Improved identification of viable myocardium using second harmonic imagingduring dobutamine stress echo cardiography

Objective-To determine whether, compared with fundamental imaging, second h armonic imaging can improve the accuracy of dobutamine stress echocardiogra phy for identifying viable myocardium, using nuclear imaging as a reference . Patients-30 patients with chronic left ventricular dysfunction (mean (SD) a ge, 60 (8) years; 22 men). Methods-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 tomog raphy (DISA-SPECT) with tetrofosmin/F-18-fluorodeoxyglucose on a separate d ay. Myocardial viability was considered present by dobutamine stress echo c ardiography when segments with severe dysfunction showed a biphasic sustain ed improvement or an ischaemic response. Viability criteria on DISA-SPECT w ere normal or mildly reduced perfusion and metabolism, or perfusion/metabol ism mismatch. Results-Using fundamental imaging, 330 segments showed severe dysfunction a t baseline; 144 (44%) were considered viable. The agreement between dobutam ine stress echocardiography by fundamental imaging and DISA-SPECT was 78%, K = 0.56. Using second harmonic imaging, 288 segments showed severe dysfunc tion; 138 (48%) were viable. The agreement between dobutamine stress echoca rdiography and DISA-SPECT was significantly better when second harmonic ima ging was used (89%, kappa = 0.77, p = 0.001 v fundamental imaging). Conclusions-Second harmonic imaging applied during dobutamine stress echo c ardiography increases the agreement with DISA-SPECT for detecting myocardia l viability.