1350868 - Uncovered Association: Absent Pericardium In A Case Of Hypertrophic Cardiomyopathy

A 14-year-old obese male with Blount’s disease presented for cardiac magnetic resonance imaging (CMR) evaluation of hypertrophic cardiomyopathy (HCM). He was born in Germany with a prenatal diagnosis of cardiac malposition with no intracardiac anomalies. He moved to the United States at the age of 7 years where he was seen by multiple physicians for chest pain, with challenging echocardiographic evaluation due to limited acoustic windows. He was diagnosed with HCM at the age of 12 years with a distorted right ventricle (RV) and increased left ventricular (LV) mass and posterior wall thickness by echocardiography.  

Diagnostic Techniques and Their Most Important Findings:

CMR evaluation showed extreme cardiac levoposition (figure 1) with abnormally elevated angle of clockwise rotation of 127 degrees. In addition, lung tissue was noted lying between the aortic root and main pulmonary artery (figure 2D) on axial balanced steady-state free precession and T1-weighted spin echo images. Complete absence of the parietal pericardium (CAP) was noted with increased prominence of epicardial fat, a blurry cardiopulmonary interface, and free-floating atrial appendages (figures 2 & 3). RV and LV sizes and systolic function were normal. There was mild LV hypertrophy with the thickest segment at the mid-ventricular inferolateral segment measuring 13 mm in comparison to the mid-septum at this level measuring 8.6 mm (figure 2B). The indexed LV mass measured 69 g/m2, with an abnormally elevated body surface area of 2.34 sq m. There was no late gadolinium enhancement.

Learning Points from this Case: This case highlights combined findings of CAP with HCM in a pediatric patient, which has hitherto not been reported. Our case demonstrates several key findings that point to the diagnosis of CAP, including increased cardiac rotation angle and lung tissue present between the aortic root and main pulmonary artery. Echocardiography is challenging in CAP due to shifted acoustic windows. Early use of CMR in patients with significant cardiac malposition can lead to early recognition and complete evaluation of other associated diseases such as HCM. CMR can provide useful guidance for optimal acoustic windows for required future follow up echocardiography exams.