Catheter ablation for patients with end-stage complex congenital heart disease or cardiomyopathy considered for transplantation: Trials and tribulations

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.

Clinical Impact of Cardiac Fibrosis on Arrhythmia Recurrence after Ablation in Adults with Congenital Heart Disease

BACKGROUND

Adults with congenital heart disease (ACHD) are often affected by cardiac arrhythmias requiring catheter ablation. Catheter ablation in this setting represents the treatment of choice but is flawed by frequent recurrencies. Predictors of arrhythmia relapse have been identified, but the role of cardiac fibrosis in this setting has not been investigated. The aim of this study was to determine the role of the extension of cardiac fibrosis, detected by electroanatomical mapping, in predicting arrhythmia recurrencies after ablation in ACHD.

MATERIALS AND METHODS

Consecutive patients with congenital heart disease and atrial or ventricular arrhythmias undergoing catheter ablation were enrolled. An electroanatomical bipolar voltage map was performed during sinus rhythm in each patient and bipolar scar was assessed according to the current literature data. During follow-up, arrhythmia recurrences were recorded. The relationship between the extent of myocardial fibrosis and arrhythmia recurrence was assessed.

RESULTS

Twenty patients underwent successful catheter ablation of atrial (14) or ventricular (6) arrhythmias, with no inducible arrhythmia at the end of the procedure. During a median follow-up period of 207 weeks (IQR 80 weeks), eight patients (40%; five atrial and three ventricular arrhythmias) had arrhythmia recurrence. Of the five patients undergoing a second ablation, four showed a new reentrant circuit, while one patient had a conduction gap across a previous ablation line. The extension of the bipolar scar area (HR 1.049, CI 1.011-1.089, p = 0.011) and the presence of a bipolar scar area >20 cm² (HR 6.101, CI 1.147-32.442, p = 0.034) were identified as predictors of arrhythmia relapse.

CONCLUSION

The extension of the bipolar scar area and the presence of a bipolar scar area >20 cm² can predict arrhythmia relapse in ACHD undergoing catheter ablation of atrial and ventricular arrhythmias. Recurrent arrhythmias are often caused by circuits other than those previously ablated.

Successful Radiofrequency Ablation of Recurrent Supraventricular Tachycardia in a Patient with Complex Congenital Heart Disease

BACKGROUND Radiofrequency ablation (RFA) is the criterion standard treatment for patients with atrioventricular nodal reentrant tachycardia (AVNRT). Knowledge about RFA in patients with dextrocardia and situs inversus is limited due to their rare incidence and complexity. The incidence of dextrocardia is reported to be 1 in 12 000 births, with situs inversus occurring in one-third of the cases. The incidence of congenital heart disease is about 5% in these patients. However, data on rhythm and conduction disorders in this group of patients are currently limited, making management more difficult owing to their individual anatomy. CASE REPORT We report the case of an obese 21-year-old man with complex congenital heart disease (CCHD) (situs inversus dextrocardia, pulmonary atresia, single ventricle, common atrium with single atrioventricular valve), asplenia, and multiple cardiac-corrective surgeries (Fontan repair, bidirectional Glenn anastomosis, and Blalock-Taussig shunt) who underwent successful RFA of recurrent supraventricular tachycardia. CONCLUSIONS Supraventricular arrhythmias are common in the setting of CCHD. Although catheter ablation procedures are technically challenging to perform in patients with CCHD, they remain the best therapeutic option for these arrhythmias. To our knowledge, this case is the first to be described in the literature of successful ablation of AVNRT in a patient with situs inversus dextrocardia, pulmonary atresia, a single ventricle, a common atrium with a single atrioventricular valve, and multiple cardiac-corrective surgeries.

Imaging of complications following Fontan circulation in children - diagnosis and surveillance

The Fontan operation is performed for various cardiac lesions with single-ventricle physiology. The survival rate of Fontan patients is increasing for adolescents and young adults, with an expected 30-year survival of >80%. Medical health care providers including specialists in organ systems and pediatric radiologists need to improve their knowledge about the Fontan circulation and the various organ complications to monitor care. In this review the author explains the basic anatomical and functional features of Fontan palliation and gives an overview of the multiple long-term organ complications that might present in the pediatric population. These include decreased physical capacity, ventricular dysfunction, atrioventricular valve regurgitation and arrhythmia, as well as protein-losing enteropathy, plastic bronchitis, growth/bone composition disturbances, renal dysfunction, and the recently recognized and important liver fibrosis (Fontan-associated liver disease). Neuropsychological and behavioral deficits occur frequently. This review focuses on the key role of radiology in making the diagnosis of these complications, monitoring therapy and predicting outcomes in the pediatric age group. The author discusses how and when radiology is important in Fontan patients, as well as how new techniques enabling quantitative measures in imaging with US, MRI and CT are adapted for pediatric use, and how they contribute to urgently needed surveillance strategies.