Optimal surgical ablation of atrial tachyarrhythmias during correction of Ebstein anomaly

Atrial Fibrillation Ablation in Congenital Heart Disease: Therapeutic Challenges and Future Perspectives

The increasing prevalence of atrial fibrillation (AF) in adults with congenital heart disease raises significant questions regarding its management. The unique underlying anatomic and physiological background further adds to the difficulty in eliminating the AF burden in these patients. Herein, we provide an overview of the current knowledge on the pathophysiology and risk factors for AF in adult congenital heart disease, with a special focus on the existing challenges in AF ablation. Emerging imaging modalities and ablation techniques might have a role to play. Evidence regarding the safety and efficacy of AF ablation in adult congenital heart disease is summarized, especially for patients with an atrial septal defect, Ebstein anomaly of the tricuspid valve, tetralogy of Fallot, and Fontan circulation. Finally, any remaining gaps in knowledge and potential areas of future research are highlighted.

Risk factors for atrial arrhythmia recurrence after atrial arrhythmia surgery with pulmonary valve replacement

Objectives

Atrial arrhythmias are a significant cause of late morbidity and mortality in patients after tetralogy of Fallot repair. However, reports on their recurrence following atrial arrhythmia surgery are limited. We aimed to identify the risk factors for atrial arrhythmia recurrence after pulmonary valve replacement (PVR) and arrhythmia surgery.

Methods

We reviewed 74 patients with repaired tetralogy of Fallot who underwent PVR for pulmonary insufficiency at our hospital between 2003 and 2021. Twenty-two patients (mean age, 39 years) underwent PVR and atrial arrhythmia surgery. A modified Cox-maze III was performed in 6 patients with chronic atrial fibrillation, and a right-sided maze was performed in 12 with paroxysmal atrial fibrillation, 3 with atrial flutter, and 1 with atrial tachycardia. Atrial arrhythmia recurrence was defined as any documented sustained atrial tachyarrhythmia requiring intervention. The influence of preoperative parameters on recurrence was assessed with the Cox proportional-hazards model.

Results

The median follow-up period was 9.2 years (interquartile range, 4.5-12.4). Cardiac death and redo-PVR due to prosthetic valve dysfunction were not observed. Eleven patients had atrial arrhythmia recurrence after discharge. Atrial arrhythmia recurrence-free rates were 68% at 5 years and 51% at 10 years after PVR and arrhythmia surgery. Multivariable analysis revealed that right atrial volume index (hazard ratio, 1.04; 95% confidence interval, 1.01-1.08, P = .009) was a significant risk factor for atrial arrhythmia recurrence after arrhythmia surgery and PVR.

Conclusions

Preoperative right atrial volume index was associated with atrial arrhythmia recurrence, which may assist in planning the timing of atrial arrhythmia surgery and PVR.

Non-Valvular Atrial Fibrillation in Young Adults in Eastern India: A Clinico-Aetiological Retrospective Analysis in a Tertiary Care Hospital

BACKGROUND

The development of atrial fibrillation adds a lot to the morbidity and mortality of individual patients. The spectrum of non-valvular atrial fibrillation among young adults is less known. The present observational study aims to analyze the clinical-aetiological spectrum of non-valvular atrial fibrillation among young adults between 18 and 40 years of age.

METHODS

A retrospective observational study was carried out to analyze the clinical-aetiological spectrum of non-valvular atrial fibrillation among young adults less than 40 years of age attending the cardiac outpatient department in a tertiary care hospital in Eastern India over a period of two years. Patients with any form of organic valvular heart disease and patients more than 40 years of age were excluded from the study. One hundred and seventeen patients under 40 years of age were analysed with respect to demographic, aetiological, and clinical profiles.

RESULTS

Most common aetiologies behind non-valvular atrial fibrillation in young adults (<40 years) were hypertension (40%) and the presence of left ventricular systolic dysfunction (31%). Thyrotoxicosis, obesity, obstructive sleep apnoea, the presence of congenital heart disease, coronary artery disease, myopericarditis, chronic kidney disease, dyselectronemia, diabetes mellitus, and the presence of chronic obstructive pulmonary disease contributed towards the development of non-valvular atrial fibrillation in the young population in less proportion of cases. Most of the cases were symptomatic with palpitation, shortness of breath, or diaphoresis. Less number of cases (17%) had left atrial thrombus which may be due to early clinical attention with the proper therapeutic anticoagulation regimen.

