Objective To quantitatively evaluate the associations of infarct size, regional myocardial function examined by cardiac magnetic resonance feature tracking (CMR-FT) strain analysis with infarct location in patients with ST-segment elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention.Methods Cardiac magnetic resonance images were retrospectively analyzed in 95 consecutive STEMI patients with successful reperfusion. The patients were divided into the anterior wall myocardial infarction (AWMI) and nonanterior wall myocardial infarction (NAWMI) groups. Infarct characteristics were assessed by late gadolinium enhancement. Global and regional strains and associated strain rates in the radial, circumferential and longitudinal directions were assessed by CMR-FT based on standard cine images. The associations of infarct size, regional myocardial function examined by CMR-FT strain analysis with infarct location in STEMI patients were evaluated by the Spearman or Pearsonmethod. Results There were 44 patients in the AWMI group and 51 in the NAWMI group. The extent of left ventricular enhanced mass was significantly larger in patients with AWMI compared with the NAWMI group (24.47±11.89, 21.06±12.08 %LV; t=3.928, P = 0.008). In infarct zone analysis, strains in the radial, circumferential and longitudinal directions were remarkably declined in the AWMI group compared with the NAWMI group (z=-20.873, -20.918, -10.357, all P < 0.001). The volume (end-systolic volume index), total enhanced mass and extent of enhanced mass of the left ventricular were correlated best with infarct zone strain in the AWMI group (all P < 0.001). Conclusion In STEMI patients treated by percutaneous coronary intervention, myocardial damage is more extensive and regional myocardial function in the infarct zone is lower in the AWMI group compared with the NAWMI group.
Keywords: acute myocardial infarction; cardiac magnetic resonance; left ventricular; myocardial strain; tissue tracking.