Improved identification of viable myocardium using second harmonic imaging during dobutamine stress echocardiography.

Abstract

To determine whether, compared with fundamental imaging, second harmonic imaging can improve the accuracy of dobutamine stress echocardiography for identifying viable myocardium, using nuclear imaging as a reference. 30 patients with chronic left ventricular dysfunction (mean (SD) age, 60 (8) years; 22 men). Dobutamine stress echocardiography was carried out in all patients using both fundamental and second harmonic imaging. All patients underwent dual isotope simultaneous acquisition single photon emission computed tomography (DISA-SPECT) with (99m)technetium-tetrofosmin/(18)F-fluorodeoxyglucose on a separate day. Myocardial viability was considered present by dobutamine stress echocardiography when segments with severe dysfunction showed a biphasic sustained improvement or an ischaemic response. Viability criteria on DISA-SPECT were normal or mildly reduced perfusion and metabolism, or perfusion/metabolism mismatch. Using fundamental imaging, 330 segments showed severe dysfunction at baseline; 144 (44%) were considered viable. The agreement between dobutamine stress echocardiography by fundamental imaging and DISA-SPECT was 78%, kappa = 0.56. Using second harmonic imaging, 288 segments showed severe dysfunction; 138 (48%) were viable. The agreement between dobutamine stress echocardiography and DISA-SPECT was significantly better when second harmonic imaging was used (89%, kappa = 0.77, p = 0.001 v fundamental imaging). Second harmonic imaging applied during dobutamine stress echocardiography increases the agreement with DISA-SPECT for detecting myocardial viability.