Variations in regional strain under different afterload conditions may help to identify ischemic myocardium

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Acute coronary syndromes are a major health problem worldwide. The Speckle Tracking Imaging has been proposed as adjunctive for diagnosis and prognosis purposes in the context of NSTE-ACS. Purpose We sought to determine the regional myocardial strain in ischemic versus non-ischemic segments in subjects with NSTE-ACS, before and during acute pressure overload. Methods Data from 2D-echocardiography were obtained from 21 patients (mean age, 50 ± 10 years) undergoing cinecoronariography for NSTE-ACS indications. A blinded observer performed an offline analysis to obtain the Systolic Positive Peak (P), Systolic Peak Strain (S), Peak Strain (G) and Time to Peak Strain (TTP) of each segment acquired before and during pressure overload-induced by left hand-grip (42± 8 Kg) combined with simultaneous pneumatic constriction of the right arm and both lower limbs. Moreover, LVEF and GLS were also calculated. A second blinded observer labelled the ischemic regions according to AHA-16 Bull’s eye using data from cinecoronariography. Results The handgrip manuever caused mild reductions in the median LVEF (56 %; IQR 48 -58% vs 54%; IQR 51-56%) as well as the median GLS (-17%; IQR-19%-15% vs -16%; IQR -19-15%). For the analysis of regional myocardial function, we obtained 360 segments (29% labelled as ischemic) with optimal tracking quality. Mean regional strain changes during pressure overload were significantly different in ischemic vs non-ischemic segments for Peak S ( 1,07% x -0.5%; p-value <0,01) and Peak G (0.85% x -0.65%; p-value < 0.01)(Table). Notably, however, we found marked increases in the systolic deformation, restricted to the apical ischemic segments during pressure overload (Figure). Conclusions Our data point to a distinct increase in the systolic deformation of the apical segments in contrast to the overall reductions in the GLS and EF in the ischemic left ventricle. Non- Ischemic segments N = 256 Ischemic segments N = 104 Baseline Handgrip Variation (%) Baseline Handgrip Variation (%) p-value* Peak P 0.33(0.57) 0.36(0.7) 0.03(0.7) 0.50(0.7) 0.57(0.8) 0.07(0.8) 0.32 Peak S -17.9(4.4) -16.8(5.3) 1.07(4.1) -16.6 (5.2) -17.2(5.6) -0.5(4.8) 0.0006 Peak G -18.5 (4.2) -17.68 (4.6) 0.85 (3.7) -17.3 (4.5) -18 (4.6) -0.65(4.2) 0.0005 TTP 377(62) 384(66) 6.5(52) 387(65_ 388(62) 1.15(46) 0.17 * t- test comparing the variations baseline-handgrip between the two groups (ischemic versus non-ischemic. Peak P= positive systolic peak; Peak S= systolic peak; Peak G= peak strain; TTP= time to peak Abstract Figure