Is Longitudinal Strain Associated with Left Ventricular Remodeling in Patients with Acute Myocardial Infarction?

Abstract

To the Editor: Recently, Park et al documented a strong association between longitudinal strain (LS) assessed by echocardiography and left ventricular (LV) remodeling in 50 patients with acute myocardial infarction (AMI). The investigators, using both conventional Doppler tissue imaging and speckle tracking imaging, showed that patients who developed severe left ventricular remodeling, in a variable time setting after AMI (range 3-47 months), had significantly lower baseline LS and that this variable was a strong independent predictor of the remodeling process. Despite the appealing objective of the study, we would like to comment on 2 notable limitations. First, baseline left ventricular systolic function, as determined by LV ejection fraction and wall motion score index, was significantly different between the 2 groups studied. Ideally, LS should be evaluated as an independent risk factor for future remodeling between 2 groups of patients with relatively comparable LV systolic function. Second and most important is the different time period during which LV remodeling was assessed by echocardiography (with a range of 3-47 months) after the index infarction. Of interest is the fact that the investigators did not include in their multivariable model analysis novel indices of LV diastolic filling, such as E/e= and E/Vp, that have been recently shown as accurate prognostic markers of LV remodeling in the setting of reperfused AMI. We have recently commented on an article concerning postinfarct LV remodeling in the modern clinical era and presented our own experience in a population of patients with early effective reperfusion. We proposed that E/Vp ratio and brain natriuretic peptide levels are the strongest predictors of LV remodeling. We used conventional Doppler tissue imaging to assess LS in the anterior wall and found no significant association between LS and the net change of LV systolic volume index in a 6-month period after a reperfused anterior AMI. In contrast, we observed that patients in the remodeling group had less evidence of post-systolic shortening in the strain curve in the risk area of the anterior wall (11% vs 39%, P .03). The presence of post-systolic shortening that may reflect stunned myocardial tissue remains controversial for the time being and awaits further investigation. We believe that larger studies are needed to evaluate LS as an independent predictor of LV remodeling. Christodoulos E. Papadopoulos, MD Georgios A. Giannakoulas, MD Theodoros D. Karamitsos, MD Haralambos I. Karvounis, MD Ioannis Stiliadis, MD Georgios E. Parharidis, MD First Cardiology Department AHEPA University Hospital Aristotle University of Thessaloniki Greece