Cardiac Sarcoidosis Presenting as Syncope due to Complete Heart Block

Abstract

Background Syncope is the result of cerebral hypoperfusion with underlying etiologies classified as neurally mediated, cardiac, or orthostatic hypotension. Risk stratification based on etiology of syncope is crucial since cardiac syncope is associated with increased morbidity and mortality and may have specific treatment options, whereas neurally mediated syncope and orthostatic hypotension are often benign and are treated with supportive care. It is estimated that 5-21% of syncope is of cardiac etiology. Signs and symptoms, listed with the associated positive likelihood ratio (+LR) that predict increased risk of cardiac syncope include age >35 at initial episode of syncope (3.3), history of existing heart disease (2.7-7.3), exertional syncope (1.4-15), syncope while supine (1.1-4.9), prodromal chest pain, dyspnea, or palpitations (1.9-3.8), cyanotic during episode (6.2), and abnormal ECG (2.3). Case Presentation A 50-year-old woman presented with syncope while walking up a flight of stairs. Syncope was preceded by palpitations, dizziness, and dyspnea. ECG demonstrated sinus rhythm, 1st degree AV block, RBBB, and LAFB without ischemic changes. CT Coronary revealed multiple perilymphatic pulmonary nodules with hilar lymphadenopathy concerning for sarcoidosis. Transthoracic echocardiogram showed normal LVEF of 66% and proximal septal wall thickening. On hospital day 2, the patient experienced syncope while supine with bradycardia to the 20s and hypotension to 70s/40s. Repeat ECG and showed complete heart block. The patient received emergent transvenous pacing along with IV dopamine and norepinephrine infusions. On hospital day 3, she received a permanent dual chamber pacemaker-defibrillator. She underwent fluorodeoxyglucose positron emission tomography (FDG-PET) and biopsy confirming the diagnosis of cardiac sarcoidosis. Discussion This case demonstrates the importance of recognizing signs and symptoms associated with high-risk cardiac syncope, which should prompt hospital admission and further diagnostic evaluation. After identifying cardiac syncope, it is important to determine the underlying cause which can be due to arrythmias or structural heart disease. This patient’s arrhythmogenic cardiac syncope was due to cardiac sarcoidosis, an infiltrative granulomatous disease that impacts multiple organs. Clinical manifestations of cardiac sarcoidosis occur in only 5% of patients and typically presents as conduction abnormalities, ventricular arrythmias, and heart failure. Diagnosing cardiac sarcoidosis is crucial to identify patients that will benefit from appropriate treatment.