1351400 - Large left ventricular pseudoaneurysm presenting with fast atrial fibrillation

A 64-year-old woman with previous history of rheumatoid arthritis and mild chronic obstructive pulmonary disease presented to our hospital with shortness of breath and palpitations. Her electrocardiogram showed atrial fibrillation with fast ventricular response and T-wave inversion in leads I, aVL, V4-V6. A computed tomography scan of her chest revealed cardiomegaly with no evidence of pulmonary embolism. She was treated with antibiotics for chest infection and was referred for a transthoracic echocardiogram given the evidence of cardiomegaly and new atrial fibrillation.

Diagnostic Techniques and Their Most Important Findings:

The echocardiogram showed a large aneurysm in the inferior left ventricular (LV) wall (Figure 1, panels A and B), with possible fistulous communication to the right atrium. She was subsequently referred to our department for a cardiac magnetic resonance imaging (CMR) scan to further characterise the LV aneurysm. The CMR scan revealed a large pseudo-aneurysm of the basal-mid inferior LV wall, occupying almost one quarter of the LV circumference, due to a large transmural myocardial infarction in the basal-mid inferoseptal, inferior and inferolateral walls. The pseudo-aneurysm was contained by pericardial tissue, with no evidence of thrombus and no shunt to the right atrium (Figure 2, panels A-D). The LV was moderately dilated, with severely impaired systolic function (ejection fraction 28%). Cardiac catheterization showed occlusion of the mid-right coronary artery, with non-obstructive plaque disease in the left coronary circulation, and the large LV pseudoaneurysm in the inferior LV wall (Figure 1, panels C and D). The patient underwent successful aneurysmectomy and LV reconstruction with the Dor procedure (Figure 2, panels E and F).

Learning Points from this Case:

LV pseudoaneurysms are due to myocardial wall rupture, which is contained by overlying pericardium, thrombus, and/or scar tissue¹, in contrast to true aneurysms which result from scar formation and thinning of the myocardial wall². LV pseudoaneurysms are most commonly due to myocardial infarction, but may also occur after cardiac surgery, endovascular interventions or trauma³. They are rare in the current era of timely revascularisation, but timely diagnosis and treatment are essential due to a high risk of rupture and death⁴.

Differentiation between LV pseudoaneurysms and true aneurysms can be challenging based on conventional imaging with echocardiography or cardiac catheterization. CMR imaging can reliably differentiate pseudoaneurysms from true aneurysms, assess for the presence of LV thrombus and aid in surgical treatment planning.