Congenital absence of the pericardium (CAP) is an uncommon finding previously recognized only post-mortem or during surgery. However, its incidence has been on the rise with the use of multiple contemporary imaging techniques. CAP can present with paroxysmal, left-sided chest pain and should be considered in the differential diagnosis of atypical causes of chest pain. We present the case of a 50-year-old male who presented with chest pressure, symptoms of heart failure, and was found to be in atrial fibrillation in whom partial absence of the left pericardium was diagnosed.

Case Presentation

A 50 year-old African-American male presented to the Emergency Department with a chief complaint of shortness of breath (SOB) and worsening dyspnea on exertion for one week. He described worsening SOB when lying on his left side, as well as palpitations, orthopnea, and non-radiating, left-sided chest pressure. On physical exam, the patient was tachycardic with an irregularly irregular heart rate, crackles in the lower lobes, trace bilateral lower extremity edema, and a non-palpable apical impulse. Laboratory studies were significant for a pro-B-type natriuretic peptide (pro-BNP) level of 2830 pg/mL (normal range = <100 pg/mL) and negative troponins. Electrocardiogram (ECG) showed a ventricular rate of 146 beats per minute, irregularly irregular rhythm, right axis deviation, and poor R-wave progression. Chest x-ray (CXR) (Figure 1) revealed cardiomegaly and a diminished right heart border. Subsequent echocardiogram showed severe mitral regurgitation and moderate tricuspid regurgitation. Of note, it also showed the heart shifted posteriorly in the apical window, suspicious for congenital absence of pericardium. CT scan confirmed the diagnosis of partial absence of the left pericardium.