Background: The mechanics of the complex left ventricular (LV) myocardial fiber architecture may accurately be assessed by speckle tracking echocardiography (STE). The role of STE to assess LV mechanical dysfunction in the setting of ST segment elevation myocardial infarction (AMI) is still poorly studied.
Patients and methods: 29 consecutive patients (55 +/- 13 years) presenting with AMI underwent STE within 72 hours of admission. Reperfusion was achieved with thrombolysis in 15 patients and with primary percutaneous coronary intervention in 14. LV rotational and torsion data were registered during peak systole. Standard Doppler data included LV ejection fraction (EF), mitral inflow deceleration time (DT), and conventional E/A ratio. E/E' ratio (mitral inflow E velocity/tissue Doppler E velocity) was calculated as a marker of LV filling pressure. Twelve subjects with clinically indicated but negative dobutamine stress echocardiogram served as Controls.
Results: Peak systolic torsion was not only significantly lower in AMI compared with Controls (13.3 +/- 7.6 vs. 21.8 +/- 6.1; P < 0.01), it was also lower in subjects with LVEF <40% (5.0 +/- 2.9) compared with those who had LVEF >40% (10.6 +/- 6.6; P < 0.02). Torsion had a modest but significantly positive linear relation (R = 0.6; P < 0.05) with DT, not with E/E' or LVEF.
Conclusion: LV systolic torsion is decreased in AMI and more markedly decreased in patients with LVEF <40%. The most significant linear relationship between DT and torsion may possibly indicate that the LV mechanical dysfunction is also associated with altered filling dynamics.