Isolated Right Ventricular Cardiac Sarcoidosis Presenting as Complete Heart Block

Abstract

Introduction Sarcoidosis is a multi-organ disease with formation of granulomas. Involvement of the heart causes inflammation, leading to atrioventricular block (AVB) or ventricular arrhythmias, and portends a poor prognosis. Cardiac sarcoidosis is detected in only 2% of patients, and most have left ventricular (LV) involvement. Isolated right ventricular (RV) involvement is rare. High suspicion is necessary to make the diagnosis, and advanced testing is required. Recognizing cardiac sarcoid is imited to the RV and determining presence of pulmonary hypertension (PH), is imperative for management. Case Presentation A 53 yo woman presented with dyspnea and palpitations. She has a history of complete heart block (CHB) requiring permanent pacemaker placement, and atrial arrhythmias. On evaluation, BP 153/81 mmHg and HR 71 bpm. Physical exam was normal. Given clinical history and refractory dyspnea, there was concern for an inflammatory process. Cardiac monitoring revealed frequent premature ventricular contractions (PVCs) and non-sustained ventricular tachycardia (NSVT). An echocardiogram demonstrated normal valvular and LV function, but the RV was severely dilated with moderate dysfunction. A right -heart catheterization (RHC) demonstrated normal pulmonary artery pressures and pulmonary capillary wedge pressure. A nuclear PET scan showed areas of increased FDG uptake within the RV, distal anteroseptal LV and pericardium, concerning for sarcoidosis. An endomyocardial biopsy (EMB) demonstrated multinucleated giant cells, confirming sarcoidosis. The patient underwent radiofrequency ablation for AFL. Her device was upgraded to a defibrillator. She was initiated on Cellcept. Serial echocardiograms revealed no PH and stable RV size and function. Case Discussion The diagnosis of cardiac sarcoidosis is elusive due to non-specific signs and symptoms. It often presents with CHB, ventricular arrhythmias or sudden death, atrial arrhythmias, or heart failure. Our patient was diagnosed with CHB, then went on to develop atrial and ventricular arrhythmias, and RV failure. The majority of patients with cardiac involvement have LV involvement. There are only a few case reports of isolated RV involvement. Since lone RV cardiac sarcoidosis is uncommon, diagnosis is delayed. Fortunately in our patient, once sarcoidosis was confirmed to be primarily involving the RV, a RHC and serial transthoracic echocardiograms were performed to rule out PH, which would influence treatment. Conclusion Cardiac sarcoidosis is rare, identified in only 25% of patients with systemic sarcoidosis, and has a poor prognosis. A high degree of suspicion is warranted, especially among young patients with arrhythmias of unclear etiology. Further investigation with serologic ACE levels, imaging such as cardiac magnetic resonance imaging (CMR) or nuclear PET scan, and EMB should be done. Finally, periodic echocardiograms and RHCs are necessary to ensure PH does not develop, which has implications for management.