Case Report: A 22-year-old male presented with the complaint of pain on the left side of chest on deep inspiration for two months and dyspnea on exertion for one month. There was no history of breathlessness or trauma to the chest. On examination, vital parameters were normal. Cardiovascular examination revealed a loud first heart sound and audible fourth heart sound; the second heart sound was normal.

RADIOLOGICAL FINDINGS:

Frontal and lateral chest radiographs (Fig 1, 2) showed an approximately 5 cm x 4 cm well defined soft tissue density mass lesion in the region of left hilum, obscuring the left heart border. The lesion showed a discontinuous rim of calcification. The left hilum was seen through the lesion suggesting that it was separate from the left hilum. The lung fields were normal.

Plain and contrast enhanced CT scan of the chest showed an approximately 6 cm x 5 cm x 5 cm sized peripherally calcified lesion in relation to the anterosuperior wall of the left ventricle. There was intense enhancement on post contrast scan. (Figs 3,4,5)

Cardiac MRI was done next. This revealed an approximately 6 cm x 5 cm x 5 cm sized pseudoaneurysm arising from the anterosuperior wall of the left ventricle. This sac filled during systole and a jet was seen extending within the aneurysm. The lesion was in close proximity to the mitral valve but seen separate from it. The left main pulmonary artery and left main bronchus were displaced superiorly due its mass effect. Post contrast dynamic angiography shows no clot or thrombus within ventricles. (Figs 6-12)

2D echocardiography also reveled similar findings.

A diagnosis of a left ventricular pseudoaneurysm was made.

DISCUSSION:

Left ventricular aneurysms are large thin walled fibrous sacs bulging from the lumen of the left ventricular cavity and also from the external surface of the heart and are usually clearly demarcated from the normal myocardium. A pseudoaneurysm is a rupture of the myocardium that is contained by pericardial adhesions.

AETIOLOGY:
Over 95% of true left ventricular aneurysms result from coronary artery disease and myocardial infarction. True left ventricular aneurysms also may result from trauma, Chagas' disease or sarcoidosis. A very small number of congenital left ventricular aneurysms also have been reported and have been termed diverticula of the left ventricle.

False aneurysms of the left ventricle result most commonly from contained rupture of the ventricle 5 to 10 days after myocardial infarction and often occur after left circumflex coronary arterial occlusion. False aneurysms of the left ventricle also may result from submitral rupture of the ventricular wall after mitral valve replacement. Left ventricular pseudoaneurysm may also result from septic pericarditis or any prior operation on the left ventricle, aortic or mitral annulus.

Location:

One of the most easily documented features proposed for distinguishing true aneurysms from pseudoaneurysms is location. Plain chest radiography often reveals pseudoaneurysm, particularly when there is a discrete bulge in the cardiac shadow in an atypical location for ordinary cardiomegaly, such as posteriorly. It has been suggested that an inferior or posterior location is suggestive of pseudoaneurysm rather than a true aneurysm.

Symptoms and Examination Findings:

Angina is the most frequent symptom in most series of patients operated upon for left ventricular aneurysm. Dyspnea is the second most common symptom of ventricular aneurysm and often develops when 20% or more of the ventricular wall is infarcted. Either atrial or ventricular arrhythmias may produce palpitations, syncope or sudden death or aggravate angina and dyspnea in up to one third of patients.

Symptoms of pseudoaneurysm include recurrent chest pain which may be associated with symptoms of hypotension. Signs of a pseudoaneurysm include decreased heart sounds, a pericardial friction rub, elevation of both left- and right-sided filling pressures, and sinus bradycardia or junctional rhythm. When the pseudoaneurysm is large, and it may produce an apical impulse. Mechanical interference of the mass on ventricular filling may result in a third heart sound. A pansystolic or to-and-fro murmur may be produced by flow across the mouth of the pseudoaneurysm. The ECG often shows persistent ST segment elevation in the area of the infarct. Unfortunately, all of these signs and symptoms are also characteristic of true aneurysms.

Imaging Characteristics:

Contrast Ventriculography

Left ventriculography is the gold standard for diagnosis of left ventricular aneurysm. The diagnosis is made by demonstrating a large, discrete area of dyskinesia (or akinesia), generally in the anteroseptal-apical walls. Occasionally, left ventriculography also may demonstrate a mural thrombus. Outward motion is termed dyskinetic, and the remaining aneurysmal segments are termed akinetic. The characteristic feature of pseudoaneurysms is a narrow neck connecting the ventricle to the pseudoaneurysm cavity.

Radionuclide ventriculography may be used for the diagnosis

Magnetic Resonance Imaging:
The advantages of MRI are its high spatial resolution and ability to image the entire heart. Thus, it is highly accurate in determining the size and location of the pseudoaneurysm. It is also capable of distinguishing between pericardium, thrombus, and myocardium and the potential to visualize disruption of the epicardial fat layer by the pseudoaneurysm.

Echocardiography:
Two-dimensional echocardiography is also a sensitive and specific means of diagnosing left ventricular aneurysm .Mural thrombus and mitral valve regurgitation are detected most readily by echocardiography. Echocardiography is also useful for distinguishing pseudoaneurysm from true aneurysm by demonstrating a defect in the true ventricular wall.

Trans Esophageal Echocardiography (TEE) is the modality most studied with respect to distinguishing ventricular aneurysms from pseudoaneurysms. The nature of flow within a pseudoaneurysm has been used to distinguish it from true aneurysm based on results with echocardiographic Doppler techniques. The presence of turbulent flow by pulsed Doppler at the neck of a cavity or within the cavity itself suggests pseudoaneurysm.

Natural History:
Frank rupture of chronic left ventricular pseudoaneurysms is less common than one might expect. Rupture of left ventricular pseudoaneurysms may be most likely in the acute phase or in large-sized pseudoaneurysms. Left ventricular pseudoaneurysms tend to behave similar to true aneurysms in that they may present a volume load on the left ventricle or may be a source of embolization or endocarditis. Left ventricular pseudoaneurysms after prior cardiac surgery have also been reported to compress adjacent structures such as the pulmonary artery or esophagus.

Treatment: Surgery is the treatment of choice for pseudoaneurysms due their propensity to rupture while true aneurysms can be managed medically in low risk patients.