Electrophysiology Study and Catheter Ablation With Superior Vena Cava Stump

A 39-year-old female patient had a 3-year history of atrial fibrillation, atrial flutter, and transient ischemic attack, for which she was anticoagulated with dabigatran etexilate (Boehringer Ingelheim Pharmaceuticals). During an initial diagnostic electrophysiology study, despite multiple attempts, a wire would not advance into the right atrium via the left axillary vein approach. This was abandoned and femoral venous access was used to obtain access to the right ventricle and coronary sinus. She then underwent an uneventful atrial flutter ablation. 

 

At the time of staged pulmonary vein isolation, contrast was injected to confirm the presence of a blind pouch at the right atrial roof, suggesting the absence of a patent superior vena cava (SVC) (Figure 1A). Transseptal puncture was then performed with both transesophageal echocardiographic and fluoroscopic guidance. Cardiac computed tomography scan confirmed the absence of the SVC. A dilated azygous vein and a prominent collateral vein were demonstrated to divert venous return from the terminus of the left brachiocephalic vein to the inferior vena cava and right atrium, respectively (Figures 1B and 1C). 

 

Absent right SVC is usually accompanied by a persistent left SVC.¹ We report the complete absence of an SVC in a patient without prior history of cardiac surgery or device implantation. This is a very rare congenital cardiac abnormality, which if unrecognized, may lead to complications in patients undergoing electrophysiological studies.^2,3