Premature Ventricular Contraction Ablation In A Heart Transplant Recipient With Interrupted Inferior Vena Cava- Transfemoral Approach With Azygos Vein Detour

Authors: Jakrin Kewcharoen MD¹, Jalaj Garg MD¹, Tahmeed Contractor MD¹, Ravi Mandapati MD FHRS¹, Rahul Bhardwaj MD¹

Background: We present a case of a 28-year-old woman with interrupted inferior vena cava (IVC) with azygous vein continuation who underwent ablation of premature ventricular contraction (PVC) in the right ventricle (RV) with access to the right atrium (RA) via the azygous vein and superior vena cava (SVC).

Case presentation: A 28-year-old woman with a past medical history of congenital single ventricle status post orthotopic heart transplantation (OHT) at one-year-old presenting with recurrent palpitation, with a 10% PVC burden on a 14-day ambulatory electrocardiogram (ECG) monitor.  As such decision was made to proceed with PVC ablation. There was difficulty advancing the catheters into the RA during the ablation procedure via transfemoral approach.

The short femoral vein sheath was exchanged for a long sheath, and a contrast injection was performed that demonstrated an interrupted IVC. Contrast traversed to the azygous vein and eventually drained into superior vena cava SVC and RA (Panel A). A force-sensing irrigated ablation catheter was then advanced via the long sheath into the RV (Panel B). The activation map for the clinical PVC was performed that demonstrated the earliest activation along the lateral aspect of the moderator band and RV free wall (27 msec pre-QRS). Single ablation lesion terminated the PVC (Panels C and D). The rest of the procedure was uneventful, without any complications, and the patient was subsequently discharged with standard hospital protocol. A repeat ambulatory ECG monitoring demonstrated a PVC burden of <1%. The patient had been symptom-free ever since the ablation.

Interrupted IVC is a rare congenital defect with a reported incidence of 1 in 5,000 (1). During fetal development, fusion of paired cardinal veins forms four segments of IVC (hepatic, suprarenal, renal, and infrarenal).  Failure of subcardinal veins to form the suprarenal segment of IVC leads to interruption of IVC. The azygous vein system is developed separately via the supra cardinal veins and thus may develop normally and connects to the SVC. Therefore, venous blood that failed to go through the IVC will be drained to the azygos vein instead, resulting in venous dilatation (due to an increased venous flow).

Interruption of IVC poses a challenge in procedures that needs access to the right heart via the femoral vein approach. Nevertheless, the dilated azygous vein provides an alternative access to the right heart. Previous case reports of patients with interrupted IVC undergoing EP procedures for supraventricular arrhythmias ablation and left atrial appendage occlusion were done with mixed of upper extremity venous access or femoral access with azygous vein continuation (2,3). We added into the literature the first case of ventricular arrhythmias ablation in a patient with interrupted IVC.  In our case, we were able to pass the long sheath and an ablation catheter safely via the azygous vein into the RA and RV. Activation mapping of the PVC and single-lesion ablation of lateral moderator band and RV free wall was uneventful and without complications.

References:

1. Hardwick T, Belcher E, Sabharwal T, King J. Interrupted inferior vena cava: high-risk anatomy for right thoracotomy. Interact Cardiovasc Thorac Surg 2011;12:850-2.
2. Hanley A, Bode WD, Heist EK et al. Management of patients with interrupted inferior vena cava requiring electrophysiology procedures. J Cardiovasc Electrophysiol 2020;31:1083-1090.
3. Pérez-Silva A, Merino JL, Peinado R, Lopez-Sendon J. Atrial flutter ablation through the azygous continuation in a patient with inferior vena cava interruption. Europace 2011;13:442-3.