Objectives Congenital absence of the pericardium (CAP) is often confused with other conditions presenting with right ventricular dilatation and usually warrants CT or cardiac MR (CMR) to confirm. It would be desirable to have more specific echocardiographic criteria to provide a conclusive diagnosis.
Methods 11 patients who were diagnosed with CAP (four patients with total CAP) based on CT/CMR were consecutively enrolled. Thirteen patients with atrial septal defect (ASD) and 16 normal subjects served as controls. To investigate spatial changes of heart in the thoracic cavity in CAP, following echocardiographic measurements were made in the left and right decubitus positions: the angle between the ultrasound beam and the left ventricular posterior wall (Angle-PW) in end-diastole at the parasternal long axis, and the distance between the chest wall and the most distal part of the left ventricular posterior wall (Distance-PW) at the parasternal mid-ventricular short axis.
Results Angle-PW in patients with CAP were significantly greater than in those with ASD (100.1±12.5° vs 74.5±8.6°, p<0.017) or in normal subjects (100.1±12.5° vs 69.9±7.6°, p<0.017) at the left decubitus, and the difference in Angle-PW according to posture (left vs right) was significantly greater in CAP compared with the other groups (CAP 20.7±12.7°, ASD 0.31±1.80°, normal 0.31±1.40°, all p<0.017). The differences in Distance-PW according to patient position (CAP 2.43±0.77°, ASD 0.42±0.45°, normal 0.26±0.55°) or cardiac cycle in each position (left: CAP 1.60±0.76°, ASD 0.41±0.27°, normal 0.17±0.12°; right: CAP 0.70±0.32°, ASD 0.22±0.19°, normal 0.22±0.13°) were significantly higher in the CAP group than in the other groups (all p<0.017).
Conclusions Patients with CAP have dynamic alteration in cardiac position depending on posture, which is not observed in ASD or in normal controls. Hence, total or left-sided CAP can be reliably diagnosed with positional changes during routine echocardiography.
- congenital pericardial absence
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Contributors MJK and H-KK contributed to the conception and design, acquisition of data or analysis and interpretation of data. J-HJ, J-BP, Y-JK, G-YC and D-WS contributed to the conception and design, and acquisition of data. J-HJ, YEY, H-LK contributed to the analysis and interpretation of data. MJK and H-KK contributed to the drafting and finalising the article. J-HJ, YEY, S-PL, Y-JK, G-YC, D-WS and JKO contributed to the revision of the article critically for important intellectual content. All authors provided final approval of the version to be published.
Funding This study was partly supported by Chong Kun Dang Research Fund 2016.
Competing interests None declared.
Patient consent Study patients provided written informed consent to participate in the study.
Ethics approval The study protocol was approved by the Institutional Review Board of Seoul National University Hospital.
Provenance and peer review Not commissioned; externally peer reviewed.