British Journal of Radiology (2003) 76, 211-212
© 2003 British Institute of Radiology
doi: 10.1259/bjr/64628028
A heart problem?
H M Tee, DMRD and
A T Carty, DMRD, FRCR
Department of Radiology, Royal Liverpool University Trust, Prescot Street, Liverpool L7 8XP, UK
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Introduction
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A 30-year-old woman presented with a 4-year history of intermittent central chest pain associated with dyspnoea. These symptoms were not related to exertion, changes of position or meals. Physical examination revealed normal pulse and blood pressure. The only positive finding was systolic ejection murmur at the second left intercostal space. Electrocardiogram showed normal sinus rhythm with right axis deviation. Frontal and lateral chest radiographs are shown (Figure 1
). A contrast enhanced CT scan was subsequently performed (Figure 2).
What do the chest radiographs and CT show? What is the diagnosis?
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Answer
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Frontal chest radiograph revealed displacement of cardiac silhouette to the left hemithorax, the right heart border is hidden by the spine and the trachea is central. The lower border of the heart appears elongated and flattened. Lateral chest radiograph showed protrusion of the heart posteriorly. CT scan through the great vessels showed interposition of lung between the ascending aorta and main pulmonary artery. Section through the heart demonstrated the abrupt termination of right pericardium and extreme intrathoracal posterolateral displacement of the heart. A diagnosis of congenital absence of left sided pericardium was made. Transoesophageal echocardiogram showed no cardiac anomalies but the unusual orientation of the heart was noted.
Congenital absence of the pericardium is rare. Fewer than 400 cases have been reported [1]. Absence of the pericardium can be either complete or partial, occurring more often on the left than the right side. Left sided complete absence of pericardium is the most common form. Total and right sided absences are very rare. The ratio of incidence in males and females is 3:1. The cause of this anomaly is attributed to premature atrophy of the left duct of Cuvier, resulting in a deficiency of blood supply to the left pleuropericardial membrane, which in adult life, forms the left pericardium. The right duct of Cuvier normally persists as the superior vena cava, ensuring adequate blood supply to the developing right pericardium. In 30% to 50% of the cases reported, pericardial defects are associated with congenital anomalies of the heart, lungs, chest wall, and diaphragm, such as patent ductus arteriosus, atrial septal defect, Tetralogy of Fallot, mitral stenosis, bronchogenic cysts, pulmonary sequestration, pectus excavatum, and diaphragmatic hernia [1, 2].
Unless there is an associated cardiac anomaly, the majority of patients are asymptomatic. When symptoms are present, the most common complaint is of non-specific chest pain, probably from the abnormal torsion or strain on the great vessels due to greater mobility of the heart. With partial pericardial defects, there is possibility of herniation of atrial appendage or left ventricle, with the potential for strangulation of the heart. Surgical repair is therefore generally recommended when a partial pericardial defect is diagnosed [1–3]. Complete left sided absence of pericardium is apparently without any lethal potential and does not require surgical intervention unless rare complication such as tricuspid valve insufficiency develops [1, 2].
Pericardial defects rarely cause symptoms and thus are not often recognized. Chest radiograph may raise suspicion. The radiographic findings in complete absence of left sided pericardium include cardiac displacement to the left hemithorax without tracheal deviation, interposition of a segment of lung between aorta and pulmonary artery, and between inferior border of the heart and left hemidiaphragm. In partial absence of pericardium, the heart is in a normal position and the abnormality consists of varying degree of prominence of pulmonary artery or left atrial appendage or both.
The differential for this include enlarged pulmonary artery, mitral disease with enlargement of the appendage, tumour of the hilum, pericardial cyst or the rare aneurysm of the appendage [3]. In the past, diagnosis of pericardial defect was established by the presence of pneumopericardium on induction of an iatrogenic left sided pneumothorax. This procedure is now obsolete with the availability of sensitive and non-invasive imaging modalities. CT or MRI is now used to confirm the diagnosis. In the absence of previous surgery or inflammatory episodes, the normal pericardium will always be imaged on CT as a continuous line of consistent and predictable thickness [4]. However, paucity of pericardial fat may prevent visualization [4, 5]. CT of our patient shows the characteristic findings of complete absence of left sided pericardium. Interposition of lung between the main pulmonary artery and ascending aorta is strongly suggestive of absent pericardium [1, 5].
Recognition of congenital pericardial defect is important because the chest radiograph may simulate different pathological conditions. The diagnosis and distinction between partial and complete left sided pericardial defects is essential as partial apical defect is potentially fatal.
Received for publication October 10, 2001.
Accepted for publication November 9, 2001.
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References
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- Van Son JAM, Danielson GK, Schaff HV, Mullany CJ, Julsrud PR, Breen JF. Congenital partial and complete absence of the pericardium. Mayo Clin Proc 1993;68:743–7.[Medline]
- Nasser WK, Helmen C, Tavel ME, Feigenbaum H, Fisch C. Congenital absence of the left pericardium. Circulation 1970;41:469–78.[Abstract/Free Full Text]
- Bennett KR. Congenital foramen of left pericardium. Ann Thorac Surg 2000;70:993–8.[Abstract/Free Full Text]
- Baims RS, MacDonald IL, Wise DJ, Lenkei SC. Computed tomography of absent left pericardium. Radiology 1980;135:127–8.[Abstract/Free Full Text]
- McIlhenny J, Campbell SE, Raible RJ, Antaki GM. Pediatric case of the day. Congenital absence of the pericardium. AJR 1996;167:270,274–5.
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