Objective: Regional left ventricular (LV) function could be detected by measuring peak-systolic strain by speckle tracking imaging (STI). We evaluated the value of STI combined with adenosine stress echocardiography on assessing myocardial viability in patients with myocardial infarction (MI).
Methods: Two dimensional echocardiography was performed at rest and after adenosine stress echocardiography (infused at 140 µg×kg(-1)×min(-1) over a period of 6 min) in 39 stable patients with previous MI. Peak-systolic (Speak-sys) circumferential strain, radial strain and longitudinal strain were assessed by STI. Radionuclide myocardial perfusion/metabolic imaging served as the "gold standard" to detection of myocardial viability.
Results: (1) There were 215 viable and 153 non-viable regions among 368 abnormal motion segments out of 624 segments in 39 MI patients according to radionuclide imaging results. (2) Speak-sys was similar between viable and nonviable myocardium at rest (all P > 0.05). After adenosine infusion, radial Speak-sys [(37.98 ± 5.45)% vs. (30.22 ± 5.47)%], longitudinal Speak-sys [(-23.71 ± 4.53)% vs. (-17.52 ± 4.34)%] increased significantly (P < 0.05)in viable segments compared to baseline levels and were significantly higher than in nonviable segments radial Speak-sys [(37.98 ± 5.45)% vs. (30.12 ± 5.37)%] and longitudinal Speak-sys [(-23.71 ± 4.53)% vs. (-16.95 ± 4.62)%] (P < 0.05), while remained unchanged in nonviable segments before and after adenosine infusion. Circumferential Speak-sys was similar before and after adenosine infusion in both viable and nonviable segments (all P > 0.05). (3) Delta radial strain change > 9.8% has a sensitivity of 82.3% and a specificity of 81.1% whereas a delta change of longitudinal strain > 16.5% has a sensitivity of 83.5% and a specificity of 92.3% for detecting viable segments.
Conclusions: Speckle tracking imaging combined with adenosine stress echocardiography could serve as a new and reliable method of assessing myocardial viability.