Pseudonormal Position of an Atrial Pacemaker Lead Associated With a Contralateral Pneumothorax
Where Is the Atrial Lead?
An 83-year–old man with coronary artery disease was hospitalized for syncope due to sick sinus syndrome and underwent dual-chamber pacemaker implantation. An axillary vein was accessed using venography in the absence of a cephalic vein. A right ventricular screw-in lead (Medtronic 5076, Medtronic, Minneapolis, Minn) was inserted and placed easily in the right ventricular apex with a hydrophilic 0.038-inch guidewire retained. After positioning the right ventricular lead, an attempt to insert the sheath for the atrial lead over that wire proved challenging because of the narrow space beneath the clavicle. The guidewire became dislodged from the inferior vena cava to the superior vena cava and was readvanced into the right atrium using fluoroscopy in the anteroposterior view. A 7-French peel-away sheath was inserted, and the guidewire was removed. Then, a screw-in atrial lead (Guidant 4472, Guidant, Indianapolis, Ind) was advanced but encountered resistance at the junction of the brachiocephalic vein. The atrial lead was gradually advanced into the right atrium and positioned with acceptable sensing (1.0 to 1.4 mV), pacing threshold (2 V/0.4 ms), and resistance (457 Ω) values.
The next day, a posteroanterior chest x-ray revealed that an asymptomatic pneumothorax had occurred on the contralateral side of the implant (Figure 1A). An echocardiogram showed that no fluid had accumulated in the thorax or pericardial space. However, the lateral chest x-ray view revealed an unusual course of the atrial lead (Figure 1B). The atrial lead ran apart from the ventricular lead at the level of the superior vena cava, and the tip of the atrial lead was directed in a posterior fashion, as opposed to toward a right atrial appendage position. Subsequently, the pneumothorax improved without any intervention. ECG-gated 64-slice computed tomographic scan was performed with a 3-dimensional reconstruction (see online-only Data Supplement Movie), which showed that the atrial lead had perforated the left brachiocephalic vein and had advanced into the mediastinum (Figure 2A). The curved multiplanar reformation clearly showed that the atrial lead had coursed through the mediastinum and that the tip had perforated from the pericardium into the right thoracic cavity (Figure 2B).
Perforation by the atrial lead of the brachiocephalic vein would have resulted in a large hemothorax or hemopericardium. We speculated that the atrial lead had advanced into and perforated a small pericardial vein, allowing it to enter the pericardial space. Finally, the screw-in atrial lead had extruded out of the pericardium into the right thoracic cavity and resulted in a contralateral pneumothorax. Fortunately, the pneumothorax resolved. Repositioning of the lead was deferred because the procedure might well have resulted in a massive hemorrhage if the lead had occluded the perforation site. The patient has remained stable over 3 months of follow-up.
The online-only Data Supplement, which contains a movie, is available with this article at http://circ.ahajournals.org/cgi/content/full/117/17/2297/DC1.