Discussion
Cardiac pacemakers and defibrillators are cornerstones in the management of patients with heart rate and/or rhythm problems. There is a steady growth in the use of pacemaker and defibrillator therapy in the United States and across the world (1-3). Although commonly inserted with access through the left subclavian or cephalic vein, inadvertent entry through the subclavian artery can lead to iatrogenic complications, including thromboembolism. Quick diagnosis of this event is essential, as leaving the lead is associated with an increased risk of life-threatening thromboembolism. Thrombus formation on the lead can occur within days, and fibrous tissue may begin developing in just a few months (4).
There are several methods available to avoid the occurrence of such events. When subclavian vein puncture is attempted, the subclavian artery may also be punctured. Arteriography may be used to identify the accessed vessel. In addition, successful venipuncture may be observed as the guidewire advances into the inferior vena cava under fluoroscopy. If there are ventricular premature beats with right bundle branch block pattern soon after the guidewire enters the ventricular cavity, the possibility of the guidewire entering through the artery must be considered. After the pacemaker is implanted, correct positioning of the pacemaker may also be seen through ECG. Right ventricular pacing is indicated when ECG shows left bundle branch block appearance, while left ventricular pacing is seen in right bundle branch block patterns (5).
Removal of the lead is one solution to avoid thromboembolic events but comes with other complications. Extraction of transarterially placed leads is associated with high thromboembolic risk as well as risk of bleeding from the arterial entry site. Furthermore, lead removal can lead to ventricular perforation or cardiac tamponade, and may cause trauma to the aorta, aortic valve, and coronary arteries (6). Given the direct connection to systemic circulation, any lead manipulation can potentially lead to systemic embolization. Due to the unnecessary risks pertaining to surgical removal, conservative management with lifelong anticoagulation may be an acceptable alternative in chronically implanted left ventricular cavity leads.