MUSEUM OF HMH MULTIMODALITY IMAGING CENTER
Vosko I, Zhan Y, Nabi F, Zoghbi WA. Snoopy’s Heart: A Case of Complete Congenital Absence of the Pericardium. Methodist DeBakey Cardiovasc J. 2019;15(3):226-7.
congenital absence of the pericardium , adult congenital heart disease , ACHD , echocardiography , computed tomography
A 52-year-old male presented to our facility with dyspnea and dizziness. His past medical history was significant for smoking and hyperlipidemia. An electrocardiogram (ECG) showed a normal sinus rhythm, a rightward axis, low voltage, and poor R-wave progression (Figure 1 A). Transthoracic echocardiography revealed an abnormal atrial-ventricular axis; however, it was difficult to image the heart from the usual parasternal long axis because the apex was shifted laterally and posteriorly and the atria was elongated (Figure 1 B). In addition, the chest x-ray displayed levoposition of the heart with an obscured right heart border, an elongated and flattened left heart border (“Snoopy sign”),1 and a radiolucency between the main pulmonary artery and aorta (Figure 1 C).
Consequently, the patient underwent computed tomography (CT) to determine if there was a congenital absence of the pericardium (CAP). The CT confirmed the leftward displacement of the heart and the absence of the pericardial layer (Figure 1 D). An interposition of lung tissue between the main pulmonary artery and the aorta—a characteristic sign for CAP—could be seen in the axial view (Figure 1 E).2
Congenital absence of the pericardium is a very rare disease that can be categorized as a complete or partial absence of the pericardium, with the latter having a higher risk for complications.3 Often found incidentally, CAP has a nonspecific clinical presentation, with possible symptoms being chest pain, dizziness, and shortness of breath. In our case, the diagnosis was suspected because of the unexplained shifted heart position in the chest.
Although CT and magnetic resonance imaging are the gold standard for diagnosing CAP,4 certain findings on an ECG, echocardiography, and chest x-ray can also indicate its presence.2 Nevertheless, the rarity of CAP can make it difficult to detect; therefore, clinicians should familiarize themselves with the different findings that can lead to a prompt diagnosis.References
- Panagiotopoulos N, Barnard J, Wells F. The Snoopy sign. Eur J Cardiothorac Surg. 2014 Mar;45(3):586.
- Lopez D, Asher CR. Congenital Absence of the Pericardium. Prog Cardiovasc Dis. 2017 Jan – Feb;59(4):398-406.
- Shah AB, Kronzon I. Congenital defects of the pericardium: a review. Eur Heart J Cardiovasc Imaging. 2015 Aug;16(8):821-7.
- Kim MJ, Kim HK, Jung JH, et al. Echocardiographic diagnosis of total or left congenital pericardial absence with positional change. 2017 Aug;103(15):1203-1209.