Pulmonary vein and cavotricuspid isthmus ablation in situs inversus totalis.

Pulmonary vein isolation (PVI) with cavotricuspid isthmus (CTI) ablation is feasible in patients with situs inversus totalis. Orientation challenges are improved with the use of electroanatomical mapping prior to transseptal puncture. Care must be taken to note the opposing anatomic locations of important structures such as the left atrial appendage, descending aorta, and phrenic nerve.

Introduction

Complex cardiac anatomy in the presence of congenital anomalies of the heart may be challenging to electrophysiologists during catheter ablation procedures. Situs inversus totalis (SIT) is a rare condition in which the major visceral organs are reversed or mirrored from their normal positions, that is the apex of the heart points to the right (dextrocardia). SIT affects approximately 0.01% of the population. Given the anatomic reversal in SIT patients, the use of three‐dimensional electroanatomical mapping is an important tool in aiding in the success of electrophysiology procedures in these patients.

Case Report

A 63‐year‐old male with a history of SIT, status after orthotopic liver and kidney transplant for alcoholic liver cirrhosis and hepatorenal syndrome developed symptomatic persistent atrial fibrillation 2 years following the transplant. He underwent cardioversion, but later developed atrial flutter with rapid ventricular rates despite amiodarone. After reviewing the risks and benefits of the procedure, the patient elected to undergo atrial fibrillation and atrial flutter ablation. Given the reversed anatomy, vascular access was obtained in the left femoral vein for the transseptal puncture. A SOUNDSTAR® (Biosense Webster, South Diamond Bar, CA) catheter was placed into the right atrium (RA) via the right femoral vein. Initially, electroanatomical mapping (EAM) of the RA using CARTO (Biosense Webster, South Diamond Bar, CA) Fast Anatomical Mapping (FAM) was performed (Fig. 1). Utilizing CARTOMERGE and CARTOSOUND Biosense Webster, South Diamond Bar, CA, a map was created to outline extracardiac and left atrium (LA) structures. The pulmonary veins were identified and the LA appendage was anterior to the anatomic right superior pulmonary vein (PV) and the descending aorta was posterior to the anatomic right inferior PV compressing the vein ostium (Fig. 2). An anatomical left to right transseptal puncture was performed under intracardiac ultrasound (Fig. 3) and fluoroscopic guidance (Fig. 4). Further EAM of the LA was performed to supplement the CARTOSOUND map. Radiofrequency pulmonary vein isolation (PVI) was then performed, using a 3.5 mm Thermocool F (Biosense Webster, South Diamond Bar, CA), ablation catheter taking care to note the location of the phrenic nerve (black dots) during ablation adjacent to the left PVs (Fig. 5). Entrance block was confirmed with the elimination of PV potentials on the CARTO Lasso (Biosense Webster, South Diamond Bar, CA) Variable Catheter placed within the ostia of each PV. Exit block was demonstrated during pacing (via CARTO Lasso Variable Catheter) from within all four PVs. Adenosine 12 mg was also administered with the catheter in each of the veins without transient reconnection. Next, all catheters were withdrawn from the left atrium and a cavotricuspid isthmus (CTI) ablation was performed utilizing the previously created RA FAM. Bidirectional block was achieved. The patient has since remained arrhythmia free, off antiarrhythmic medications, at 1 year after procedure follow‐up.

Figure 1

Electroanatomical map of the right and left atria utilizing CARTO FAM and CARTOSOUND . CS: coronary sinus, CTI: cavotricuspid isthmus, LA: left atrium, LAA: Left atrial appendage, RIPV: anatomic right inferior pulmonary vein, RSPV: anatomic right superior pulmonary vein, SVC: superior vena cava.

Figure 2

A map outlining the relationship between extracardiac and LA structures created by CARTOMERGE and CARTOSOUND systems. AO: Aorta, LA: left atrium, LAA: Left atrial appendage, LIPV: anatomic left inferior pulmonary vein, LSPV: anatomic left superior pulmonary vein, MPA: main pulmonary artery.

Figure 3

Intracardiac echocardiography view during transseptal puncture; the anatomical right superior pulmonary vein, functionally the left superior pulmonary vein, is seen in this view. FO: Fossa ovalis, LA: left atrium, RSPV: anatomic right superior pulmonary vein.

Figure 4

A: Fluoroscopic anteroposterior view during transseptal puncture for pulmonary vein isolation with a wire in the anatomical right superior pulmonary vein, functionally the left upper pulmonary vein; note the direction of the transseptal sheath from left to right into the functional left atrium. Also, note the right location of the coronary sinus catheter posterior to the functional mitral valve. B: Fluoroscopic right anterior oblique view during cavotricuspid isthmus isolation; note the left location of the cavotricuspid isthmus, and –hence‐ the functional tricuspid valve AC: ablation catheter, CSC: coronary sinus catheter, TSS: transseptal sheath.

Figure 5

Postero‐anterior view of the left atrium showing ablation lesion set around the pulmonary veins. Phrenic nerve is marked with the black dots. LA: left atrium, LAA, LIPV: anatomic left inferior pulmonary vein, LSPV: anatomic left superior pulmonary vein, PN: Phrenic nerve, RIPV: anatomic right inferior pulmonary vein, RSPV: anatomic right superior pulmonary vein.

Discussion

As previously reported 1, 2, 3, 4, 5, PVI with CTI ablation is feasible in patients with dextrocardia. Orientation challenges are improved with the use of EAM and intracardiac ultrasound. Care must be taken to note the opposing anatomic locations of important structures such as the left atrial appendage, descending aorta and phrenic nerve.

Conflict of Interest

None declared.