Sometimes Surgery is the Only Way to Make a Diagnosis and Treat the Patient: A Case of Congenital Partial Absence of Pericardium

Introduction: A 47-year-old Caucasian woman with a past medical history of multiple ablative procedures for supraventricular arrhythmias and pacemaker implantation presented with increasing shortness of breath. The initial working diagnosis of the team treating her was ablation-induced pulmonary stenosis, especially after the recording of increased flow velocities through the right lower pulmonary vein.

Case presentation: The patient was alert and oriented, but obviously dyspnoeic. The vital signs were normal. The physical examination revealed a soft cardiac systolic murmur and the lungs were clear on auscultation. The electrocardiogram showed a pacemaker rhythm. The echocardiogram showed borderline normal global systolic function of the left ventricle and severe mitral regurgitation. The transoesophageal echocardiogram confirmed the above findings and revealed increased velocities through the right lower pulmonary vein. The working diagnosis of ablation-induced pulmonary stenosis was reinforced by the cardiac CT angiography. The patient was subsequently referred for surgical intervention. The intra-operative findings were both unexpected and impressive: congenital partial absence of the pericardium was responsible for herniation of the right chambers into the pleural space. Mitral regurgitation was attributed to failure of coaptation due to the very short surface of the leaflets. Extensive external fibrosis around the pulmonary veins caused the pulmonary vein stenosis.

Conclusion: The final diagnosis of a partial pericardial defect causing torsion and distortion of the heart chambers was made only at surgery. The consistent finding of pulmonary vein stenosis in the non-invasive modalities and the past medical history of ablations initially misleadingly led us to the assumption that they were related.

Learning points: The initial working diagnosis of ablation-induced pulmonary vein stenosis based on the patient's shortness of breath, severe mitral regurgitation, right lower pulmonary vein stenosis and past medical history of multiple ablative procedures, was incorrect.The finding that the cardiac silhouette was borderline displaced to the right, the mildly hypoplastic right lung and the borderline impairment of the global systolic function of the left ventricle, especially after coronary artery disease was ruled out, should have been given greater consideration.Cardiac computer tomographic images taken 7 years ago were used to assess the severity of the right inferior pulmonary vein stenosis; new medical technologies will provide even better diagnostic techniques.