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Background: Impaired or stunned regional left ventricular (LV) diastolic function could occur after transient severe myocardial ischemia associated with coronary vasospasm (CV). Three-dimensional speckle tracking imaging (3D-SI) has been recently developed to quantify LV stain using complete pyramidal datasets. We investigated whether impaired regional LV relaxation could actually be diagnosed using 3D-SI and how long the regional diastolic dysfunction persists after CV.Method: Thirty-eight consecutive patients (26 men, 60 ± 9 years) with variant angina were studied. In all patients, coronary artery spasm was angiographically demonstrated in ≥1 major coronary artery during angina provoked by intracoronary injection of acetylcholine. The 3D-SI was obtained by using an ultrasound system (ARTIDA, Toshiba Medical Systems) with PST-25SX probe. The 3D-SI software automatically divided the LV into 16 segments and generated corresponding time-strain curves from each segment. The end systolic values of radial strain at the closure of aortic valve (A) and at the one-third point of diastole duration (B) were measured. 3D-SI diastolic index (3D-SIDI) was defined as (A-B)/A ×100% to assess the regional LV active relaxation. Three major coronary perfusion territories were assigned as :1) the mid-anteroseptal segment to the left anterior descending coronary artery; 2) the mid- lateral segment to the left circumflex branch; and 3) the mid-inferior segment to the right coronary artery. The mean 3D-SIDI in 30 control subjects was 84 ± 6%, 86 ± 8%, 83 ± 7% in the anteroseptal, lateral, and inferior segments, respectively. The first 3D-SI study was performed within 1 week before coronary angiography (CAG), and the second study was performed approximately 24 hours after CAG. Study patients were treated with calcium entry blockers and nitroglycerin throughout the study period. The 3D-SI study was then repeated 1, 2, and 4 weeks after CAG.Results: The mean 3D-SIDI was -14.3 ± 15.8% in the 45 territories perfused by the coronary arteries with spasm, similar to that noted before CAG (-10.6 ± 12.9%). In study patients, the 3D-SIDI of the 38 territories perfused by the coronary arteries with spasm significantly increased 21.7 ± 11.5%, 48 ± 18.6%, and 80 ± 8.7% (p < 0.05) during repeated 3D-SI study. The index had no improvement in the 7 patients who experienced recurrent angina despite treatment.Conclusion: Echocardiographic evaluation of regional myocardial wall motion by 3D-SI is a useful method for detecting prolonged post-ischemic diastolic stunning and for identifying the angina-provoking vessel in patients with CV.