Strain rate analysis allows detection of differences in diastolic function between viable and nonviable myocardial segments

Abstract

Analysis of diastolic function for assessment of myocardial viability has not been evaluated. Strain rate (SR) analysis allows quantitative segmental analysis of myocardial function and has been used during dobutamine stimulation for assessment of systolic functional reserve. In 37 patients with ischemic left ventricular dysfunction diastolic function was evaluated at rest and during low-dose dobutamine stimulation (10 mug/kg/min) using SR imaging and related to F18-fluorodeoxyglucose positron emission tomography. Analysis of peak early (E waves) and late (A waves) diastolic myocardial SR was performed using apical views. In all, 317 segments had normal function at rest by 2-dimensional echocardiography. A total of 192 segments with dyssynergy at rest were classified by positron emission tomography as viable in 94 cases and nonviable in 98 cases. Dys-synergic segments had lower E and A waves SR compared with normal contracting segments. There were no significant differences in peak E and A waves SR at rest between dys-synergic viable and nonviable segments. With dobutamine stimulation peak E waves SR increased significantly for viable segments (0.89 +/- 0.51-1.06 +/- 0.51 L/s, P < .01) whereas it was unchanged for nonviable segments (0.77 +/- 0.49-0.78 +/- 0.48 L/s, P = .835). Peak A waves SR increased for viable (0.71 +/- 0.55-1.00 +/- 0.56 L/s, P < .01) and nonviable (0.57 +/- 0.47-0.71 +/- 0.58 L/s, P = .023) segments. However, during dobutamine stimulation peak A waves SR was larger ( P < .001) for viable than for nonviable segments. In conclusion, normal contracting segments at rest have higher E and A waves SR compared with dys-synergic segments. Dys-synergic viable myocardial segments demonstrate an increase in E and A waves SR with dobutamine stimulation whereas nonviable segments are less responsive to dobutamine.