Case 45
This radiograph demonstrates unusual but ultimately inconsequential pacemaker lead positioning. A dual chamber pacemaker generator pack projects over the left hemithorax. The right ventricular lead takes the expected course through the left brachiocephalic vein, superior vena cava, right atrium, and tricuspid valve and terminates in the expected position of the right ventricle. The right atrial lead, however, courses to the left of the aorta. There are no secondary signs to suggest an inadvertent extravascular course. The best explanation for this appearance is a persistent left superior vena cava. This is a normal variant and connects the left subclavian vein to the coronary sinus. Ultimately, the lead ends up in the right atrium. It is not clear in this case why this positioning was chosen rather than placing both leads in the right (normal) SVC.
The exam is otherwise unremarkable.