Ebstein's Anomaly: Review of Arrhythmia Types and Morphogenesis of the Anomaly

Electrophysiologic Considerations in Adult Patients with Ebstein's Anomaly

Ebstein's anomaly (EA) is a rare cyanotic form of congenital heart disease (CHD) characterized by apical displacement of the tricuspid valve, with resultant hemodynamic and electrical manifestations. The severity of symptoms is determined by the degree of apical displacement and deformity and incompetence of the tricuspid valve. As a result, patients with EA can be severely symptomatic during infancy and childhood or can be incidentally discovered in the sixth or seventh decade of life. Hallmarks of Ebstein's anomaly include progressive cyanosis, right-sided heart failure, and tachyarrhythmias, among which tachyarrhythmias (most commonly atrial, but also ventricular) are the most common presenting symptoms in Ebstein's anomaly patients during adulthood. This review aims to provide insight into the genetic and electrophysiological (EP) basis underlying the tachyarrhythmias encountered when managing patients with EA.

Adults with congenital heart disease: what every cardiologist should know about their care

As patients with congenital heart disease (CHD) continue to enjoy longer lives, non-congenital cardiologists and other healthcare professionals are increasingly encountering them in their practice and are challenged by their specific needs. Most under- and post-graduate medical training tends to overlook this common pathology, resulting in insufficient awareness of post-repair or post-palliation residual lesions and sequelae from previous interventions. In a strive towards improving the quality of care for this ever-growing cardiovascular patient cohort, it is prudent to outline the areas of concern and specific management needs pertaining to adult patients with CHD and share it with non-CHD professionals. The purpose of this paper is to offer essential guidance to physicians, including cardiologists, when they encounter a patient with CHD in a non-congenital healthcare setting.

Pharmacological resynchronisation with flecainide in an infant with Ebstein anomaly and Wolff-Parkinson-White pattern: a case report

Background

Conduction abnormalities are frequently encountered in patients with Ebstein anomaly. The following case describes the safe use of flecainide in an infant with accessory-pathway mediated left ventricular dysfunction in the setting of Ebstein anomaly.

Case Summary

An infant with an antenatal diagnosis of Ebstein anomaly developed progressive left ventricular dilatation and dysfunction over the first 2 months of life. ECG demonstrated persistent Wolff-Parkinson-White pattern with delta-wave polarity suggesting a right-sided septal accessory pathway. In the absence of SVT, accessory-pathway mediated dyssynchrony was suspected as the cause for left ventricular dilatation and dysfunction. He was commenced on flecainide which successfully blocked antegrade conduction via the accessory pathway resulting in a reduction in left ventricular volume and improvement in left ventricular systolic function. He remains asymptomatic at 12 months of age.

Discussion

There is a known association between Ebstein anomaly and Wolff-Parkinson-White pattern. Right-sided septal accessory pathways can cause cardiomyopathy secondary to dyssynchronous left ventricular contraction. In patients who are unsuitable for accessory pathway ablation, flecainide can be used to block antegrade conduction via the accessory pathway resulting in improved left ventricular function, which was successful on this occasion.

Distal His bundle pacing in a patient with surgically corrected complex Ebstein anomaly and symptomatic second-degree atrioventricular block: a case report

Background

Ebstein's anomaly occurs when there is an apical displacement of the tricuspid valve with septal and posterior valve leaflets tethering. This condition often occurs in association with other congenital, structural, or conduction system diseases, including intracardiac shunts, valvular lesions, arrhythmias, accessory conduction pathways, and first-degree atrioventricular (AV) block. We present for the first time a case of a patient with Ebstein's anomaly who presented with second-degree Mobitz II AV block and was successfully treated with conduction system pacing (CSP) due to her young age and the likelihood of a long-term high percentage of pacing.

Case summary

We present a case of a 42-year-old lady with a background of complex congenital heart disease, including severe pulmonary stenosis, Ebstein anomaly, and atrial septal defect (ASD). She required complex surgical intervention, including tricuspid valve (TV) repair and subsequently replacement, ASD closure, and pulmonary balloon valvuloplasty. She presented to our hospital with symptomatic second-degree Mobitz II AV block (dizziness, shortness of breath, and exercise intolerance) and right bundle branch block (RBBB) on her baseline ECG. Her echocardiogram showed dilated right ventricle (RV) and left ventricle (LV) with low normal LV systolic function. Due to her young age and the likelihood of a long-term high percentage of RV pacing, we opted for CSP after a detailed discussion and patient consent. The distal HIS position is the preferred pacing strategy at our centre. We could not cross the TV with the standard Medtronic C315 HIS catheter, so we had to use the deflectable C304 HIS catheter. Mapping and pacing of the distal HIS bundle were achieved by Medtronic Selectsecure 3830, 69 cm lead. HIS bundle pacing led to the correction of both second-degree Mobitz II AV block and pre-existing RBBB. The implantation was uneventful, and the patient was discharged home the next day without any acute complications.

Discussion

Distal HIS pacing is feasible in patients with surgically treated complex Ebstein anomaly and heart block. This approach can normalize the QRS complex with a high probability of preserving or improving LV function.

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.

Successful Radiofrequency Ablation of the Right Lateral Accessory Pathway with Modified Carpentier Reconstruction Surgery in a Patient with Ebstein Anomaly Concomitant of Secundum Atrial Septal Defect, Atrial Fibrillation, and Wolff–Parkinson–White Syndrome

Ebstein anomaly (EA) results from the failure of proper delamination of the tricuspid valve leaflets from the right ventricle (RV) myocardium. The severity of EA occurs on a spectrum that results in varying degrees of tricuspid regurgitation, atrial dilation, RV dilation, and dysfunction. These effects have the potential to create substrates that can give rise to atrial arrhythmia, ventricular arrhythmia, and a greater incidence of Wolff–Parkinson–White (WPW) syndrome Wackel et al. (2018) accounting for 0.5% of all congenital heart diseases (Oh et al. 1985). In the case of atrial fibrillation and WPW, it is very dangerous for the patient because of hemodynamic compromise, syncope, and sudden death. In this case report, we share our experience in using radiofrequency ablation to ablate right lateral accessory pathway, with modified Carpentier technique in operation to treat an adult patient diagnosed with Ebstein anomaly, atrial septal defect, atrial fibrillation, and WPW syndrome.