EP challenges in adult congenital heart disease

Arrhythmias in Adult Congenital Heart Disease Heart Failure

Heart failure and arrhythmias represent 2 major causes of mortality and morbidity in adults with congenital heart disease. Arrhythmias and heart failure are interdependent, and one may exacerbate the other. Treatment of one also has a positive impact on the other. Management approaches need to be multifaceted, including pharmacotherapy, optimization of hemodynamic status with catheter-based or surgical interventions, and specific management of arrhythmia with device or catheter ablation therapy.

Cardiac resynchronization therapy using conduction system pacing after double-switch surgery for congenitally corrected transposition of the great arteries: a case report

Background

Patients with congenitally corrected transposition of the great arteries (ccTGA) are at risk of developing conduction disease and complete atrio-ventricular block and this risk increases after corrective cardiac surgery. However, the optimum pacing modality remains controversial.

Case summary

Twelve years after a double-switch surgery with ventricular septal defect correction, a 16-year-old ccTGA female was referred with an indication for cardiac resynchronization therapy. In the absence of coronary sinus (CS) or direct access to the conduction system, several therapeutic options were considered. Finally, using a three-dimensional navigation system and customized sheaths, a left bundle branch area pacing (LBBAP) lead was successfully implanted. The implantation resulted in stable pacing parameters and positive haemodynamic changes. At 9-month follow-up, pacing parameters were stable and the patient reported a significant improvement in quality of life.

Discussion

Cardiac resynchronization therapy in adults with repaired congenital heart disease remains challenging, especially in the absence of CS or direct access to the conduction system. In such a situation, LBBAP appears as an attractive alternative pacing modality. However, pre-operative management is critical to the success of the implantation.

Safety of transvenous lead removal in adult congenital heart disease: a national perspective

INTRODUCTION AND OBJECTIVES

Data are scarce on outcomes of transvenous lead removal (TLR) in adult congenital heart disease (CHD). We evaluated the safety of the TLR procedure in adult CHD patients from a 10-year national database.

METHODS

We used the Healthcare Cost and Utilization Project Nationwide Inpatient Sample to identify TLR procedures in adult patients with and without CHD from 2005 to 2014. Outcomes included in-hospital mortality and complications.

RESULTS

Of 132 068 adult patients undergoing TLR, 1939 had simple CHD, 657 had complex CHD, and 626 had unclassified CHD. The number of TLR procedures in adult CHD slightly increased from 236 in 2005 to 445 in 2014, with fluctuations over the study period. The overall rate of any complications in the TLR procedure was 16.6% in patients with CHD vs 10.1% in patients without CHD (P <.001). In a propensity score-matched cohort, CHD was associated with a higher risk of any complication after full adjustment vs patients without CHD (adjusted odd ratio, 1.49; 95% confidence interval, 1.11-1.99; P=.007). Simple and complex CHD were associated with 1.5- and 2.1-fold increased risks of any TLR-related complication, respectively. CHD was not associated with an increased risk of in-hospital mortality (adjusted odd ratio, 0.77; 95% confidence interval, 0.42-1.39; P=.386).

CONCLUSIONS

Compared with patients without CHD, adult patients with simple and complex CHD undergoing TLR are more likely to have complications but show no increase in mortality.

Morphological Substrates for Atrial Arrhythmogenesis in a Heart With Atrioventricular Septal Defect

Due to advances in corrective surgery, congenital heart disease has an ever growing patient population. Atrial arrhythmias are frequently observed pre- and post-surgical correction. Pharmaceutical antiarrhythmic therapy is not always effective, therefore many symptomatic patients undergo catheter ablation therapy. In patients with atrioventricular septal defects (AVSD), ablation therapy itself has mixed success; arrhythmogenic recurrences are common, and because of the anatomical displacement of the atrioventricular node, 3-degree heart block post-ablation is a real concern. In order to develop optimal and safe ablation strategies, the field of congenital cardiac electrophysiology must combine knowledge from clinical electrophysiology with a thorough understanding of the anatomical substrates for arrhythmias. Using image-based analysis and multi-cellular mathematical modeling of electrical activation, we show how the anatomical alterations characteristic of an AVSD serve as arrhythmogenic substrates. Using ex-vivo contrast enhanced micro-computed tomography we imaged post-mortem the heart of a 5 month old male with AVSD at an isometric spatial resolution of 38 μm. Morphological analysis revealed the 3D disposition of the cardiac conduction system for the first time in an intact heart with this human congenital malformation. We observed displacement of the compact atrioventricular node inferiorly to the ostium of the coronary sinus. Myocyte orientation analysis revealed that the normal arrangement of the major atrial muscle bundles was preserved but was modified in the septal region. Models of electrical activation suggest the disposition of the myocytes within the atrial muscle bundles associated with the "fast pathway," together with the displaced atrioventricular node, serve as potential substrates for re-entry and possibly atrial fibrillation. This study used archived human hearts, showing them to be a valuable resource for the mathematical modeling community, and opening new possibilities for the investigations of arrhythmogenesis and ablation strategies in the congenitally malformed heart.

Cardiac resynchronization therapy in congenital heart disease

Cardiac resynchronization therapy (CRT) is an established treatment option for adult patients suffering heart failure due to idiopathic or ischemic cardiomyopathy associated with electromechanical dyssynchrony. There is limited evidence suggesting similar efficacy of CRT in patients with congenital heart disease (CHD). Due to the heterogeneity of structural and functional substrates, CRT implantation techniques are different with a thoracotomy or hybrid approach prevailing. Efficacy of CRT in CHD seems to depend on the anatomy of the systemic ventricle with best results achieved in systemic left ventricular patients upgraded to CRT from conventional pacing. Indications for CRT in patients with CHD were recently summarized in the Pediatric and Congenital Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS) Expert Consensus Statement on the Recognition and Management of Arrhythmias in Adult Congenital Heart Disease and are presented in the text.

