Characterisation of Left Ventricular Shape Change as Defined by Sphericity Index in Patients with Acute Phase Takotsubo Cardiomyopathy and Anterior STEMI Patients

Abstract

Background: Left ventricle (LV) shape changes have been proposed to be predictive of cardiovascular outcomes. Extreme sphericity has been shown to be a strong predictor of heart failure and atrial fibrillation. Sphericity index (SI) is a measure that may be used to quantify LV shape changes. The aim of our study was to characterise LV shape changes using SI between patients with acute phase Takotsubo's cardiomyopathy (TTC) and acute anterior transmural infarction (AMI). Methods: Consecutive TTC (n = 49) and AMI (n = 51) patients with a comprehensive transthoracic echocardiogram during index admission were examined. Standard measures of LV size and systolic function were compared between groups. Mean SI was calculated as an average of the ratio of the short-axis length to the long-axis length in 4- and 2-chamber apical views in both end-diastole (ED) and end-systole (ES). Both groups were also compared to healthy controls (n = 50) and dilated cardiomyopathy (DCM) controls (n = 39). Results: TTC and AMI patients had significantly worse LVEF and greater SI compared to normal controls suggesting LV shape change but not to the degree of DCM patients. Interestingly, there was no significant difference in LVEF between TTC (51 ± 12%) and AMI (53 ± 13%) [p = 0.52] but there was a significant difference in mean SI for TTC (0.60 ± 0.06) vs AMI (0.52 ± 0.07) [p < 0.0005] reflecting a more spherical shaped ventricle in the TTC group. Conclusions: Our results demonstrate differences in LV shape between different cardiac pathologies. Characterisation of these LV geometric changes may provide mechanistic insights into these underlying cardiac pathologies and guide management strategies.