Identification of viable myocardium in acute anterior infarction using duration of systolic lengthening by tissue Doppler strain: a preliminary study

Abstract

Background: The aim of this study was to investigate whether strain Doppler echocardiography before reperfusion therapy could quantify ischemic dysfunction and predict viable myocardium in acute myocardial infarction as determined by magnetic resonance imaging.

Methods: Twenty-six patients (mean age, 60 ± 12 years; seven women) with acute myocardial infarctions who underwent acute percutaneous coronary intervention were examined using strain Doppler echocardiography immediately before the procedure. Percutaneous coronary intervention was performed 296 ± 122 min after the onset of pain. Peak left ventricular systolic longitudinal strain and the duration of systolic lengthening were analyzed. Magnetic resonance imaging was performed 11 ± 5 months after therapy. Scarring exceeding 50% of the segment area was considered nonviable.

Results: Peak systolic strain fell gradually (becoming less negative) from normal segments to segments with transmural infarction (P < .0001), and the duration of systolic lengthening increased (P < .0001). Myocardial scarring was closely correlated with peak systolic strain (R = 0.76, P < .00001) and the duration of systolic lengthening (R = 0.88, P < .00001). There was a significant correlation between the degree of scarring and time to percutaneous coronary intervention (R = 0.40, P = .045). In segments with systolic lengthening, the improvement in strain after remodeling was significantly higher (5.5 ± 5.1%) than in segments with duration of systolic lengthening > 67% of systole (2.2 ± 3.7%) (P < .001). Receiver operating characteristic curve analyses showed that duration of systolic lengthening > 67.3% could identify nonviable myocardium (sensitivity, 90%; specificity, 94%).

Conclusions: In patients with acute myocardial infarctions in the anterior wall, strain measurements can identify myocardium with nontransmural scarring. The duration of systolic lengthening is a novel, easily implemented variable that may identify ischemic but viable myocardium. Myocardial infarctions in other left ventricular regions should be investigated in future studies.