Myocardial deformation and rotational mechanics in revascularized single vessel disease patients 2 years after ST-elevation myocardial infarction.

OBJECTIVE: We sought to characterize the left ventricular strains and rotational mechanics in the infarct-related and remote regions of dilated heart following an ST-elevation myocardial infarction (STEMI) to understand the adaptive changes in global left ventricular function that develop several months after percutaneous coronary revascularization.

METHODS: Forty-six patients with STEMI (66.6 ± 11 years, 29 men) 2 years after coronary revascularization were enrolled. Longitudinal, circumferential, radial and rotational mechanics of the left ventricle were evaluated by speckle tracking echocardiography in 39 (84.8%) of them, after excluding seven patients with multivessel coronary disease. Forty-one asymptomatic volunteers without a history of coronary artery disease (65 ± 9 years, 23 men) served as controls.

RESULTS: There was no difference, between groups, regarding the prevalence of cardiovascular risk factors, whereas patients had significantly reduced left ventricular strains (P<0.001), rotations (P<0.001), twist (P<0.001), torsion (P<0.001) and untwisting rates (P<0001) in comparison with controls. Furthermore, reduction in regional strains was observed both in infarct and remote regions of the left ventricle and correlated with the changes in ejection fraction. On logistic regression analysis, only global circumferential strain was independently related (odds ratio 4.28; 95% confidence interval 1.11-16.4; P=0.034) with left ventricular dilation, defined as an indexed end-diastolic left ventricular volume more than 75 ml/m.

CONCLUSION: Reduction in regional strains and rotational mechanics are detectable in both the infarct-related and remote regions of dilated left ventricle. Attenuation of global circumferential strain, rather than isolated changes in the mechanics of the infarct region might contribute to determine the extent of left ventricular dilation, independent of the presence of multiple risk factors for left ventricular dysfunction. These findings might have important clinical implications regarding novel therapeutic approaches for counteracting left ventricular remodeling.