 at our Center were included. Linear regression was used to analyze degree of inter modality correlation. A prediction model tested the association between functional data/probrain natriuretic peptide (Pro-BNP) with CMR.

RESULTS

Fifty patients were included in the study (mean age 31 ± 18 years). The best predictors of right ventricle (RV) ejection fraction at CMR were tricuspid anular plane systolic excursion (tricuspid valve anular plane systolic excursion, R 0.37, P < 0.0001) and RV peak S-wave velocity (R 0.40, P < 0.001). Pro-BNP levels did present weak correlation with New York Heart Association functional class (R 0.31, P < 0.002) and QRS duration (R 0.32, P < 0.002) and a moderate correlation with right atrium area at CMR (R 0.46, P < 0.0001).

CONCLUSION

We found limited correlation between the two imaging modalities in the evaluation of RV after intracardiac repair of TOF. Pro-BNP level presents moderate correlation with right atrium area measured with echocardiography. Serial CMR evaluations are needed in this patient population, but they may be interchanged by routine echocardiography in particular in patients with normal or stable echocardiographic parameters.

Risk of cardiac tachyarrhythmia in patients with repaired tetralogy of Fallot: a multicenter cardiac MRI based study

Cardiac tachyarrhythmias are the leading cause of morbidity and mortality in patients with repaired tetralogy of Fallot (TOF). We evaluated risk factors for sustained ventricular tachyarrhythmia (VT) and atrial tachyarrhythmia (ATA) in these patients. Patients (n = 319) who underwent cardiac magnetic resonance (CMR) imaging at two tertiary centers between 2007 and 2016 were assessed. Potential risk markers, based on history, cardiac magnetic resonance imaging (CMR), electrocardiography (ECG) and echocardiography, were analyzed for prediction of the primary endpoint of VT, and the secondary endpoint of ATA. During a follow-up of 3.5 (0.9-6.1) years, 20 (6.3%) patients reached the primary endpoint, and 30 (9.4%) the secondary endpoint. Multivariable cox hazards regression identified right ventricular (RV) end-diastolic volume (Hazard ratio [HR] 2.03, per 10 ml/m² increase; p = 0.02), RV end-systolic volume (HR 3.04, per 10 ml/m² increase; p = 0.04), RV mass (HR 1.88, per 10 g/m² increase; p = 0.02), and RV ejection fraction (HR 6.06, per 10% decrease; p = 0.02) derived from CMR to be independent risk factors of VT. In addition, QRS-duration (HR 1.70, per 10 ms increase; p = 0.001) and body mass index (BMI: HR 1.8, per 5 kg/m² increase; p = 0.02) were independent markers of VT. Older age at TOF repair (HR 1.33, per 2 months increase; p = 0.03) and BMI (HR 1.76, per 5 kg/m² increase; p < 0.001) independently predicted ATA. RV systolic dysfunction, hypertrophy and dilatation on CMR, together with QRS prolongation, and obesity are predictive of VT in TOF patients. Older age at TOF repair and obesity were associated with the occurrence of ATA.

Biventricular dyssynchrony on cardiac magnetic resonance imaging and its correlation with myocardial deformation, ventricular function and objective exercise capacity in patients with repaired tetralogy of Fallot

BACKGROUND

Electrical dyssynchrony and prolonged QRS duration are common in patients with repaired tetralogy of Fallot (ToF). It has been linked to increased risk of sudden cardiac death and right ventricular (RV) dysfunction. We investigated myocardial dyssynchrony using cardiac magnetic resonance imaging (CMR) and feature tracking analysis (FT) in this setting and compared it to myocardial deformation, conventional parameters of ventricular dysfunction and clinical parameters.

METHODS AND RESULTS

Patients underwent standardized CMR investigations as part of a nationwide study. We prospectively assessed myocardial deformation and analysed regional wall motion abnormalities of the RV and the left ventricle (LV) using CMR-FT. The main measure of dyssynchrony was the maximal time difference (wall motion delay) of the regional strain as a parameter of mechanical biventricular dyssynchrony. In addition, clinical parameters and measures of cardiopulmonary exercise capacity were available. Overall 345 patients were included. Parameters of biventricular wall motion delay correlated significantly with global FT-strain parameters (p < 0.0001 for all imaging planes assessed). Furthermore, we found a significant correlation between circumferential RV motion delay and QRS duration (p = 0.006). Higher LV and RV wall motion delay parameters were also associated with lower peak oxygen consumption (p < 0.05) and a worse LV and RV ejection fraction (p < 0.02).

CONCLUSIONS

Assessment of mechanical dyssynchrony is feasible using CMR-FT in ToF patients. Parameters of mechanical dyssynchrony correlate with electrical dyssynchrony, biventricular function and objective exercise capacity in this setting. Due to the weak degree of correlation, however, the clinical significance of these findings remains to be clarified by further studies.

The Role of Cardiopulmonary Exercise Testing for Decision Making in Patients with Repaired Tetralogy of Fallot

Tetralogy of Fallot is the most common form of cyanotic congenital heart disease. As a result of the surgical strategies employed at the time of initial repair, chronic pulmonary regurgitation (PR) is prevalent in this population. Despite sustained research efforts, patient selection and timing of pulmonary valve replacement (PVR) to address PR in young asymptomatic patients with repaired tetralogy of Fallot (rToF) remain a fundamental but as yet unanswered question in the field of congenital heart disease. The ability of the heart to compensate for the chronic volume overload imposed by PR is critical in the evaluation of the risks and benefits of PVR. The difficulty in clarifying the functional impact of PR on the cardiovascular capacity may be in part responsible for the uncertainty surrounding the timing of PVR. Cardiopulmonary exercise testing (CPET) may be used to assess abnormal cardiovascular response to increased physiologic demands. However, its use as a tool for risk stratification in asymptomatic adolescents and young adults with rToF is still ill-defined. In this paper, we review the role of CPET as a potentially valuable adjunct to current risk stratification strategies with a focus on asymptomatic rToF adolescents and young adults being considered for PVR. The role of maximal and submaximal exercise measurements to identify young patients with a decreased or borderline low peak VO₂ resulting from impaired ventricular function is explored. Current knowledge gaps and research perspectives are highlighted.

