Looking into the mirror: Pulmonary vein isolation in a patient with dextrocardia, complete situs inversus, and interrupted inferior vena cava

Key Teaching Points.

• •Dextrocardia with complete situs inversus and interrupted inferior vena cava with azygos continuation into a persistent left-sided superior vena cava (SVC) provides a unique anatomic challenge for atrial fibrillation (AF) ablation.
• •AF ablation has been performed with this anatomy using an SVC-only approach, but catheter manipulation is challenging, an electroanatomic map could not be created, and ablation of non–pulmonary vein triggers may be limited.
• •Here, we describe use of a transhepatic approach, which facilitated complete electroanatomic mapping of the left atrium, bilateral pulmonary vein isolation, and ablation of AF triggers in the persistent left-sided SVC.

Introduction

Pulmonary vein isolation (PVI), which involves circumferential ablation around the ostia of the pulmonary veins to achieve electrical isolation, is the cornerstone of catheter ablation for atrial fibrillation (AF).¹ PVI is typically achieved via femoral venous access, through which sheaths and catheters are advanced to the right heart, and transseptal puncture is performed to advance catheters to the left atrium (LA), where circumferential ablation can be performed around the pulmonary veins.²

Dextrocardia is a rare congenital anomaly in which the heart develops on the right side of the body, with an incidence of approximately 1 in over 12,000 pregnancies.³ About one-third of patients with dextrocardia also exhibit complete reversal of the usual visceroatrial organ configuration, which is termed complete situs inversus (CSI).³ CSI is most frequently isolated, but can be associated with other cardiac and noncardiac congenital anomalies.

Small series have described AF ablation in the setting of CSI, but generally using standard venous access approaches.⁴ CSI with an interrupted inferior vena cava (IVC) with azygos vein continuation into a persistent left-sided superior vena cava (SVC) is a unique anatomical challenge that may impact the feasibility of PVI. A single case of AF ablation has been reported with similar anatomy, with access obtained using the SVC only.⁵ Although the procedure was successful, the SVC-only approach limited catheter manipulation, prevented creation of an LA electroanatomic map (EAM), and may preclude ablation of certain non–pulmonary vein triggers.⁵ Here, we report a case of AF ablation in a patient with dextrocardia in the setting of CSI with interrupted IVC and azygos continuation into a persistent left-sided SVC, using transhepatic access. Our approach facilitated complete EAM of the LA, bilateral PVI, and ablation of AF triggers from the persistent left-sided SVC.

To maintain a consistent convention, we attribute sidedness to morphology for all structures (ie, the atrium draining the hepatic vein is referred to as the right atrium [RA] even though it is on the patient’s left side), except for the vessels of the neck and groin (ie, the right femoral vein is the femoral vein on patient’s right side).

Case report

A 73-year-old female patient with a history of dextrocardia with CSI and interrupted IVC, sick sinus syndrome status post dual-chamber pacemaker, and symptomatic paroxysmal AF presented for catheter ablation.

She was first diagnosed with dextrocardia with CSI at age 6 during a routine school physical. She lived a normal childhood and early adult life until the development of AF 5 years prior to the current presentation. Given longstanding sinus bradycardia it was felt she would not tolerate medical therapy for AF, so a dual-chamber pacemaker was implanted, followed by cardioversion and initiation of metoprolol. She continued to have episodes of paroxysmal AF so was started on flecainide. In the setting of breakthrough episodes, transcatheter AF ablation was discussed, but given her complex anatomy a surgical maze procedure was recommended instead. She sought a second opinion at our institution. Although the presence of a pacemaker would allow for potential atrioventricular node ablation, given paroxysmal AF and no prior attempts at ablation, the decision was made to attempt catheter ablation as a first step.

A vascular-phase computed tomography scan including the chest, abdomen, and pelvis was used for procedural planning, confirming dextrocardia with CSI, and interrupted IVC. The azygos continuity of the IVC formed a persistent left-sided SVC, which drained into the coronary sinus (Figure 1A–1C).

Figure 1.

Baseline axial imaging. Depicted is the patient’s baseline axial imaging demonstrating key anatomical considerations, namely dextrocardia with complete situs inversus and interrupted inferior vena cava. A: Axial image at the level of the mid left atrium (LA). B: Axial image at the level of the upper LA. C: Coronal image showing the contiguous relationship between the common hepatic vein and the lower right atrium. Sidedness of chambers and vessels is attributed according to morphology (eg, RA denotes the morphologic right atrium, which is on the left). AO = aorta; IVC = inferior vena cava; LV = left ventricle; LSVC = left superior vena cava; RA = right atrium; RSVC = right superior vena cava; RV = right ventricle.