CONCLUSIONS

Hypertension and the presence of left ventricular systolic dysfunction contribute to the majority towards the development of non-valvular atrial fibrillation among young adults. Accurate measurement and monitoring of blood pressure among young adults and careful assessment of left ventricular systolic dysfunction with subsequent appropriate management of hypertension and left ventricular systolic dysfunction in young can decrease the burden of non-valvular atrial fibrillation among the young population.

Prognostic implications of atrial fibrillation in adults with Ebstein anomaly

OBJECTIVE

Supraventricular arrhythmias are common in adults with Ebstein anomaly (EA). However, there are limited data about prognostic implications of atrial fibrillation (AF) in this population. Accordingly, our aim was to assess the clinical profile and burden of AF in adults with EA, and the relationship between AF and outcomes.

METHODS AND RESULTS

Six hundred eighty-two consecutive adults with a median age of 36 (24-49) years from Mayo Clinic, Minnesota, USA, between 2003 and 2020 were included. Sustained episodes of AF, clinical, echocardiographic, rhythm and surgical data were collected. Prevalence of AF at baseline was 18% (126 patients); the first episode occurred at a mean age of 43±17 years. Patients with AF were older, were more likely men, and had hypertension, renal dysfunction, cardiac devices, and more advanced right-sided and left-sided remodelling. During a median follow-up of 156 (81-240) months, 62 patients (11%) developed incident AF. At the last encounter, prevalence of AF was 28% (188 patients); of those, 63 (34%) had recurrent AF. Hospitalisation for heart failure (HF) occurred in 51 patients (7%). AF (HR 2.32, 95% CI 1.18 to 4.47; p=0.01) was independently associated with hospitalisation for HF. All-cause death occurred in 53 patients (8%); it was more frequent in those with AF in the univariable analysis, although it did not remain significant in the multivariable analysis.

CONCLUSIONS

AF in EA develops at relatively young ages with one-third of the cohort exhibiting a recurrent pattern. Patients with AF had a higher prevalence of comorbidities and worse right-sided and left-sided cardiac remodelling. AF was independently associated with HF hospitalisation.

Neurological, Extracardiac, and Cardiac Manifestations of Ebstein's Anomaly Along With its Genetics, Diagnostic Techniques, Treatment Updates, and the Future Ahead

Ebstein's anomaly is a congenital heart defect characterized by the displacement of the tricuspid valve, and its leaflets to be malformed. Due to the defect involving the tricuspid valve, there is a reverse flow of blood into the right-sided atrium, which may lead to cardiac hypertrophy and edema of the lower extremities. There is a decreased flow of blood out of the right heart due to reduced right ventricular contractility and tricuspid regurgitation. Children afflicted with this anomaly usually suffer from atrial septal defect and this is usually diagnosed before birth on a routine ultrasound scan. In neonates, cyanosis can be seen due to right-to-left atrial shunting or as a result of severe congestive heart failure. If the infant has pulmonary hypertension, cyanosis is markedly increased as there will be a limitation in pulmonary blood flow. In adults, arrhythmias, cyanosis, and heart failure are seen. The bundle of Kent leads to the formation of an electrical conduction abnormality between the right ventricle and atrium. This leads to a condition commonly known as Wolff- Parkinson-White syndrome in patients. An enlarged spherical heart is usually present on a chest X-ray. ECG changes of Ebstein's anomaly show taller than usual P waves, PR prolongation, and right bundle branch block. There can be certain neurological and extracardiac manifestations too such as hemiplegia, stroke, dysarthria, etc. During fetal life, specifically at 16 and 20 weeks of gestation, the anomaly can be diagnosed via echocardiography. Prostaglandin infusion (PGE1) is given to maintain pulmonary circulation in neonates if cyanosis is seen. In children and adults with congestive cardiac failure due to this anomaly, medical management includes digoxin, beta-blockers, diuretics, and angiotensin converting enzyme (ACE) inhibitors to improve heart failure. Surgical treatment includes valve reconstruction. In this article, we review the pathophysiology, genetics, diagnosis, management, and prognosis of Ebstein's Anomaly along with a comprehensive discussion on its genetics, neurological manifestations, extracardiac features, and current advancements in treatment.

Atrial Flutters in Adults with Congenital Heart Disease

The macroreentrant atrial tachycardia is very frequent in the adults with congenital heart disease. The impact of the arrhythmias on this type of patients is related to several factors: the anatomy and physiopathology of the specific congenital heart disease (CHD), the sequelae of the corrective surgery or surgical palliation, the presence of residual lesions (shunt, regurgitation), and the age and the clinical status of the patient and the comorbidities. In turn, the mechanism of the MAT depends on the peculiar features of the conduction's system in the CHD and native and acquired (post-surgery) substrates.

