BACKGROUND: Intraventricular obstruction (IVO) during dobutamine stress echocardiogram (DSE) may be associated with or reproduce symptoms. Predictors of IVO are not well established. METHODS: 149 patients were studied at rest and during DSE. The normal range of the left ventricular outflow tract (LVOT) velocities was investigated in 68 healthy patients. RESULTS: 19 patients (13%) developed IVO (peak LVOT velocity > 271 cm/sec). A significant linear correlation was observed between peak LVOT velocity during DSE and the following rest parameters: LV end-diastolic dimension (r =-0.20, P = 0.018), LV end-systolic dimension (r =- 0.27, P = 0.001), relative wall thickness (r = 0.23, P = 0.006), shortening fraction (r = 0.24, P = 0.004), LVOT diameter (r =- 0.20, P = 0.023) and LVOT velocity (r = 0.29, P < 0.0001). Only relative wall thickness (P = 0.012) and LVOT diameter (P = 0.027) were independent predictors of IVO. As a dichotomous variable, a relative wall thickness > or =0.44 was the only independent predictor of IVO (OR 5.7, 95% CI 1.6-20, P = 0.006), with sensitivity, specificity, negative predictive value, and positive predictive value of 77%, 62%, 95%, and 21%, respectively, and global accuracy of 63% (area under the ROC curve = 0.7). IVO was significantly associated with general cardiovascular symptoms (P = 0.0006) and with chest pain (P = 0.008). CONCLUSIONS: Relative wall thickness and LVOT diameter were independent predictors of obstruction. As a dichotomous variable, a relative wall thickness < or = 0.44 was the only independent predictor of dynamic IVO.
BACKGROUND: Intraventricular obstruction (IVO) during dobutamine stress echocardiogram (DSE) may be associated with or reproduce symptoms. Predictors of IVO are not well established. METHODS: 149 patients were studied at rest and during DSE. The normal range of the left ventricular outflow tract (LVOT) velocities was investigated in 68 healthy patients. RESULTS: 19 patients (13%) developed IVO (peak LVOT velocity > 271 cm/sec). A significant linear correlation was observed between peak LVOT velocity during DSE and the following rest parameters: LV end-diastolic dimension (r =-0.20, P = 0.018), LV end-systolic dimension (r =- 0.27, P = 0.001), relative wall thickness (r = 0.23, P = 0.006), shortening fraction (r = 0.24, P = 0.004), LVOT diameter (r =- 0.20, P = 0.023) and LVOT velocity (r = 0.29, P < 0.0001). Only relative wall thickness (P = 0.012) and LVOT diameter (P = 0.027) were independent predictors of IVO. As a dichotomous variable, a relative wall thickness > or =0.44 was the only independent predictor of IVO (OR 5.7, 95% CI 1.6-20, P = 0.006), with sensitivity, specificity, negative predictive value, and positive predictive value of 77%, 62%, 95%, and 21%, respectively, and global accuracy of 63% (area under the ROC curve = 0.7). IVO was significantly associated with general cardiovascular symptoms (P = 0.0006) and with chest pain (P = 0.008). CONCLUSIONS: Relative wall thickness and LVOT diameter were independent predictors of obstruction. As a dichotomous variable, a relative wall thickness < or = 0.44 was the only independent predictor of dynamic IVO.