Clinical History
The patient was admitted to the hospital for investigation of chest pain on exercise of about four years duration. On physical examination, the apical cardiac pulsation was felt lateral to the left midclavicular line towards the anterior axillary line. An electrocardiogram showed a normal sinus rythm at a rate of 72 beats per minute, a deviation of QRS axis to 30 degrees and an incomplete right bundle branch. Reading the routine chest radiographs, the radiology resident felt that something was abnormal with
this thorax and called for the chest radiology fellow. His diagnosis was confirmed by MRI.
block.
Imaging Findings
The patient was admitted to the hospital for investigation of chest pain on exercise of about four years duration. On physical examination, the apical cardiac pulsation was felt lateral to the left midclavicular line towards the anterior axillary line. An electrocardiogram showed a normal sinus rythm at a rate of 72 beats per minute, a deviation of QRS axis to 30 degrees and an incomplete right bundle branch block. Reading the routine chest radiographs, the radiology resident felt that something was abnormal with this thorax and called for the chest radiology fellow. His diagnosis was confirmed by MRI.
Discussion
The true incidence of pericardial defects is unknown. Less than 250 cases are reported in the literature and the condition is observed in approximately one in every 10.000 autopsies. Widespread use of cross-sectional imaging modalities and increased surgical intervention in the thorax, however, suggest that these defects are probably much more common than previously assumed. There is a male preponderance of 3:1. Absence of the pericardium may be total, partial or focal and occurs predominantly at the left side. In about one third of cases, the defect is associated with other congenital cardiopulmonary abnormalities, such as atrial or ventricular septal defects, persistent ductus arteriosus, aortic valve anomalies, tetralogy of Fallot, bronchopulmonary sequestration and others. Pathophysiologically, the anomaly seems to be related to a premature atrophy of the left cardiac vein (left duct of Cuvier), leading to a loss of blood supply to the left pleuropericardial membrane, which normally persists and forms the left pericardium in the adult. Definite diagnosis can be made with CT scan or MRI, showing abrupt termination of the right pericardium or total absence of pericardium, cardiac rotation, shift to the left hemithorax and interposition of lung between the aortic arch and the main pulmonary artery. Sometimes there may be visualization of the ligamentum arteriosum due to herniation of lung engulfing the separated aortic arch and pulmonary trunk. Most commonly, absent left pericardium causes no symptoms and requires no treatment as it does not influence life expectancy. In up to one third of patients, however, chest pain may occur, probably as a result of torsion of the great vessels or due to pleuropericardial adhesions. In rare cases, death has been reported, probably due to herniation of the left atrium or its appendage through a small left-sided pericardial defect.
Differential Diagnosis List
Congenital Absence of Left Pericardium
Final Diagnosis
Congenital Absence of Left Pericardium
