Background Postsystolic shortening (PSS) has been proposed as a marker of myocardial dysfunction.Strain rateimaging (SRI) is a novel ultrasonic technique,allowing reliable and noninvasive measurement of myocardial deformation.The purpose of this study was to investigate the characteristics of myocardial longitudinal PSS by SRI in ischemic andinfarct myocardium in patients with coronary artery disease,and to explore its clinical applicability.Methods Eleven patients with angina pectoris,21 patients with myocardial infarction and 20 healthy subjects wereincluded in the study.Apical four-,three-and two-chamber views were displayed;and septal,lateral,anteroseptal,posterior,anterior and inferior walls of the left ventricle were scanned,respectively.PSS strain (ε_(pss)),the ratio of ε_(pss)andsystolic strain (ε_(pss)/ε_(sys)),the ratio of ε_(pss) and maximum strain (ε_(pss)/ε_(max)) and the duration of PSS (T_(pss)) in ischemic,infarctand normal myocardium were analyzed.Results PSS was found more frequent in the ischemic and infarct segments compared with the normal segments (39%vs 22% and 56% vs 22%,respectively;both P<0.01).It was even more frequent in the infarct segments than in theischemic segments (56% vs 39%,P<0.01).The absolute magnitude of ε_(pss),ε_(pss)/ε_(sys),ε_(pss)/ε_(max)were significantly larger andTpss significantly longer in the ischemic and infarct segments compared with that in the normal myocardium (P<0.01).ε_(pss)/ε_(sys),ε_(pss)/ε_(max) were even larger and T_(pss) even longer in the infarct than in the ischemic segments (P<0.01).Conclusions PSS is a common and important feature of the ischemic and infarct myocardium.ε_(pss),ε_(pss)/ε_(sys),ε_(pss)/ε_(max)and mpss as measured by SRI may be promising markers for the quantitative assessment of regional myocardialdysfunction in patients with coronary artery disease.ε_(pss)/ε_(sys),ε_(pss)/ε_(max)and Tpss may be helpful in differentiating infarct fromischemic myocardium. Background Postsystolic shortening (PSS) has been proposed as a marker of myocardial dysfunction. Strain rateimaging (SRI) is a novel ultrasonic technique, allowing reliable and noninvasive measurement of myocardial deformation. The purpose of this study was to investigate the characteristics of myocardial longitudinal PSS by SRI in ischemic and infarct myocardium in patients with coronary artery disease, and to explore its clinical applicability. Methods Eleven patients with angina pectoris, 21 patients with myocardial infarction and 20 healthy subjects wereincluded in the study. Acicular four-, three- and two- chamber views were displayed; and septal, lateral, anteroseptal, posterior, anterior and inferior walls of the left ventricle were scanned, respectively. PSS strain (ε_ (pss)), the ratio of ε_ (pss) and systolic strain (ε_ (pss) PSS (T_ (pss)) in ischemic, infarct and normal myocardium were analyzed. Results PSS wa s found more frequent in the ischemic and infarct segments compared with the normal segments (39% vs 22% and 56% vs 22%, respectively; both P <0.01) .It was even more frequent in the infarct segments than in the ischemic segments 56% vs 39%, P <0.01). The absolute magnitude of ε pss, ε pss / ε sys, ε pss / ε max were significantly larger and T pss significantly longer in the ischemic and infarct segments compared with that in the normal myocardium (P <0.01) .ε_ (pss) / ε_ (sys), ε_ (pss) / ε_ (max) were even larger and T_ (pss) even longer in the infarct than in the ischemic segments (P <0.01) .Conclusions PSS is a common and important feature of the ischemic and infarct myocardium. ε - (pss), ε pss / ε sys, ε pss / ε max and mpss as measured by SRI may be promising markers for the quantitative assessment of regional myocardial dysfunction in patients with coronary artery disease. ε_ (pss) / ε_ (sys), ε_ (pss) / ε_ (max) and Tpss may be helpful in differentiating infarct from ischemic myocardium.