Double Transseptal Access for Atrial Fibrillation Ablation in the Presence of Investigational Interatrial Shunt Device

Abstract

Transseptal access for atrial fibrillation ablation can be challenging in the presence of iatrogenically modified interatrial septum. We report the first described transseptal left atrial access for atrial fibrillation ablation in the presence of an investigational interatrial shunt device, performed in a patient with heart failure with preserved ejection fraction. (Level of Difficulty: Intermediate.)

Graphical abstract

A 71-year-old man with symptomatic persistent atrial fibrillation (AF) was referred for ablation. Initially rhythm-controlled with amiodarone, this was discontinued due to dyspnea and concern for lung toxicity. Dofetilide was not tolerated (skin rash), and sotalol failed despite cardioversion 6 months prior.

Learning Objectives

• •To illustrate AF as a common comorbidity in patients with HFpEF.
• •To recognize the potential for treating HFpEF with an IASD.
• •To describe how to safely obtain LA access for AF ablation in the presence of an IASD.

Past Medical History

This patient had clinically and echocardiographically established heart failure with preserved ejection fraction (HFpEF). Due to New York Heart Association functional class III symptoms despite optimal medical therapy, he received an investigational interatrial shunt device (IASD) (Corvia Medical Inc., Tewksbury, Massachusetts) to reduce his left atrial (LA) pressure. This was performed 2 years before referral, when the patient still maintained sinus rhythm. The IASD was percutaneously implanted across the fossa ovalis (FO), creating an iatrogenic left-to-right shunt (Figure 1). In addition, he had hypertension, coronary artery bypass 20 years prior, obstructive sleep apnea, and morbid obesity.

Figure 1.

Interatrial Shunt Device and its Fluoroscopic and Echocardiographic Appearance

The more prominent profile is directed toward the right atrium, whereas the flat side stays toward the left atrium. This can be appreciated fluoroscopically in left anterior oblique projection (C, black arrow), while its 8-mm lumen diameter is best appreciated in right anterior oblique projection (D, black arrow). Intracardiac echocardiography shows a region of the fossa ovalis amenable to transseptal puncture inferior to the interatrial shunt device (E, white arrow). Color Doppler imaging confirms patent interatrial shunt device (red flow demonstrates left-to-right shunt, F); this view also shows the prominent right atrial (RA) profile of the interatrial shunt device. LA = left atrium

Investigations

Because of persistent dyspnea after amiodarone discontinuation, extensive pulmonary testing was performed without evidence of interstitial lung disease. Cardiac evaluation showed clinical congestion with echocardiographic evidence of diastolic dysfunction and normal ejection fraction (65%), all consistent with HFpEF. Symptoms persisted despite optimal medical therapy (including aggressive blood pressure control and loop diuretics) and IASD.

Management

The decision was made to proceed with AF ablation with transseptal access adjacent to the IASD. Initial ICE survey revealed a well-defined segment of the FO inferior to the IASD (Figure 1E), amenable for transseptal access. Under ICE and orthogonal fluoroscopic guidance, the assembly, comprising a radiofrequency transseptal needle (NRG Transseptal Needle, Baylis Medical, Mississauga, Ontario, Canada) and a steerable sheath with dilator (Agilis, St. Jude Medical, Sylmar, California), was retracted from the superior vena cava toward the interatrial septum. After the location was confirmed to be on the FO (tenting on ICE) and inferior to the IASD, LA access was obtained (the needle was advanced to the LA using radiofrequency energy and used to rail the dilator, followed by the sheath) (Figures 2A to 2C). Using the same approach, second access was accomplished with a nondeflectable sheath (SL1 braided sheath, St. Jude Medical), in close proximity to the first access site (Figures 2D to 2F). No specific difficulties were noted during LA mapping and ablation; however, to minimize the risk of catheter entrapment in the IASD, the ablation catheter was used to define the left interatrial septum instead of the multipolar mapping catheter (Figures 3A to 3C). During catheter manipulation, we noted that an alternative access location (superior to or through the IASD) would have made right inferior pulmonary vein ablation very challenging. This is because the septal aspect of the RIPV was in very close proximity to the IASD, and the inferior edge of the RIPV was at the same cranio-caudal level as the lumen of the IASD (Figures 3D to 3F).