We performed the procedure under general anesthesia with assistance of the EnSite Precision impedance-based mapping system (Abbott, St. Paul, MN). To facilitate a procedural workflow requiring no changes in patient positioning, we performed the entire procedure from the patient’s left side, using the opposite of the typical operator hand positioning. Given continuity between the hepatic veins and the right atrium, we obtained transhepatic access with the assistance of the interventional radiology service (Figure 2E). Access to the right hepatic vein was obtained using direct ultrasound guidance and a 21 gauge 15 cm Chiba needle with an inner stylet. The stylet was removed and a 0.018-inch Cope wire was inserted with fluoroscopy confirming entry into the RA. A 6F AccuStick 2 trocar/catheter assembly was advanced over the Cope wire, which was exchanged for a 0.035-inch J-wire, over which a 14F 10 cm sheath was inserted. Using the modified Seldinger technique with a 21 gauge micropuncture needle and direct ultrasound guidance, venous sheaths were placed in the right common femoral vein and the left internal jugular vein. Intravenous heparin was administered to target an activated clotting time above 250 seconds.

Figure 2.

Hepatic access, transseptal puncture, and catheter positioning. Depicted are ultrasound, fluoroscopic, and intracardiac echocardiographic images displaying hepatic access, transseptal puncture, and postpuncture catheter positioning. A: The steerable transseptal sheath positioned high in the right-sided superior vena cava in preparation for a pull-down to the fossa ovalis. B: Transseptal sheath at the fossa ovalis with the transseptal wire having just crossed the septum into the left atrium (LA). C: Catheter position used during ablation, with a 20-pole catheter in the coronary sinus (continuous with the left-sided superior vena cava), and the ablation catheter within the steerable sheath sitting in the left superior pulmonary vein. D: Final positioning of the hemostatic coils deployed following removal of the hepatic vein sheath. E: Ultrasound image of the hepatic access procedure, with the access needle (bright white, arrow) visualized within a right-sided hepatic vein. F: Intracardiac echocardiogram (ICE) view from the internal jugular used to guide transseptal puncture, at the level of the thin portion of the fossa ovalis. G: ICE view used during ablation, with a view of the LA obtained from posteriorly with the ICE catheter in the azygos continuity of the inferior vena cava. The mapping catheter “Grid” can be seen in the right superior pulmonary vein (RSPV). AO = aorta, RA = right atrium.

The AcuNav intracardiac echocardiography (ICE) catheter (Siemens Healthineers, Erlangen, Germany) was advanced to the heart via the left internal jugular vein sheath, and the interatrial septum was visualized. A VersaCross Steerable Sheath medium curl (Baylis Medical, Montreal, Canada) was advanced through the transhepatic sheath and inserted into the RA over a straight guidewire. The guidewire could not be manipulated into the SVC, so the Advisor HD Grid mapping catheter (Abbott) was manipulated into the SVC and used to advance the sheath to the SVC (Figure 2A). The VersaCross transseptal wire and dilator were then inserted into the sheath and the entire apparatus was pulled down until tenting on the fossa ovalis was observed using real-time ICE guidance (Figure 2F). The apparatus was manipulated to achieve transseptal puncture at the mid fossa at the level of the pulmonary veins (Figure 2B). Radiofrequency energy was applied to the VersaCross wire, which was used to cross the septum and advance the sheath into the LA (Figure 2C).

The ICE catheter was removed from the internal jugular vein and advanced through the right femoral vein sheath into the azygos vein continuation of the IVC, which provided a view of the LA from the posterior side (Figure 2G). A 20-pole deflectable coronary sinus catheter (LiveWire; Abbott) was inserted into the left internal jugular vein sheath and advanced into the coronary sinus, which again was noted to be continuous with the azygos vein continuation of the IVC.

We inserted the HD Grid mapping catheter into the steerable sheath and created an EAM of the morphologic LA, which confirmed complete dextrorotation of the heart, with the left atrial appendage located adjacent to the pulmonary veins on the patient’s right side (Figure 3A and 3B). Left atrial bipolar voltage was largely normal (Figure 3C). We exchanged the mapping catheter for the 3.5 mm TactiCath D-F curve irrigated ablation catheter (Abbott). Using the ablation catheter, we performed wide antral circumferential ablation around the right- and left-sided pulmonary veins. Lesions were performed at 40 W, targeting a lesion size index of 4.0–4.5 on the posterior wall and 5.0–5.5 on the anterior wall. Esophageal temperature monitoring was performed, with moderate heating observed during the posterior portion of the left pulmonary vein lesion set. There was first-pass isolation of the right-sided veins, with additional ablation required over the left posterior carina following the initial lesion set to achieve isolation of the left-sided veins. Bipolar pacing at 10 mV from within the veins was used to confirm exit block. Two boluses of 6 mg intravenous adenosine were given, with induction of atrioventricular block but no pulmonary vein reconnection.

Figure 3.

Left atrial electroanatomic map and final lesion set. Panels depict electroanatomic maps (EAMs) and registered computed tomography (CT)-based projections of the case. A, B: Projections of the EAM generated using mapping (left) and the corresponding 3-dimensional CT image (right) in posteroanterior and right anterior oblique views, respectively. C: EAM with overlaid sinus voltage in posteroanterior (left) and right anterior oblique (right) views (see scale bar on left). D: EAM with the final lesion sets in posteroanterior (left) and right lateral (right) views. Red points are ablation lesions and yellow points are areas of phrenic nerve capture. The blue dot is the location of the clinical premature atrial contraction targeted following pulmonary vein isolation. CS = coronary sinus; LA = left atrium; LSVC = left superior vena cava; LV = left ventricle; RA = right atrium; RV = right ventricle.