Ventricular Arrhythmias in Adult Congenital Heart Disease: Mechanisms, Diagnosis, and Clinical Aspects

The risk of ventricular arrhythmias in the adult congenital heart disease population increases with age. The mechanism, type, and frequency vary depending on the complexity of the defect, whether it has been repaired, and the type and timing of repair. Risk stratification for sudden death in patients with congenital heart disease is often challenging. Current recommendations provide a useful guide for management of these patients and risk stratification continues to evolve. Internal cardiac defibrillator implantation is often challenging due to limited transvenous access, often resulting in the need for epicardial or subcutaneous devices.

Myocardial deformation parameters predict outcome in patients with repaired tetralogy of Fallot

BACKGROUND

Parameters of myocardial deformation have been suggested to be superior to conventional measures of ventricular function and to predict outcome in repaired tetralogy of Fallot (ToF). We aimed to test the hypothesis that parameters of myocardial deformation on cardiac MRI (CMR) relate to symptoms and provide prognostic information in patients with repaired ToF.

METHODS AND RESULTS

We included 372 patients with ToF (median age 16 years; 55% male), recruited within a nationwide, prospective study. Longitudinal (LS), circumferential (CS) and radial global strain (RS) were analysed by CMR-based feature tracking (FT). A combined endpoint of death, successful resuscitation or documented ventricular tachycardia was employed. Parameters of global strain were associated with New York Heart Association (NYHA) class and symptomatic deterioration. During a median follow-up of 7.4 years, 20 events occurred. Left ventricular (LV) CS and right ventricular (RV) LS emerged as predictors of outcome, independent of QRS duration, LV/RV ejection fraction and volumes, NYHA class and peak oxygen uptake. In combination, these parameters also identified a subgroup of patients at significantly increased risk of adverse of outcomes (HR 3.3, p=0.002). Furthermore, LV LS, RS, CS and RV LS were related to the risk of death and nearly missed death (p<0.05 for all).

CONCLUSIONS

FT-CMR provides myocardial deformation parameters, easily derived from standard CMR studies. They relate to symptoms and clinical deterioration in patients with ToF. More importantly, they predict adverse outcome independent of established risk markers, and should be considered as a useful adjunct to established outcome predictors, especially in younger patients with ToF.

CLINICAL TRIAL REGISTRATION NUMBER

http://www.clinicaltrials.gov: NCT00266188; Results.

Impact of clinical follow-up and diagnostic testing on intervention for tetralogy of Fallot

Objective

Our purpose was to evaluate yield of tools commonly advocated for surveillance of tetralogy of Fallot (TOF).

Methods

All patients (pts) with TOF, seen at any time from 1/2008 to 9/2013 in an academic cardiology practice were studied. At the first and each subsequent outpatient visit, the use of tools including history and physical (H&P), ECG, Holter (HOL), echocardiogram (Echo), MR or CT (MR-CT) and stress testing (STR) were noted. Recommendations for intervention (INT) and for time to next follow-up were recorded; rationale for each INT with attribution to one or more tools was identified.

Results

There were 213 pts (mean 11.5 years, 130 male) who had 916 visits, 123 of which (13.4%) were associated with 138 INTs (47 surgical, 54 catheter-mediated, 37 other medical). Recommended follow-up interval was 9.44±6.5 months, actual mean follow-up interval was 11.7 months. All 916 (100%) patient visits had a H&P which contributed to 47.2% of INT decisions. Echo was performed in 652 (71.2%) of visits, and contributed to 53.7% of INTs. MR-CT was obtained in 129 (14.1%) of visits, and contributed to 30.1% of INTs. ECG was applied in 137 (15%) visits, and contributed to 1.6% of INTs. HOL was obtained in 188 (20.5%) visits, and contributed to 11.3% of INTs. STR was performed at 101 (11%) of visits, and contributed to 8.9% of INTs.

Conclusions

INTs are common in repaired TOF, but when visits average every 11–12 months, most visits do not result in INT. H&P, Echo and HOL were the most frequently applied screens, and all frequently yielded relevant information to guide INT decisions. STR and MR/CT were applied as targeted testing and in this limited, non-screening role had high relevance for INT. There was low utilisation of ECG and major impact on INT was not demonstrated. Risk stratification in TOF may be possible, and could result in more efficient surveillance and targeted testing.

Arrhythmias in Complex Congenital Heart Disease

Late after surgical repair of complex congenital heart disease, atrial arrhythmias are a major cause of morbidity, and ventricular arrhythmias and sudden cardiac death are a major cause of mortality. The six cases in this article highlight common challenges in the management of arrhythmias in the adult congenital heart disease population.

Pulmonic regurgitation and management challenges in the adult with tetralogy of fallot

OPINION STATEMENT

Patients with tetralogy of Fallot (TOF) are living longer than ever because of advances in surgery in childhood since the 1950s. However, surgery in childhood is not a cure and remains only a palliative procedure because almost all patients will require further intervention throughout life. The most common intervention required in adulthood is pulmonary valve replacement (PVR) because of residual pulmonary regurgitation leading to right ventricular dilation and eventual dysfunction. The most appropriate timing for PVR remains difficult to determine and is based on many factors. Our practice is to weigh not only objective factors such as right ventricular size and function but also careful objective assessment of the patient's current quality of life and functional status.