Narrative review of Ebstein's anomaly beyond childhood: Imaging, surgery, and future perspectives

Ebstein's anomaly is a rare congenital heart disease with malformation of the tricuspid valve and myopathy of the right ventricle. The septal and inferior leaflets adhere to the endocardium due to failure of delamination. This leads to apical displacement of their hinge points with a shift of the functional tricuspid valve annulus towards the right ventricular outflow tract with a possibly restrictive orifice. Frequently, a coaptation gap yields tricuspid valve regurgitation and over time the "atrialized" portion of the right ventricle may dilate. The highly variable anatomy determines the clinical presentation ranging from asymptomatic to very severe with need for early operation. Echocardiography and magnetic resonance imaging are the most important diagnostic modalities to assess the tricuspid valve as well as ventricular morphology and function. While medical management of asymptomatic patients can be effective for many years, surgical intervention is indicated before development of significant right ventricular dilatation or dysfunction. Onset of symptoms and arrhythmias are further indications for surgery. Modified cone reconstruction of the tricuspid valve is the state-of-the-art approach yielding the best results for most patients. Alternative procedures for select cases include tricuspid valve replacement and bidirectional cavopulmonary shunt depending on patient age and other individual characteristics. Long-term survival after surgery is favorable but rehospitalization and reoperation remain significant issues. Further studies are warranted to identify the optimal surgical strategy and timing before adverse right ventricular remodeling occurs. It is this article's objective to provide a comprehensive review of current literature and an overview on the management of Ebstein's Anomaly. It focuses on imaging, cardiac surgery, and outcome. Additionally, a brief insight into arrhythmias and their management is given. The "future perspectives" summarize open questions and fields of future research.

Haemodynamic determinants of improved aerobic capacity after tricuspid valve surgery in Ebstein anomaly

BACKGROUND

Although tricuspid valve surgery improves functional capacity in patients with Ebstein anomaly, it is not always associated with improvement in aerobic capacity. The purpose of this study was to identify the determinants of improved aerobic capacity after tricuspid valve surgery in adults with Ebstein anomaly with severe tricuspid regurgitation.

METHODS

Retrospective study of patients with severe tricuspid regurgitation due to Ebstein anomaly that had tricuspid valve surgery at Mayo Clinic Rochester (2000-2019) and had preoperative and postoperative cardiopulmonary exercise tests and echocardiograms. The patients were divided into aerobic capacity(+) and aerobic capacity(-) groups depending on whether they had postoperative improvement in %-predicted peak oxygen consumption (VO2).

RESULTS

Of 76 patients with severe tricuspid regurgitation due to Ebstein anomaly, 28 (37%) and 48 (63%) were in aerobic capacity(+) and aerobic capacity(-) groups, respectively. The average improvement in peak VO2 was 2.1±1.4 mL/kg/min and -0.9±0.4 mL/kg/min in the in aerobic capacity(+) and aerobic capacity(-) groups, respectively. Although both groups had similar severity of residual tricuspid regurgitation, the aerobic capacity(+) group had more postoperative improvement in right atrial (RA) function, left atrial (LA) function and left ventricular preload and stroke volume. Of the preoperative variables analysed, RA reservoir strain (relative risk 1.12; 95% CI 1.06 to 1.18); LA reservoir strain (relative risk 1.09; 95% CI 1.04 to 1.14) and LV stroke volume index (OR 1.04; 95% CI 1.01 to 1.07) were predictors of postoperative improvement in peak VO2.

CONCLUSIONS

One-third of patients with severe tricuspid regurgitation due to Ebstein anomaly had postoperative improvement in aerobic capacity, and atrial function indices were the best predictors of postoperative improvement in aerobic capacity. These data provide new insight into the haemodynamic determinants of exercise capacity and lay the foundation for further studies to determine whether postoperative improvement in aerobic capacity translates to improved long-term survival, and whether timing of tricuspid valve surgery based on these echocardiographic indices will improve long-term outcomes.

