Case report: recurrent thrombosis of an old lead of a DDDR pacemaker mimicking lead infection

INTRODUCTION: Thrombosis of the intracardiac part of a permanent pacemaker lead, which is usually detected during a routine transthoracic echocardiographic examination, can be totally asymptomatic. The differential diagnosis between intracardiac lead thrombosis and vegetation is crucial, especially in febrile patients, as these two situations are totally different regarding prognosis and treatment. CASE PRESENTATION: We describe the case of an 85-year-old patient with a dual chamber pacemaker (DDDR) due to complete heart block, who was admitted twice, within 2 years, with vegetation-like masses attached to the ventricular lead of the pacemaker. Infective endocarditis was not documented (diagnostic criteria were not fulfilled), although clinical suspicion was high during both hospitalizations. Masses resolved under applied treatment (anticoagulation) in both cases. DISCUSSION: Differential diagnosis between lead thrombosis and vegetation was ambiguous in both hospitalizations. Τhe (18)F-fluorodeoxyglucose positron emission tomography/computed tomography during the 2nd hospitalization excluded a possible inflammatory origin of the masses.