Classification of longitudinal strain curves measured by speckle-tracking echocardiography in normal and pathological myocardial segments

Abstract

Abstract Background Two-dimensional speckle-tracking echocardiography (2D-STE) provides a quantitative tool to evaluate LV function at the regional level. The purpose of this study was to classify the types of regional longitudinal strain curves (LSC). Moreover, we propose a novel longitudinal strain curve index (LSCI) which we compared to the wall motion score index (WMSI). Methods We enrolled 100 healthy volunteers and 50 patients with prior myocardial infarction (MI). Each LSC was classified considering the positive peak (peak P), peak maximum strain (PMS), and time to maximum peak strain (TPMS) as follows: Type 1 (Peak P<6%, PMS>6%, TPMS before aortic valve closure [AVC]); Type 2 (Peak P<6%, PMS≥6%, TPMS after AVC); Type 3 (Peak P≥6%, PMS≥6%, TPMS before AVC); Type 4 (Peak P≥6%, PMS≥6%, TPMS after AVC); Type 5 (Peak P<6%, PMS≥6%, TPMS first third of systole); Type 6 (Peak P<6%, PMS<6%); and Type 7 (Peak P≥6%, PMS<6%). The longitudinal curve score index (LCSI) was obtained (sum of LSC type/18 segments). Results A total of seven types of LSC were identified. In the healthy subjects, LSC Type 1 (T1) and Type 2 (T2) were the most frequent. Type 3 (T3) and Type 4 (T4) were found in insignificant percentages while Type 5 (T5), Type 6 (T6), and Type 7 (T7) were not identified. When analyzed for the entire population, LSCI correlated strongly with WMSI (r=0.83, p<0.01). Conclusions Analysis of LSC may provide a substantial support to visual assessment of regional LV function and the LCSI represents an index that is highly reproducible, independent of the examiner’s experience.