Primary Prevention of Sudden Cardiac Death in Adults with Transposition of the Great Arteries: A Review of Implantable Cardioverter-Defibrillator Placement

Transposition of the great arteries encompasses a set of structural congenital cardiac lesions that has in common ventriculoarterial discordance. Primarily because of advances in medical and surgical care, an increasing number of children born with this anomaly are surviving into adulthood. Depending upon the subtype of lesion or the particular corrective surgery that the patient might have undergone, this group of adult congenital heart disease patients constitutes a relatively new population with unique medical sequelae. Among the more common and difficult to manage are cardiac arrhythmias and other sequelae that can lead to sudden cardiac death. To date, the question of whether implantable cardioverter-defibrillators should be placed in this cohort as a preventive measure to abort sudden death has largely gone unanswered. Therefore, we review the available literature surrounding this issue.

Dual-Chamber Stimulation with Single-Lead VDD Pacing System in Mustard Surgery

Sinus node disease is a problem encountered in patients after the Mustard surgery, requiring a pacemaker implantation. The knowledge of the complexity anatomy is crucial because of the possible challenges associated with this procedure. We report a case of a 24-year-old woman presented with symptomatic bradycardia, in which a bicameral stimulation using a single-lead VDD pacing system was successfully performed.

Tachyarrhythmias and catheter ablation in adult congenital heart disease

Advances in surgical technique have had an immense impact on longevity and quality of life in patients with congenital heart disease. However, an inevitable consequence of these surgical successes is the creation of a unique patient population whose anatomy, surgical history and haemodynamics result in the development of a challenging and complex arrhythmia substrate. Furthermore, this patient group remains susceptible to the arrhythmias seen in the general adult population. It is through a thorough appreciation of the cardiac structural defect, the surgical corrective approach, and haemodynamic impact that the most effective arrhythmia care can be delivered. Catheter ablation techniques offer a highly effective management option but require a meticulous attention to the real-time integration of anatomical and electrophysiological information to identify and eliminate the culprit arrhythmia substrate. This review describes the current approach to the interventional management of patients with tachyarrhythmias in the context of congenital heart disease.

Life-threatening atrial tachycardia after the Senning operation in a patient with transposition of the great arteries

Atrial tachycardia (AT) is recognized as a risk factor of sudden death (SD) in patients with transposition of the great arteries (TGA) after atrial switch operation. A 20-year-old man with TGA who had undergone a Senning operation experienced a near-miss SD event 1 day after appearance of AT. He was successfully resuscitated by electrical defibrillation for documented ventricular fibrillation. An electrophysiological study showed three types of AT, and all of them were terminated by radiofrequency catheter ablation (RFCA). We consider that symptomatic AT against cardiac medications is indicated for RFCA therapy.

Recent advances in adult congenital heart disease

As a result of major achievements in pediatric cardiac care, a growing number of patients with congenital heart disease (CHD) are flourishing well into adulthood. This heterogeneous and aging population of patients, many of whom represent the first generation of middle-age survivors, faces unique issues and challenges. As a field, adult CHD has evolved markedly during the past decade on several fronts, including imaging, arrhythmia management, percutaneous interventions, surgical techniques, research, and multidisciplinary care that extends beyond the cardiac realm. This review highlights recent advances across the wide spectrum of key issues encountered by adults with CHD.

Treatment of congenital heart disease: risk-reducing measures in young adults

Adults with congenital heart disease form a new and relatively young population, since surgical treatment of heart defects became available three to four decades ago. Owing to improved survival this population is steadily growing in number and age. Little is known regarding long-term survival; however, late complications occur frequently. During adulthood, almost half of the patients have one or more complication, such as endocarditis, stroke, systemic or pulmonary hypertension, aortic aneurysm or dissection and arrhythmias. Heart failure and sudden cardiac death are the main causes of death. Treatment of adults with congenital heart disease is aimed at the reduction of symptoms, but also at minimizing the risk and severity of late complications. In this article the most recent advances in the treatment of congenital heart disease will be discussed. The main focus of the article will be on pharmacological, interventional and surgical interventions that reduce the risk of heart failure, arrhythmias, vascular complications, pulmonary hypertension and endocarditis.

Canadian Cardiovascular Society 2009 Consensus Conference on the management of adults with congenital heart disease: complex congenital cardiac lesions

With advances in pediatric cardiology and cardiac surgery, the population of adults with congenital heart disease (CHD) has increased. In the current era, there are more adults with CHD than children. This population has many unique issues and needs. They have distinctive forms of heart failure and their cardiac disease can be associated with pulmonary hypertension, thromboemboli, complex arrhythmias and sudden death. Medical aspects that need to be considered relate to the long-term and multisystemic effects of single ventricle physiology, cyanosis, systemic right ventricles, complex intracardiac baffles and failing subpulmonary right ventricles. Since the 2001 Canadian Cardiovascular Society Consensus Conference report on the management of adults with CHD, there have been significant advances in the field of adult CHD. Therefore, new clinical guidelines have been written by Canadian adult CHD physicians in collaboration with an international panel of experts in the field. Part III of the guidelines includes recommendations for the care of patients with complete transposition of the great arteries, congenitally corrected transposition of the great arteries, Fontan operations and single ventricles, Eisenmenger's syndrome, and cyanotic heart disease. Topics addressed include genetics, clinical outcomes, recommended diagnostic workup, surgical and interventional options, treatment of arrhythmias, assessment of pregnancy risk and follow-up requirements. The complete document consists of four manuscripts, which are published online in the present issue of The Canadian Journal of Cardiology. The complete document and references can also be found at www.ccs.ca or www.cachnet.org.