QUANTIFICATION OF REGIONAL MYOCARDIAL FUNCTION: IMPROVED DETECTION OF MYOCARDIAL ISCHEMIA IN DIABETIC PATIENTS DURING DOBUTAMINE DOPPLER MYOCARDIAL IMAGING ECHOCARDIOGRAPHY

The aim of the study was to evaluate the value of pulsed wave Doppler myocardial imaging (PW DMI) in detecting myocardial ischemia (mi) during dobutamine stress echocardiography (DSE) in diabetic patients. Methods: We studied 40 diabetic patients with known or suspected coronary artery disease. In all patients DSE (from 5 up to 40 mcg/kg/min infused in 3‐minute stages, plus atropine 1 mg if needed) was performed. DSE identified ischemia by the occurrence of wall motion abnormalities (WMA) with stress (positive DSE). Apical views were used to assess myocardial velocities (mv; Acuson‐ Sequoia, PW DMI) on baseline and at peak stres. The left ventricle was divided into 11 segments. The sample volume was placed in each adequately visualized segment and in each segment we measured peak mv of systolic (S), early (E), and late (A) diastolic waves and calculated their ratio (E/A) as an index of regional diastolic function. Results: Myocardial velocities were measured in 374 (85%) of 440 possible myocardial segments. During DSE in 21 (52.5%) patients WMA were detected in 73 (37%) of 197 adequately visualized segments, while in 19 (47.5%) patients WMA did not appear. Of 21 patients with DSE‐provoked WMA, in 9 (42.9%) patients symptomatic and in 12 (57.1%) patients silent mi appeared. In segments with DSE‐provoked symptomatic and silent WMA the ratio of E/A decreased by 23.7% and 20.1% (p < 0.001 for both) and S decreased by 18.7% (p < 0.005) and 14.4% (p < 0.02) compared to baseline values. Of 301 segments without DSE‐induced WMA in 13 (4.3%) segments (6 in patients with positive and 7 segments in patients with negative DSE) we also found inversion of the E/A ratio (from 1.04 ± 0.08 to 0.94 ± 0.09, p < 0.005). In 288 other segments without WMA ratio E/A and S mv significantly increased (p < 0.001 for both). Conclusion: Quantification of regional myocardial function during conventional DSE in diabetic patients showed that symptomatic as well as silent mi is associated with significant decrease of E/A ratio and S mv but changes are more pronounced in symptomatic mi. Inverted regional E/A ratio may uncover super‐silent mi, which is not sufficient to provoke WMA.