First described by Bailey in 1955, and first excised by Morrow and Behrendt in 1968 congenital right atrium aneurysm is a rare anomaly of unknown origin [8–11]. Several authors reported histological evaluation of resected aneurysmal tissue. The tissue can be normal or pathological . The variety of histological changes include fibrosis, focal lymphocytic infiltration, focular myxoid changes [9, 10, 12, 13]. Forbes et al. state that histological evaluation of resected aneurysmal tissue does provide information about the cause of the anomaly . In our case, the patient presented not only with arrhythmia, but also with cardiac tamponade, accompanied by marked histological pathology.
RAA can be asymptomatic or it can present with a variety of symptoms including supraventricular arrhythmias, formation of intraatrial thrombus and severe atrial dilatation. The most common one is supraventricular arrhythmias such as atrial fibrillation [1, 2, 5–7, 15]. It is not known why arrhythmias’ occur in such patients. As stated by Joshi and Pohlner it is believed that the cause of the arrhythmias’ is atrial dilatation and structural disorientation of the myocardial fibers and conduction system. This can be explained by the fact that when the RAA is removed normal sinus rhythm usually returns . Forbes et al. reported a case in which the patient presented with severe and refractory arrhythmia despite of normal atrial tissue found during histological exam . After the surgery our patient regained normal sinus rhythm.
There is no unified opinion on how to treat patients with RAA. There are two main approaches: conservative and surgical. Conservative approach is suggested to patients, who are asymptomatic and who are diagnosed with mild to moderate atrial dilatation. As suggested by Harder et al. those patients should receive low-dose aspirin thromboprophylaxis and they should be followed up regularly. They also emphasize that patients with severe dilatation of the atrium and symptomatic patients should be treated surgically . The main indications for surgery are: atrial arrhythmia, intraatrial thrombus formation, major atrial dilatation, and compression of other heart chambers [1, 6, 7, 14]. Binder et al. state that surgical resection of right atrial aneurysm has a low mortality risk . It is believed that early correction prevents further dilatation of the RA and complications associated with the presence of the RAA (such as heart failure, supraventricular arrhythmias, thrombus formation, and pulmonary or paradox embolism) [1–5, 10, 11, 15, 16]. As there are no studies that compare the two approaches we believe that each patient should be approached individually. In our case the patient was symptomatic and in critical condition. In this situation a decision to perform surgery was made as recommended by literature.
Majority of reports about this defect favours using CPB during aneurysmectomy, but Joshi and Pohlner suggest that it is safe to perform off-pump aneurysmectomy using delicate vascular clamps [2–4, 9, 12, 15, 16]. In our case we had to use CPB, because of three reasons. Firstly, the aneurysm was distended, its wall was paper-thin and risk of rupture was considered high. Secondly, open heart procedure was needed in order to close the PFO. Lastly, an unexpected finding of the protruding RCA also favoured an open heart procedure.