Large Right Atrial Thrombi Surrounding Permanent Transvenous Pacemakers

Transvenous pacemakers offer advantages but may also lead to complications not seen with transthoracic pacemakers. We have seen two patients in whom at autopsy large right atrial thrombi were found around the catheter. The first patient had signs of increasing right heart failure and oliguria and died 48 hours after implantation of the pacemaker, which functioned normally throughout. At autopsy 80% of the right atrium was filled by a thrombus. This thrombus had caused inadequate filling of the right atrium and seemed responsible for the deterioration and death of the patient. The second patient died suddenly 2 months after insertion of the pacemaker after suprapubic prostatectomy. At autopsy a well-organized thrombus encircled the catheter between the junction of the azygos vein and the superior vena cava to the tricuspid valve. The thrombus may have caused signs of right heart failure before death. Since right atrial thrombi may be detected by angiography and treated by surgery, it is important to be aware of this rare complication of transvenous pacing.