Figure 2.

Double Transseptal Access Performed Adjacent to Interatrial Shunt Device

First transseptal puncture performed inferior to the interatrial shunt device. The dilator is seen in the LA covering the needle in left anterior oblique projection (A) followed by placement of the deflectable sheath in the LA in right anterior oblique projection (B). The fluoroscopic relationship between the second transseptal sheath (white arrow) and the interatrial shunt device also can be appreciated on intracardiac echocardiography (C). The second transseptal access was performed inferior to the interatrial shunt device but slightly superior to the first transseptal access site, as seen fluoroscopically in left anterior oblique projection (D). Intracardiac echocardiography imaging shows tenting of the fossa ovalis adjacent to the interatrial shunt device (E). After double transseptal access, the relationship between the transseptal sheaths and the interatrial shunt device is shown on intracardiac echocardiography (F, white arrow showing SL1 sheath). Abbreviations as in Figure 1.

Figure 3.

Left Atrial Mapping and Ablation

The ablator can be seen touching the interatrial shunt device in right anterior oblique and left anterior oblique views (A and B) without any issues; the device corresponds to the low voltage area (red) on the electroanatomic map (C). The ablator position during ablation of the inferior edge of the right inferior pulmonary vein is shown fluoroscopically in right anterior oblique and left anterior oblique views (D and E). This site is immediately posterior to the interatrial shunt device and at the same cranio-caudal level as the device lumen. Electroanatomic reconstruction of the transseptal access site (white arrow) shows the distance to the right inferior pulmonary vein and its position inferior to the interatrial shunt device (F).

Discussion

In this report, we describe the first double transseptal access and AF ablation in the presence of a novel IASD implanted for managing HFpEF. Due to lack of effective treatments other than diuretics and comorbidity optimization (1), creation of an iatrogenic left-to-right interatrial shunt has been postulated to improve outcomes in patients with HFpEF by reducing left-sided filling pressures (2,3). This was the basis of the REDUCE LAP-HF I (Reduce Elevated Left Atrial Pressure in Patients With Heart Failure) trial, a phase 2 randomized, sham controlled trial in which 22 subjects were randomized to the intervention group, including our patient (4). Early reports suggesting reduction in mortality after IASD implantation (5), associated with nearly two-thirds prevalence of AF in patients with HFpEF (6), implies that the scenario described here may become increasingly common.

Given the expected challenges related to the presence of the IASD, we entertained direct LA access through the IASD given its internal diameter of 8 mm (24-F), therefore able to accommodate an ablation catheter with or without a deflectable sheath. Separate transseptal access was preferred because: 1) the prominent right atrial profile of the IASD (Figure 1F) could pose a challenge to negotiating the catheter through the device; 2) catheter and sheath manipulation through the device could lead to inadvertent traction and device dislodgement; and 3) direct access across the IASD would allow deployment of only 1 catheter in the LA, not ideal for AF ablation.

ICE was especially useful to identify part of the FO extending inferior to the IASD, through which the LA was accessed. Orthogonal fluoroscopy, particularly the right anterior oblique projection, showed the transseptal access anterior to the IASD (Figure 2B). This suggests a relatively posterior location of the IASD on the FO, explaining the close proximity between the device and the right inferior pulmonary vein.

Follow-Up

The patient was observed overnight and discharged home the next day without any complications. Since his ablation procedure and over a 10-month follow-up, there have been no arrhythmia recurrences and his sotalol has been discontinued.

Conclusions

This is the first report of successful double transseptal LA access for AF ablation in a patient with an IASD to treat HFpEF. Transseptal access adjacent to the device can be safely accomplished under ICE and orthogonal fluoroscopic guidance. Our observations may be helpful to cardiologists confronted with this scenario in the future as we expect more similarly treated patients with HFpEF to need catheter ablation for managing their AF.

Author Disclosures

This research was supported by the Richard T. & Angela Clark Innovation Fund in Cardiovascular Medicine. The authors have reported that they have no relationships relevant to the contents of this paper to disclose.