Introduction: Detection of regional stunned myocardium with impaired diastolic function is known as a sensitive tool for diagnosis of myocardial ischemia. The aim of this study is to assess the mechanism of diastolic stunning with diastolic strain rate during coronary vasospasm.
Methods: We obtained the three consecutive cycles of mid LV short-axis image at baseline, spasm provocation and recovery in 40 patients with positive ergonovine echocardiography. Using offline speckle tracking software, LV radial and circumferential strain was obtained. In addition to early (SRe) and late (SRa) diastolic strain rate, very early diastolic strain rate (SRi) was also obtained.
Results: Among the 40 patients, 22 patients could be analyzed. Regional radial strain was significantly reduced during vasospasm provocation (58.4± 24.3% to 36.2± 23.3%, p=0.004). Post systolic thickening was detected in circumferential strain, but not in radial strain. SRi was significantly reduced during vasospasm (-0.56± 0.48/s to -0.08± 0.46/s, p=0.028). SRE was significantly increased during vasospasm and nitrate (-1.74± 0.82/s vs. -1.95± 0.74/s vs. -2.24± 0.77/s, p=0.014). Time to SRE was significantly delayed at nitrate.
Conclusions: Diastolic stunning may be caused by delayed occurrence of increased early diastolic strain rate and decrease of very early diastolic strain rate
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