Outcomes of Atrial Arrhythmia Surgery in Patients With Congenital Heart Disease: A Systematic Review

Background The improved life expectancy of patients with congenital heart disease is often accompanied by the development of atrial tachyarrhythmias. Similarly, the number of patients requiring redo operations is expected to continue to rise as these patients are aging. Consequently, the role of arrhythmia surgery in the treatment of atrial arrhythmias is likely to become more important in this population. Although atrial arrhythmia surgery is a well-established part of Fontan conversion procedures, evidence-based recommendations for arrhythmia surgery for macroreentrant atrial tachycardia and atrial fibrillation in other patients with congenital heart disease are still lacking. Methods and Results Twenty-eight studies were included in this systematic review. The median reported arrhythmia recurrence was 13% (interquartile range, 4%-26%) during follow-up ranging from 3 months to 15.2 years. A large variation in surgical techniques was observed. Based on the acquired data, biatrial lesions are more effective in the treatment of atrial fibrillation than exclusive right-sided lesions. Right-sided lesions may be more appropriate in the treatment of macroreentrant atrial tachycardia; evidence for the superiority of additional left-sided lesions is lacking. There are not enough data to support the use of exclusive left-sided lesions. Theoretically, prophylactic atrial arrhythmia surgery may be beneficial in this population, but evidence is currently limited. Conclusions To be able to provide recommendations for arrhythmia surgery in patients with congenital heart disease, future studies should report outcomes according to the type of preoperative arrhythmia, underlying congenital heart disease, lesion set, and energy source. This is essential for determining which surgical techniques should ideally be applied under which circumstances.

Ebstein Anomaly in the Adult Patient

Ebstein anomaly is a congenital malformation involving primarily the tricuspid valve, with failure of delamination from the underlying myocardium and right ventricular myopathy. Echocardiography is diagnostic in most patients and demonstrates apical displacement of the septal leaflet and variable tethering of leaflet tissue to the right ventricular myocardium. Operative intervention is considered for exertional symptoms, progressive right ventricular enlargement, or right ventricular dysfunction. Tricuspid valve cone repair is the preferred surgical approach. Tricuspid valve replacement and bidirectional cavopulmonary shunt also are considered in patients with advanced disease. Pregnancy generally is well tolerated. Patients with Ebstein anomaly require lifelong follow-up.

Ebstein's Anomaly

Ebstein's anomaly is a malformation of the tricuspid valve with myopathy of the right ventricle (RV) that presents with variable anatomic and pathophysiologic characteristics, leading to equally variable clinical scenarios. Medical management and observation is often recommended for asymptomatic patients and may be successful for many years. Tricuspid valve repair is the goal of operative intervention; repair also typically includes RV plication, right atrial reduction, and atrial septal closure or subtotal closure. Postoperative functional assessments generally demonstrate an improvement or relative stability related to degree of RV enlargement, RV dysfunction, RV fractional area change, and tricuspid valve regurgitation.

Improving Results of Surgery for Ebstein Anomaly: Where Are We After 235 Cone Repairs?

BACKGROUND

Ebstein anomaly has heterogeneous anatomy and numerous operative techniques are described. Cone repair provides a near anatomic tricuspid valve repair. The purpose of this study was to examine our experience with cone repair.

METHODS

Cone repair was performed in 235 consecutive patients with Ebstein anomaly, 134 children (57%) and 101 adults (43%), from June 2007 to October 2015. Median age was 15.6 years (range, 6 months to 73 years). Cone repair was the first operation in 192 patients (82%), the second in 41 (17%), and the third in 2 (1%). Previous tricuspid valve repair had been performed in 27 (12%). Echocardiograms were obtained preoperatively and at hospital dismissal for all patients and for a subgroup of patients at least 6 months after cone repair (n = 81).

RESULTS

Leaflet augmentation was done in 67 patients (28%), Sebening stitch in 57 (24.2%), neochordae in 49 (21%), and annuloplasty band in 158 (67%). Bidirectional cavopulmonary shunt was performed in 46 patients (20%). There was 1 early death (0.4%). Early reoperation was required in 14 patients (5.9%); re-repair was possible in 7 (50%). The majority of early reoperations (11 of 14; 79%) occurred in the first third of the series. Mean follow-up was 3.5 ± 2.5 years. There was sustained reduction in tricuspid regurgitation (p < 0.0001), a progressive decline in right ventricle size (p < 0.0001), and late increase in right ventricle fractional area change after initial decline (p < 0.0001). Freedom from late reoperation was 97.9% at 6 years.

CONCLUSIONS

Cone repair is safe, and the learning curve is significant. Sustained reduction in tricuspid regurgitation and favorable changes in the right ventricle at follow-up suggest that cone repair has an advantageous impact on right ventricular remodeling.

