Efficacy of High-Density Three-Dimensional Mapping for Verapamil-Sensitive Left Posterior Fascicular Ventricular Tachycardia in Pediatric Patients.

In verapamil-sensitive left posterior fascicular ventricular tachycardia (LPF-VT), radiofrequency catheter ablation (RFA) is performed targeting mid-to-late diastolic potential (P1) and presystolic potential (P2) during tachycardia. This study included four patients who had undergone electrophysiological study (EPS) and pediatric patients with verapamil-sensitive LPF-VT who had undergone RFA using high-density three-dimensional (3D) mapping. The included patients were 11-14 years old. During EPS, right bundle branch block and superior configuration VT were induced in all patients. VT mapping was performed via the transseptal approach. P1 and P2 during VT were recorded in three of the four patients. All patients initially underwent RFA via the transseptal approach. In three patients, P1 during VT was targeted, and VT was terminated. The lesion size indices in which VT was terminated were 4.6, 4.6, and 4.7. For one patient whose P1 could not be recorded, linear ablation was performed perpendicularly in the area where P2 was recorded during VT. Among the three patients in whom VT was terminated, linear ablation was performed in two to eliminate the ventricular echo beats. In all patients, VT became uninducible in the acute phase and had not recurred 8-24 months after RFA. High-density 3D mapping with an HD Grid Mapping Catheter allows recording of P1 and P2 during VT and may improve the success rate of RFA in pediatric patients with verapamil-sensitive LPF-VT.

Ultra-high-density three-dimensional mapping system and radiofrequency catheter ablation for intra-atrial reentrant tachycardia in a patient with atriopulmonary connection Fontan.

A 33-year-old man, who had undergone atriopulmonary connection Fontan procedure (AP Fontan) for double outlet right ventricle, suffered from heart failure due to atrial tachycardia at 27 years old. Atrial tachycardia was suppressed after amiodarone administration. At 32 years old, atrial tachycardia recurred, and short palpitations gradually increased. Cardiac computed tomography showed that coronary sinus (CS) was perfused into the pulmonary venous atrium, and catheter insertion to CS from the systemic venous atrium was impossible. We performed an electrophysiology study (EPS) and radiofrequency catheter ablation (RFCA) under local anesthesia. An esophageal electrode catheter was inserted as a potential reference for ultra-high density three-dimensional (3D) mapping system. Two types of atrial tachycardia were induced by EPS. Ultra-high-density 3D mapping system revealed an intra-atrial reentrant pattern around the scar area on the lower right atrium in both atrial tachycardias; therefore, we diagnosed intra-atrial reentrant tachycardia (IART). The low voltage area and inferior vena cava during IART were ablated linearly, and IART was terminated.In conclusion, a CS electrode catheter cannot be inserted in a patient with AP Fontan, and ultra-high-density 3D mapping using the esophageal electrode catheter as a potential reference enables accurate and rapid mapping and is very effective for RFCA. Learning objective: The incidence of intra-atrial reentrant tachycardia (IART) is high in patients with late after Fontan procedure, and the treatment may be difficult. Ultra-high-density three-dimensional mapping can perform accurate mapping of IART and rapid detection of low voltage areas effective for radiofrequency catheter ablation. An esophageal electrode catheter can be the reference potential for accurate activation mapping in Fontan patients where coronary sinus electrode catheter insertion may be impossible from a systemic venous atrium.

The efficacy of pacemaker implantation for extracardiac total cavopulmonary connection in a pediatric patient with bradycardia-tachycardia syndrome.

A 9-year-old boy, diagnosed with double outlet right ventricle after birth, suffered sinus node dysfunction and non-sustained junctional tachycardia after an extracardiac total cavopulmonary connection (TCPC). Spontaneous atrial tachycardia appeared 3 years after an extracardiac TCPC. Sotalol was administered but the bradycardia was obvious. It was difficult to increase sotalol and atrial tachycardia was uncontrollable. Atrial tachycardia continued with symptoms; direct current (DC) cardioversion was frequently required. Five years after extracardiac TCPC, we implanted a pacemaker with atrial antitachycardia pacing (ATP) using epicardial leads. On day 2 post operation, wide QRS tachycardia appeared. Due to decreased blood pressure, DC cardioversion was immediately performed, but it recurred from atrial premature contraction. We judged this was atrial tachycardia with 1:1 atrioventricular conduction based on an intracardiac electrogram and it was terminated by burst atrial pacing from the pacemaker. After changing atrial pacing rate to 150 ppm, atrial tachycardia could be suppressed. Due to atrial pacing and increasing sotalol gradually, junctional tachycardia terminated spontaneously, and atrial tachycardia was not induced after pacemaker implantation. In conclusion, implantation of a pacemaker with ATP and intensification of antiarrhythmic drugs is an effective treatment strategy for pediatric patients with bradycardia-tachycardia syndrome after extracardiac TCPC. .