Pacemaker Dysfunction due to a Large Thrombus on Ventricular Lead

Pacemaker lead-related thrombosis is a rare but severe complication in patients with pacing lead implantation in the right ventricle. We present a case with recurrent syncope after single-chamber implantable cardioverter defibrillator (ICD) implantation. Pacing lead-related thrombosis was observed during open-heart surgery. This induced intermittent pacemaker dysfunction and recurrent syncope.

A 67-year-old male patient presented with frequent episodes of syncope and a history of dilated cardiomyopathy and paroxysmal ventricular tachycardia. Normal coronary angiography was found, and therefore a single-chamber ICD was implanted into the right ventricle to prevent cardiac events in 2013. However, he was referred to our hospital because of recurrent syncope 3 to 4 years after ICD implantation. A comprehensive investigation was performed to find out the etiology for the recurrent syncope. Pacing lead thrombosis was finally observed during open-heart surgery, which can introduce intermittent pacemaker dysfunction. After the thrombus was removed and the lead was separated from the posterior leaflet of the tricuspid valve, the ICD functioned normally after reprogramming. Oral anticoagulant was prescribed after discharging. During the 1-year follow-up period, this patient was free of syncope.

This case illustrated that pacemaker lead-associated thrombosis should be considered when the cardiac implantable electronic device fails to prevent patients from having cardiac events. Oral anticoagulant might be important for preventing thrombosis among patients with ICD implantation into the right ventricle.