Validity of the left ventricular sphericity index in apical and basal aneurysms

Left ventricular aneurysm (LVA) correlates with changes in ventricular geometry related to the size and shape of the left ventricle (LV). On echocardiography it presents as global changes in the ventricle with reduced systolic function (ejection fraction - EF). Abnormal remodeling geometry of the ventricle leads to a more spherical shape and the manifestation of the spherity index (SI) as a parameter of abnormal geometric change (SI is the ratio of the short (S) to the long (L) axis of the heart measured from the apical four-chamber view). In healthy individuals and in ischemic dilated cardiomyopathy SI remains constant due to proportional enlargement of S and L.

The aim of this study was to evaluate the value of SI in the presence of apical left ventricular aneurysm (A-LVA) and basal aneurysm (B-LVA) using echocardiography, to determine the parameters that can influence SI, and their significance in daily clinical practice.

The clinical study included 54 patients with post-infarction LVA (36 men, 18 women). The localization of the LVA was determined by echocardiography. A-LVA was formed near the apex of the LV, while B-LVA was in the basal segments of the LV walls. SI was determined in systole and diastole in the entire population and stratified among patients with A-LVA and B-LVA. LV EF was determined by Simpson's method.

Study included 41 patients with A-LVA and 13 with B-LVA. The average SI value in diastole was 0.55 and in systole 0.47. Patients with A-LVA had an average SI value in diastole of 0.51 and in systole 0.44. Significantly higher SI values were found in the presence of B-LVA, with diastolic SI at 0.65 and systolic SI at 0.57 compared to A-LVA. The reason is that the long axis (L) values of the heart in both diastole and systole are lower in B-LVA compared to A-LVA.

LV EF in patients with A-LVA was 23.95%, and in B-LVA, it was 30.85%, with no significant difference. The difference in absolute values is due to apical aneurysms being larger compared to basal aneurysms, thus more significantly reducing the percentage of functional myocardium.

The results indicate that it is important to differentiate A-LVA and B-LVA by determining SI using echocardiography. SI is higher in B-LVA due to the reduction of the long axis (L). Surgical reconstruction of the left ventricle always addresses the reduction in length (L) compared to the reduction in width (S). Therefore, in surgical reshaping of the LV for B-LVA, it is crucial to maximally preserve the long axis (L) to maintain a more physiological shape.