We then started an isoproterenol infusion titrated to achieve a heart rate above 100 beats per minute. During isoproterenol infusion, we noted regular occurrence of a monomorphic premature atrial contraction (PAC), with earliest activation on the coronary sinus catheter. We targeted this area for ablation. We advanced the ablation catheter through the left internal jugular vein sheath through the coronary sinus into the persistent left-sided SVC. We delineated the course of the phrenic nerve with pacing. We performed focal ablation targeting areas of earliest activation of the PAC, which were on the anterior and septal aspect of the left-sided SVC away from the phrenic nerve (Figure 3D). We then positioned the ablation catheter on the opposing surface of the left upper pulmonary vein and placed a few lesions here. With further observation, there were no recurrences of the targeted PAC.

We removed catheters from the heart. With the assistance of the interventional radiology service, a pullback venogram was performed to determine appropriate positioning for coil placement. The parenchymal tract was then embolized using 2 8 mm × 24 cm detachable coils (Terumo Corp, Tokyo, Japan) delivered from a 5F Kumpe catheter. Hemostasis was confirmed with postcoil contrast injection and a postprocedure ultrasound showed no hematoma. Final coil positioning is shown in Figure 2D. Total procedure time was 6 hours 1 minute, and fluoroscopy time 35 minutes.

Following ablation, the patient was observed in the hospital for 1 night, with no complications. Blood counts were stable the following morning, and anticoagulation with rivaroxaban was resumed on the evening of postprocedure day 1. There was a self-limited episode of AF beginning on postprocedure day 1, which terminated spontaneously. The patient was discharged, with no clinical recurrence of AF at 2 months postprocedure.

Discussion

Here, we report successful AF ablation in a patient with rare anatomic variation, namely dextrocardia accompanied by CSI and interrupted IVC with azygos continuation into a persistent left-sided SVC. The keys to our procedure included a transhepatic access approach, transseptal puncture guided by ICE from the internal jugular vein, and inverted room and operator/patient positioning.

By more closely approximating typical anatomic relationships, we submit that our transhepatic access approach facilitated procedural success by supporting more facile sheath and catheter manipulation. A prior report of AF ablation in a patient with similar anatomy used an SVC-only approach⁵ but reported difficulty with catheter manipulation, which ultimately prevented creation of an EAM, a key component of contemporary AF ablation critical for defining LA substrate.⁶ Other reports of AF ablation in patients with interrupted IVC (without dextrocardia) have described complete mapping and ablation using an SVC-only approach, although atypical catheter positioning may be required.⁷ In contrast, transhepatic access has been described for procedures requiring transseptal access to the LA,⁸ although we are unaware of prior reports in patients with dextrocardia and CSI. In this case, our transhepatic access strategy provided more standard catheter manipulation, facilitating creation of a complete left atrial EAM, which confirmed normal bipolar voltage. Although it was not indicated for the current case, we suspect that our procedural setup would have facilitated ablation of non–pulmonary vein AF triggers located anywhere within the LA. Using hemostatic coils, we were able to resume full-dose anticoagulation after 24 hours when blood counts were confirmed to be stable, consistent with prior reports of transhepatic access in which anticoagulation has generally been resumed between zero and 48 hours postprocedure.9, 10, 11 Future reports will be useful to assess whether setups analogous to ours enable ablation of LA targets outside the pulmonary veins, targets within the left ventricle, or more facile AF ablation using emerging “single-shot” technologies.¹²

Following PVI, we noted PACs that seemed to originate from the persistent left-sided SVC. The left-sided SVC is the embryological precursor of the ligament of Marshall, a known potential trigger for atrial arrhythmias.¹³ Consistent with these prior reports, we observed unifocal PACs with earliest activation on the anterior and septal surface of the persistent left-sided SVC, which we were able to ablate from both sides of the septum. Following ablation, there was complete abolition of inducible PACs.

Importantly, by performing the entire procedure from the patient’s left side, we leveraged a procedural workflow that required no changes in the positioning of the patient or equipment. However, our setup also required inversion of the usual operator/patient relationship and hand positioning. An alternative approach would have been to move to the patient’s right side following transhepatic access, although we would have had to reposition equipment and, potentially, the patient, and operator access to catheters may be challenging depending upon patient body habitus. Although we found it was fairly straightforward to achieve all necessary catheter movements from the opposite side using nverted hand positioning, we submit that the relative advantages of our approach, balanced against the need for inverted hand positioning, should be considered on a case-by-case basis.

Conclusion

Transhepatic access through the left-sided liver is a safe and effective approach to PVI in a patient with dextrocardia with CSI and interrupted IVC with azygos continuation into a persistent left-sided SVC.