Quantification of regional contractile function after infarction: Strain analysis superior to wall thickening analysis in discriminating infarct fromremote myocardium

OBJECTIVES Using two-dimensional wall thickening (WT) (expressed as percent age) and strain analysis, regional contractile myocardial function was quan tified and compared in 13 control subjects and 13 patients with a first myo cardial infarction (MI). The finding in the patient group were related to g lobal ventricular function and infarct size. BACKGROUND In patients with coronary artery disease, regions with dysfuncti onal myocardium cannot be differentiated easily from regions with normal fu nction by planar WT analysis. Physiologic factors, in combination with limi tations of conventional imaging techniques, affect the calculation of WT. Q uantitative assessment of contractile function by magnetic resonance (MR) t issue tagging and strain analysis may be less affected by these factors. METHODS Two-dimensional regional WT and strain were calculated in three sho rt-axis MR cine and ragged images, respectively. Left ventricular volumes a nd ejection fraction (EF) were obtained from a series of contiguous short-a xis cine images. RESULTS In patients with infarct-related ventricles, WT and strain analysis both revealed reduced myocardial function, as compared with control subjec ts (p < 0.005 and p < 0.001, respectively). However, WT analysis yielded no significant regional differences in function between infarct-related and r emote myocardium (p = 0.064), whereas strain analysis did (p < 0.005). For detecting dysfunctional myocardium of electrocardiographically and angiogra phically defined infarct areas, WT analysis had a sensitivity of 69% and a specificity of 92%, whereas strain analysis demonstrated a sensitivity of 9 2% and a specificity of 99%. The EF correlated with WT (r = 0.76, p < 0.005 ) and strain (r = 0.89, p < 0.001). CONCLUISONS Two-dimensional strain analysis is more accurate than planar WT analysis in discriminating dysfunctional from functional myocardium, and i t provides a strong correlation between regional myocardial and global vent ricular function. (J Am Coil Cardiol 2001;37: 808-17) (C) 2001 by the Ameri can College of Cardiology.