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Clinical profile | Discussion

CLINICAL PROFILE:

A 32-year-old lady presented with a lump in the right breast. She was a known case of rheumatic heart disease (mitral regurgitation with mitral stenosis] who had undergone ring annuloplasty 15 years ago, followed by mitral valve replacement three years ago and has been asymptomatic since.

General physical examination was normal.

On cardio-vascular system examination, a click & a mid diastolic murmur were heard in the mitral area.

On respiratory system examination, a dull note & absent breath sounds over the right mid and lower chest were elicited A 3 X 3 cms, firm mass was palpated in the right breast with retraction of the nipple. No lymph nodes were palpable.

A frontal chest radiograph was advised which showed cardiomegaly and obliteration of the right costophrenic angle (Fig. 1) .

Fig.1

A pleural effusion was suspected and tapping was attempted. Bright red blood was apirated; this clotted on standing.

A lateral chest radiograph and chest ultrasound were performed. It showed a large cystic mass with color signals and swirling motion within it suggestive of vascular lesion. (Fig2, 3,4,5,6)

Fig.2	Fig.3
Fig.4	Fig.5
Fig.6

2D was performed which showed massively dilated left atrium with prosthetic mitral valve. Mitral valve area is 1.4 sq cms. LV function was depressed with ejection fraction being 42%.

A CT scan was performed..(Fig. 7,8,9,10,)

Fig.7	Fig.8
Fig.9	Fig.10

Axial plain and contrast scans with delayed cuts showed a massively dilated left atrium measuring 18.3 X 12 cms in size, displacing the right heart chambers anteriorly and compressing them. A hypodense lesion was seen along the postero-lateral wall of the left atrium suggestive of thrombus. A mitral valve prosthesis was seen in situ. The thrombus was probably the result of tapping. Finally, the diagnosis of giant left atrial Aneurysm in an operated case of rheumatic heart disease was arrived at.

The patient was digitalized and put on anti-coagulants and hematinics.

The lump in the breast was diagnosed as ductular carcinoma for which a modified radical mastectomy was performed. Intervention for the atrial aneurysm is planned after the patient has recovered from the above surgery.

DISCUSSION:

Aneurysm of the left atrium is rare. They can be congenital or acquired. Congenital aneurysms are the commonest. Whereas a true congenital aneurysm presents as an isolated pathology, inflammatory or degenerative processes involving the endocardium are associated with the acquired type. A pericardial defect may be associated.

In our case, the left atrial aneurysm has clearly been secondary to rheumatic heart disease involving the mitral orifice. Moreover, the patient has been operated on for ring annuloplasty as well as mitral valve replacement sometime in the past.

Historically, whether or not a pericardial defect is associated was ascertained by a diagnostic left sided pneumothorax with air entering the pericardial cavity, although a negative finding does not rule out the presence of a defect.

Mitral valvular diseases, like regurgitation and stenosis in later stages, cause backpressure changes on the left atrium, which eventually leads to its gradual dilatation.

When there is mild dilatation of the left atrium, it pushes the left atrial appendage so that the latter contributes to the left heart border. In such a case, the left heart border appears straightened.

Further enlargement leads to splaying of the carina. The normal carinal angle is about 55 degrees.

With even further dilatation, the left atrium will be seen to the right of the spine and at this point, we see a double atrial shadow. If the left atrium enlarges still further like in our case, it occupies most of the right hemithorax.

A giant left atrial aneurysm is defined as one which measures >65mm on echocardiogram.

An aneurysm >160mm as in our case has never been reported.

Complications that can occur are:

Compression over the esophagus, pulmonary veins, trachea, left main bronchus, lung, inferior vena cava, left recurrent laryngeal nerve & thoracic vertebrae.

Cardiac effects: Paradoxical movement of left ventricle, atrial fibrillation & thromboembolism.

Cardiac surgery [aneurysmectomy] is advisable if the patient develops significant symptoms or if there is a progressive increase in atrial size. Extensive resection is carried out with LA diameter of more than 80 mm. Limited resection is carried out with LA diameter of less than 80mm.