Left Ventricular Sphericity Index is a reproducible bedside echocardiographic measure of geometric change between acute phase Takotsubo's syndrome and acute anterior myocardial infarction

Background: Left ventricular sphericity index (LVSI) is a simple, quick and reproducible measure to evaluate LV geometric changes. The aim of our study was to evaluate the utility of LVSI as a rapid discrimination tool in two disease processes; Takotsubo’s Syndrome (TS) and Anterior Myocardial Infarction (AMI), in the absence of significant left ventricular systolic dysfunction. Methods: Consecutive patients with acute phase TS admitted to our institution (Jan 2013 - Dec 2018) were evaluated (n=66). Patients with a comprehensive two-dimensional transthoracic echocardiogram were included in primary analysis (n=50) and age-matched with a cohort of patients with acute anterior AMI (n=50). Appraisal of demographic, clinical and echocardiographic parameters of patients was undertaken. Biplane LVSI was calculated as an average of the short- and long-axis length in the 4- and 2-chamber apical views. Results: A total of 50 TS patients (64.3±13.7 years, 18% men) were matched with 50 AMI (62.10±12.84 years, 74% men) patients. There was no significant difference in baseline cardiovascular risk factors other than diabetes mellitus (AMI 34% vs TS 17%, p = 0.034). There was also no difference in LV mass (p=0.10) or LVEF (p=0.52) between the two groups. Interestingly, there was a significant difference in mean LVSI between TS (0.60±0.06) vs AMI (0.52±0.07) (p<0.01) reflecting a more spherical shaped left ventricle in the acute TS group. Conclusions: LVSI is reflective of geometric changes in the left ventricle and may be helpful as a rapid and reproducible diagnostic tool in differentiating between TS and AMI in the acute phase.