Superior vena cava breach a severe complication or a benign entry?

Perforation at the level of the superior vena cava (SVC) and right atrium (RA) junction can be a lethal complication. Therefore, it is always prudent to advance the guide wire as well as the dilator with sheath under fluoroscopy. If a perforation occurs the lead will go out of the SCV-cardiac silhouette. This perforation is extra-pericardial and due to negative intra-thoracic pressure can cause rapid exsanguination. However, if this extra-cardiac course of the pacing lead was in a normal vascular conduit, undue emergent measures would not be instituted. Knowledge of the variation in cardiac anatomy is vital for the implant physician. We describe a 74 year old woman with symptomatic sinus node disease. Advancing the wire through the left subclavian vein (LSCV) proved challenging due to an inferior sharp dip that directed the wire superiorly. This was confirmed with IV contrast injection. First of the two guide wires was used and after removal of the dilator the RV lead was advanced after manipulation at the junction of the right atrium. The lead met resistance just above the diaphragm. A contrast injection in AP and LAO views confirmed a linear extra-cardiac course. The lead was pulled back and further contrast confirmed no leak into the extra-cardiac space. A nub of a vascular structure was noted in the LAO view. This was the “Azygos” vein opening into the SVC. The patient remained hemodynamically stable. A dual chamber pacemaker was successfully implanted and a post procedure echocardiogram revealed no pericardial effusion. Our case demonstrates that rarely the azygos vein can be entered and this can mimic vascular perforation. Knowledge of this would save the extra measures that would be undertaken in case of a vascular perforation at this level. Keywords: Azygos vein, vascular perforation, PPM implantatio