A previously healthy 44-year-old Caucasian man presented with recurrent syncope and was found to have a complete heart block with a ventricular rate of 24 bpm. No biochemical abnormalities were identified. Tick borne illnesses were ruled out. Paced echocardiogram revealed left ventricular systolic dysfunction with septal hypokinesis. Chest radiography and subsequent CT scan did not reveal adenopathy. However, a positron emission tomography scan demonstrated increased fluorodeoxyglucose uptake in the spleen, a right retro-clavicular lymph node, right ventricle and the interventricular septum of the heart. Excision biopsy of the retro-clavicular lymph node revealed non-caseating granulomas consistent with sarcoidosis. Complete heart block persisted despite steroid treatment. A pacemaker/biventricular implantable cardioverter defibrillator was placed for complete heart block and primary prevention of ventricular tachycardia and sudden cardiac death.
Double blind crossover comparison of the effects of dual chamber pacing (DDD) and ventricular rate adaptive (VVIR) pacing on neuroendocrine variables, exercise performance, and symptoms in complete heart block.
