Interventional Therapy of Supraventricular Tachycardias in Two Patients with Azygos Continuation and Complex Congenital Heart Defects

Objectives: Azygos continuation is a rare congenital anomaly in which the IVC is interrupted below the hepatic vein and venous return beyond this point is restored by the dilated azygos vein draining into the SVC. An association with complex congenital heart defects, especially with left isomerism is common. The prevalence of supraventricular tachycardia (SVT) is high, the interventional therapy is challenging.

Methods: In two patients with azygos continuation and recurrent SVT, an electrophysiology study (EPS) was performed. Diagnostic catheters were positioned via the right femoral vein → IVC → azygos vein → SVC in the right heart (RA/RV) and a reference catheter was introduced into the esophagus. In the first patient, an additional catheter was placed via the jugular vein at the bundle of His. In both patients, a voltage map during sinus rhythm and an activation map during SVT using the NavX system was performed. The first patient was a 13-year-old girl with a history of Senning–Rastelli procedure due to cc-TGA, pulmonary atresia and VSD with criss cross heart. During EPS, a focal atrial tachycardia (FAT) with a focus in the upper baffle, as well as a typical atrial nodal reentrant tachycardia (AVNRT), was induced. Radiofrequency (RF) ablation of the documented and clinically relevant FAT with a termination of the FAT during ablation could be achieved. The second patient was an 11-year-old girl with left isomerism and a history of surgical correction of a total anomalous pulmonary venous connection and sinus venosus malformation. In the further course, she developed a tachycardiomyopathy due to recurrent SVT. Despite antiarrhythmic therapy with sotalol and multiple other therapies in different centers SVT were still noted. EPS revealed an atrial reentrant tachycardia (ART) around areas of scar tissue in the right atrium, as well as a typical AVNRT. We performed RF ablation of the clinically documented ART by inducing an RF line between the areas of scar tissue.

Result: Six and 18 months after EPS, both patient are still free of arrhythmias, respectively. However, the second patient still receives Sotalol due to the history of tachycardiomyopathy.

Conclusion: The interventional therapy of patients with azygos continuation and congenital heart defect is complicated by the difficult way of access site, as well as by the variable anatomy of the conduction system. Nevertheless, a significant improvement of the rhythmological situation can be achieved in most cases.

Publikationsverlauf

Artikel online veröffentlicht:
21. Februar 2021