Ebstein Anomaly

Ebstein anomaly is a rare form of congenital heart disease with a uniquely high prevalence of arrhythmias. The most prevalent arrhythmia mechanisms are intrinsic to the underlying embryologic defects and may manifest at any stage. Current electrophysiological and surgical strategies are well equipped to address these arrhythmia mechanisms, yet despite available technology and a robust understanding of the mechanisms, these cases remain challenging. Surgical techniques that render arrhythmia substrates unreachable mandate comprehensive presurgical electrophysiological assessment and potential ablation. As the population ages, the need to address atrial fibrillation management and risk stratification for sudden cardiac death becomes ever more pertinent.

Arrhythmia Surgery for Adults with Congenital Heart Disease

Patients with repaired or unrepaired congenital heart anomalies are at increased risk for arrhythmia development throughout their lives, often paralleling the need for reoperations for hemodynamic residua. The ability to incorporate arrhythmia surgery into reoperations can result in improvement in functional class and decreased need for antiarrhythmic medications. Every reoperation for congenital heart disease can be viewed as an opportunity to assess the electrical and arrhythmia substrates and to intervene to improve the arrhythmias and the hemodynamic condition of the patient. The authors review and summarize the operative techniques for arrhythmia surgery that are based on the arrhythmia mechanisms.

Prophylactic arrhythmia surgery in association with congenital heart disease

Certain congenital heart anomalies make patients more susceptible to arrhythmia development throughout their lives. This poses the question whether prophylactic arrhythmia surgery should be incorporated into reparative open heart procedures for congenital heart disease. There is currently no consensus on what constitutes a standard prophylactic procedure, owing to the questions that remain regarding lesions to be performed; energy sources to use; proximity of energy source or incisions to coronary arteries, sinoatrial node, atrioventricular node; circumstances for right atrial, left atrial, or biatrial appendectomy; and whether to perform a right, left, or biatrial maze procedure. These considerations are important because prophylactic arrhythmia procedures are performed without knowing if the patient will actually develop an arrhythmia in his or her lifetime. By reviewing and summarizing the literature, congenital heart disease patients who are at risk for developing atrial arrhythmias can be identified and lesion sets can be suggested in an effort to standardize experimental protocols for prophylactic arrhythmia surgery.

Prediction of atrial fibrillation development and progression: Current perspectives

Atrial fibrillation (AF) is the most common arrhythmia in clinical practice. Several conventional and novel predictors of AF development and progression (from paroxysmal to persistent and permanent types) have been reported. The most important predictor of AF progression is possibly the arrhythmia itself. The electrical, mechanical and structural remodeling determines the perpetuation of AF and the progression from paroxysmal to persistent and permanent forms. Common clinical scores such as the hypertension, age ≥ 75 years, transient ischemic attack or stroke, chronic obstructive pulmonary disease, and heart failure and the congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65-74 years, sex category scores as well as biomarkers related to inflammation may also add important information on this topic. There is now increasing evidence that even in patients with so-called lone or idiopathic AF, the arrhythmia is the manifestation of a structural atrial disease which has recently been defined and described as fibrotic atrial cardiomyopathy. Fibrosis results from a broad range of factors related to AF inducing pathologies such as cell stretch, neurohumoral activation, and oxidative stress. The extent of fibrosis as detected either by late gadolinium enhancement-magnetic resonance imaging or electroanatomic voltage mapping may guide the therapeutic approach based on the arrhythmia substrate. The knowledge of these risk factors may not only delay arrhythmia progression, but also reduce the arrhythmia burden in patients with first detected AF. The present review highlights on the conventional and novel risk factors of development and progression of AF.

Ebstein anomaly review: what's now, what's next?

Ebstein anomaly accounts for 1% of all congenital heart disease. It is a right ventricular myopathy with failure of tricuspid valve delamination and highly variable tricuspid valve morphology that usually results in severe regurgitation. It is the only congenital heart lesion that has a range of clinical presentations, from the severely symptomatic neonate to an asymptomatic adult. Neonatal operation has high operative mortality, whereas operation performed beyond infancy and into adulthood has low operative mortality. Late survival and quality of life for hospital survivors are excellent for the majority of patients in all age brackets. Atrial tachyarrhythmias are the most common late complication. There have been more techniques of tricuspid repair reported in the literature than any other congenital or acquired cardiac lesion. This is largely due to the infinite anatomic variability encountered with this anomaly. The cone reconstruction of Ebstein anomaly can achieve near anatomic restoration of the tricuspid valve anatomy. Early and intermediate results with these repairs are promising. Reduced right ventricular function continues to be a challenge for some patients, as is the need for reoperation for recurrent tricuspid regurgitation. The purpose of this article is to outline the current standard of care for diagnosis and treatment of Ebstein anomaly and describe innovative strategies to address poor right ventricular function and associated right-sided heart failure.