Search

Objective: The aim of this study was to evaluate the effect of low dose dobutamine (LDD) on various diastolic function parameters in patients without wall motion abnormality., Methods: Thirty-one volunteer patients who had no regional wall motion abnormality were included in the study. Echocardiographic measurements were taken both at pre-dobutamine and during LDD infusion. The peak E velocity, A velocity, the E/A ratio, deceleration time (DT), isovolumetric relaxation time (IVRT), myocardial performance index (MPI) and flow propagation velocity (FPV) were assessed as left ventricular diastolic function parameters. Tissue Doppler velocities were also obtained in order to calculate the E/Em and Em/Am ratios., Results: No significant changes were observed in heart rate, E velocity, A velocity, E/A ratio, E/Em ratio, Em/Am ratio, systolic and diastolic blood pressure with LDD. With LDD, DT (239+/-40 ms vs. 201+/-31 ms, p<0.001), IVRT (109+/-12 ms vs. 94+/-11 ms, p<0.001) and MPI (0.57+/-0.15 vs. 0.44+/-0.22, p<0.001) were found to be decreased, while there was an increase in FPV (45+/-8 cm/s vs. 59+/-10 cm/s, p<0.001) and ejection fraction (64+/-6% vs. 66+/-7%, p<0.05)., Conclusion: Low dose dobutamine (5 mcg/kg of body weight) improves left ventricular relaxation in patients with normal wall motion, while it has no effect on left ventricular filling pressure index.

Some patients with hypertrophic nonobstructive cardiomyopathy (HNCM) suffer symptoms resembling those in obstructive type despite no left ventricular outflow tract (LVOT) gradient could be detected on resting echocardiography. To investigate the value of dobutamine stress echocardiography (DSE) in determining the dynamic left ventricular (LV) obstruction of patients with HNCM. The study was conducted on 31 patients who were diagnosed HNCM on resting echocardiography and 9 healthy person as a control group. Intraventricular flow acceleration of > 3 m/sec on DSE was accepted as dynamic LVOT obstruction. Group 1 and 2 included patients without and with dynamic LVOT obstruction, respectively. The occurrence of chest pain and dyspnea seen during DSE was more frequent in group 2 than group 1 and control group. The frequency of SAM was significantly higher (p < 0.05) and the septal angle was significantly lower (p < 0.001) in Group 2. The presence of SAM significantly correlated with the peak gradient (r = 0.61, p < 0.001). The septal angle had significant negative correlations with the peak gradient (r = -0.77, p < 0.001) reached at DSE. The relative risk for peak gradient was highest when septal angle was < or = 100 degrees, with a sensitivity of 93%, specificity of 80%, positive predictive value of 82%, negative predictive value of 92%, and predictive accuracy of 87%. DSE is a reliable tool for the diagnosis of dynamic LV obstruction in patients with HNCM. The presence of SAM together with a low septal angle is highly predictive for the presence of a dynamic LVOT obstruction detected by DSE.

Objective: This study was planned to evaluate the dynamic left ventricular outflow tract (LVOT) obstruction by using dobutamine stress echocardiography (DSE) in patients with asymmetric septal hypertrophy and/or septal bulging, who have no signs of LVOT gradient detected by conventional echocardiography, with symptoms mimicking hypertrophic obstructive cardiomyopathy (HOCM)., Methods: In sixty-one consecutive patients referred to our echocardiography laboratory with HOCM pre-diagnosis, exercise dyspnea and limitation of exercise capacity were evaluated. DSE was performed in 31 patients who fulfilled the inclusion criteria. Patients were divided into two groups according to the degree of dynamic gradient increase above baseline values during stress-test (Group 1 < 30 mmHg, Group 2 > 30 mmHg). Left ventricular diameters, septum and posterior wall thicknesses, ejection fraction, LVOT and aortic root diameters, presence of septal bulging and systolic anterior motion (SAM) and degree of septal angulation were sought., Results: There were no significant differences between groups by means of LV diameters, septum and posterior wall thicknesses, EF, LVOT and aortic root diameters, presence of septal bulging (p > 0.05); whereas there were significant differences in SAM and degree of septal angulation (p < 0.05 and p < 0.0001, respectively). Systolic anterior motion (r = 0.61, p < 0.0001) and degree of septal angulation (r = -0.71, p < 0.001) correlated significantly with the dynamic gradient increase., Conclusion: Presence of SAM and degree of septal angulation obtained by DSE are reliable parameters to determine dynamic LVOT obstruction in patients who have asymmetric septal hypertrophy and septal bulging with no gradient on LVOT by conventional echocardiography.

False positive inferior wall perfusion defects restrict the accuracy of SPECT in diagnosis of coronary artery disease (CAD). Pulse-Wave Tissue Doppler (PWTD) has been recently proposed to assess regional wall motion velocities. The objectives of this study were to evaluate the presence of CAD by using PWTD during dobutamine stress echocardiography (DSE) in patients with an inferior perfusion defect detected by SPECT and compare PWTD parameters of normal cases with patients who had inferior perfusion defect and CAD. Sixty-five patients (mean age 58 +/- 8 years, 30 men) with a normal LV systolic function at rest according to echocardiographic evaluation with an inferior ischemia determined by SPECT and a control group (CG) of 34 normal cases (mean age 56 +/- 7 years, 16 men) were included in this study. All patients underwent a standard DSE (up to 40 microg / kg / min with additional atropine during sub-maximum heart rate responses). Pulse-wave Doppler tissue sampling of inferior wall was performed in the apical 2-chamber view at rest and stress. The coronary angiography was performed within 24 hours. The results were evaluated for the prediction of significant right coronary artery (RCA) and / or left circumflex coronary artery (CX) with narrowing (> or = 50% diameter stenosis, assessed by quantitative coronary angiography). It was observed that the peak stress mean E / A ratio was lower in patients with CAD when compared to patients without CAD (0.78 +/- 0.2 versus 1.29 +/- 0.11 p < 0.0001). Also the peak stress E / A ratio of normal cases was significantly higher than patients who had CAD (1.19 +/- 0.3 versus 0.78 +/- 0.2 p < 0.0001). When the cut off point for the E / A ratio was determined as 1, the sensitivity and specificity of dobutamine stress PWTD E / A were 89% and 86 %, respectively. The peak stress E / A ratio was higher than 1 in all patients with a false positive perfusion defect. Systolic S velocity increase during DSE was significantly lower in patients with CAD (54 % +/- 17 versus 99 % +/- 24 p = 0.01). The analysis of S velocity increase yielded 81% sensitivity and 76 % specificity for prediction of CAD when a 70 % increase was accepted as a cut-off value. Pulse-wave Doppler tissue sampling during DSE may help to identify false positive inferior wall defects detected by SPECT.

An abstract of the article "Assessing the Effect of Low dose Dobutamine on Various Diastolic Function Indexes" by S. Gorgulu and colleagues is presented.