Arrhythmias Following the Mustard and Senning Operations for Dextro-Transposition of the Great Arteries: Clinical Aspects and Catheter Ablation

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.

Atrial Arrhythmia Ablation in Patients With D-Transposition of the Great Arteries and Atrial Switch

BACKGROUND

Patients with D-transposition of the great arteries and atrial switch have a high incidence of atrial arrhythmias. We sought to analyze the arrhythmia substrate, ablation strategies, and outcomes for catheter ablation in this population.

METHODS

An in-depth analysis of all clinical and procedural data in patients with D-transposition of the great arteries, atrial baffles, and atrial arrhythmia ablation was performed.

RESULTS

A cohort of 32 patients (72% male, mean age 38±7 years) underwent ablation for non-AV nodal reentrant tachycardia atrial arrhythmias, and 4 patients underwent AV nodal reentrant tachycardia ablation. Cavotricuspid isthmus flutter (CTI-flutter) was the most common arrhythmia, encountered in 75% of patients, followed by scar-related intraatrial reentrant tachycardia (non-CTI intraatrial reentrant tachycardia, 53%) and focal atrial tachycardia (focal atrial tachycardia, 6%). Among the 32 patients, 26 underwent 31 procedures at our institution. For patients with prior outside intervention, the index ablation at our institution revealed CTI-dependent flutter in 3/5 cases. However, redo ablation after an index ablation with demonstrated bidirectional CTI block revealed different/new arrhythmia substrates (80% non-CTI intraatrial reentrant tachycardia, 40% focal atrial tachycardia). Achieving bidirectional block across the CTI often required ablating on both sides of the baffle (retroaortic access, 81%; using a baffle leak, 11.5%; or transbaffle puncture, 7.7%). Combined approaches were necessary in 19% to reach the critical tissue. Acute procedural success was 81%, and recurrence was documented in 58% of patients. Despite recurrence, clinical arrhythmia burden was significantly reduced post-ablation (P<0.001), with rare episodes, amenable to antiarrhythmic therapy. Redo ablation was required in 5 (19%) patients and uncovered new arrhythmia substrates. AV nodal reentrant tachycardia ablation also required transbaffle approaches in 3/4 patients.

CONCLUSIONS

CTI-dependent flutter was the most common arrhythmia in patients with Dextro-Transposition of the Great Arteries and atrial switch. Transbaffle approaches were often necessary, and, provided that bidirectional CTI block was achieved at the index ablation, late recurrence was due to different arrhythmia mechanisms. Despite recurrence, ablation was associated with significant clinical improvement.

Therapy of supraventricular and ventricular arrhythmias in adults with congenital heart disease-narrative review

Arrhythmias are among the most common late complications in adults with congenital heart disease (ACHD) and a frequent reason for hospital admission. Both, supraventricular and ventricular arrhythmias, not only cause debilitating symptoms, but may be life-threatening by increasing risk of stroke, causing or worsening heart failure and being associated with sudden death. Substrate and risk for arrhythmia differs widely between congenital defects with specific arrhythmias being much more common in some patients than others. Atrial macroreentrant arrhythmias are particularly frequent in patients with atrial septal defects and repair that involves atrial incisions including patients with transposition of the great arteries (TGA) and atrial switch. Accessory pathways and related arrhythmias are often associated with Ebstein's anomaly and congenitally corrected TGA. Monomorphic ventricular arrhythmias occur in patients with ventricular incisions, namely patients with Tetralogy of Fallot. Changes in surgical repair techniques influence arrhythmia prevalence and substrate as well as anatomical access for catheter ablation procedures. In addition, epidemiologic changes associated with improved long-term survival will further increase the prevalence of atrial fibrillation in ACHD. This article summarizes current understanding of prevalence of specific arrhythmias, underlying mechanisms, medical and interventional treatment options and their outcome in ACHD.

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.