Case Report: Remote magnetic navigation and accessory pathways ablation in a single ventricle young adult with complex corrective surgeries

Abstract

Supraventricular arrhythmias have become an increasingly significant contributor to the risk of mortality and morbidity in adults with complex congenital heart disease (CHD), especially in light of recent advances in palliative corrective surgeries. Because of their unique characteristics, they demand specific treatment approaches. While pharmaco-logical interventions are an option, they have limited effectiveness and may lead to side effects. Although performing radiofrequency ablation (RFA) can be exceptionally challenging in patients with complex CHD, due to particular vascular access and also modified anatomy, it has paved the way to enhance comprehension of the underlying mechanisms of supraventricular arrhythmias. This, in turn, enables the provision of improved therapies and, ultimately, an enhancement in the quality of life and symptom management for these patients. The purpose of this case report is to highlight the benefits of utilizing advanced technologies such as three-dimensional electro-anatomical mapping systems, remote magnetic navigation, and highly flexible mapping and ablation catheters during RFA in a young adult with complex congenital heart disease. Although he lacked venous connections to the right atrium (RA) due to multiple corrective surgeries we, remarkably, were capable to advance a decapolar deflectable diagnostic catheter inside the Fontan tunnel and from there to record and stimulate the RA. Successful ablation of two accessory pathways was achieved with no arrhythmia recurrence during follow-up.

Keywords: accessory pathways; atrioventricular reentrant tachycardia; case report; congenital heart disease; electroanatomic mapping; remote magnetic navigation; surgical correction procedures.

Figure 1

Timeline of the patient's medical history with corrective surgeries (Kawashima procedure, lateral Fontan procedure, cardiac catheterisation) and current symptoms. At admission baseline ECG and TTE were performed. Baseline electrocardiogram: sinus rhythm with slightly wide QRS complex suggestive of non-specific intraventricular conduction delay, left anterior fascicular block and diffuse negative T waves. Transthoracic echocardiography: one ventricle with conserved systolic function, 50%–55% visually estimated; minimal regurgitation of the atrioventricular valve. Apparently only one atrium (the interatrial septum was not visualized); inside of it was present the venous conduct with laminarly flux. It was also viewed the rudiment of the right ventricle. The aorta had complete dextroposition and was slightly more anterior than the pulmonary artery. The aortic valve was tricuspid, with no significant regurgitation. At the left of the aorta, it was also visible the pulmonary artery with a hypoplastic pulmonary valve.

Figure 2

(A) ECG during arrhythmia: regular tachycardia, cycle length (CL) of 340 msec, 1:1 ventriculoatrial conduction, RP interval longer than 90 msec, negative P waves in inferior leads, narrow QRS complex without pseudo–R in V1 and pseudo–S in DII–DIII. (B) Intraprocedural recording during radiofrequency applications (56 C, 50 W) with arrythmia termination within seconds. (C) ECG during second arrhythmia: regular tachycardia, CL of 400 msec, 1:1 ventriculoatrial conduction, long RP interval, positive P waves in inferior leads, narrow QRS complex. (D) Intraprocedural recording during radiofrequency applications (56 C, 50 W) with arrythmia termination within seconds.

Figure 3

(A) Fluoroscopic imagine showing the position of the decapolar deflectable catheter into the intra-atrial conduct, with no puncture of the dacron conduit and the position of the thermocool RMT catheter (B,C) electroanatomical CARTO 3 map showing the position of the two accessory pathways in relation to the His bundle (yellow dot). (D) Electroanatomical reconstruction using computed tomography. (E) Intraprocedural electrogram of the His bundle.