Dobutamine Stress In Patients Research Articles

Haemodynamic left-ventricular changes during dobutamine stress in patients with atrial septal defect assessed with magnetic resonance imaging-based pressure-volume loops.

Atrial septal defect (ASD) results in a left-to-right shunt causing right-ventricular(RV) volume overload and decreased cardiac output from the left ventricle. Pressure-volume (PV) loops enable comprehensive assessment of ventricular function and might increase understanding of the pathophysiology of ASD. The aim of this study was to investigate if left-ventricular (LV) haemodynamic response to stress in patients with ASD differs from controls. Patients with ASD (n = 18, age 51 ± 18) and healthy controls (n = 16, age 35 ± 13) underwent cardiac magnetic resonance (CMR) and brachial cuff pressure measurements at rest and during dobutamine stress. An in-house, validatedmethod was used to compute PV loops. Patients had lower stroke work, potential energy and external power at rest than controls (p < 0.001;p < 0.05;p < 0.05). Stroke work and external power increased and potential energy decreased during stress in patients (p < 0.05;p < 0.0001;p < 0.01) and controls (p < 0.0001;p < 0.001;p < 0.01). Contractility and arterial elastance at rest were higher in patients than controls (p < 0.01;p < 0.01). Contractility increased during stress in both groups (p < 0.0001;p < 0.001). There was no difference between patients and controls in arterio-ventricular coupling. LV haemodynamic response to stress can be assessed using noninvasive PV loops derived from CMR and brachial blood pressure. Patients with ASD had normal LV energy efficiency, in contrast to other patient groups with decreased cardiac output. Data suggest that patients with ASD had an increased inotropic level at rest with high contractility and heart rate but were able to respond with a further increase during stress, albeit to not as high a cardiac output as controls.

Quantitative blood flow evaluation of vasodilation-stress compared with dobutamine-stress in patients with end-stage liver disease using 82Rb PET/CT

BackgroundOur aim was to determine if end-stage liver disease (ESLD) is associated with an attenuated response to vasodilator-stress or dobutamine-stress using 82Rb-PET MPI with blood flow quantification. Methods and ResultsPre-liver transplant patients who had a normal dipyridamole-stress (n = 27) or dobutamine-stress (n = 26) 82Rb PET/CT MPI study with no identifiable coronary artery calcium were identified retrospectively and compared to a prospectively identified low-risk of liver disease dipyridamole-stress control group (n = 20). The dipyridamole-stress liver disease group had a lower myocardial flow reserve (MFR) (1.89 ± 0.79) than the control group (2.79 ± 0.96, P < .05). The dobutamine-stress group had a higher MFR than both other groups (3.69 ± 1.49, P < .05). A moderate negative correlation between MELD score and MFR was demonstrated for the dipyridamole-stress liver disease group (r = − 0.473, P < .05). This correlation was not observed for the dobutamine-stress liver disease group (r = − 0.253, P = .21). The liver failure group as a whole (n = 53) had a higher resting myocardial blood flow (0.97 ± 0.33 mL/min/g) than the control group (0.82 ± 0.26, P < .05). ConclusionDipyridamole demonstrates an attenuated vasodilatory response in ESLD patients compared to a non-ESLD control group related to higher resting blood flow and comparatively reduced stress blood flow. Dobutamine does not demonstrate this effect implying it may be the preferred pharmacologic MPI stress agent for ESLD patients.

Additional diagnostic accuracy of global longitudinal strain at peak dobutamine stress in patients with moderate pretest probability of coronary artery disease.

Previous studies confirmed the feasibility of 2D speckle tracking echocardiography (2D STE) during dobutamine stress echocardiography (DSE) in assessing myocardial ischemia in patients with previous myocardial infarction. It is unknown whether it improves the diagnostic accuracy in young patients with intermediate pretest probability for coronary artery disease (CAD) and no prior cardiovascular events. We prospectively studied 101 patients by DSE and STE, followed by coronary angiography within 1month. Significant CAD was defined as diameter stenosis≥50%. Receiver operating characteristic analysis obtained global longitudinal strain (GLS) cutoff values of significant area under the curve (AUC). Mean age: 53±8years, 56% females, 49 had significant CAD (group 1) and 52 had normal/mild CAD (group 2); no significant baseline differences except more males in group 1 (P: .002). DSE sensitivity and specificity for CAD were 79.6% and 92.3%, respectively, positive predictive value (PPV): 90.6%, negative predictive value (NPV): 82.7%, and diagnostic accuracy: 86%. At peak stress, all strain parameters were significantly lower in group 1. However, GLS had the highest AUC: 0.88, P: <.001. GLS cutoff value≤-20.5 had 89.8% sensitivity, 84.6% specificity, 84.6% PPV, 89.8% NPV, and 87% diagnostic accuracy. Combining GLS cutoff with DSE had higher AUC than either alone (0.9, P<.001): 95.9% sensitivity, 84.6% specificity, 85.5% PPV, 95.7% NPV, and 90% diagnostic accuracy. 2D-STE-derived GLS increases DSE precision to detect CAD in intermediate pretest probability patients: It improves DSE sensitivity, NPV, and accuracy. It is reproducible and has comparable specificity.

Chronic Dipeptidyl Peptidase-4 Inhibition With Sitagliptin Is Associated With Sustained Protection Against Ischemic Left Ventricular Dysfunction in a Pilot Study of Patients With Type 2 Diabetes Mellitus and Coronary Artery Disease

The incretin hormone, glucagon-like peptide-1, promotes myocardial glucose uptake and may improve myocardial tolerance to ischemia. Endogenous glucagon-like peptide-1 (7-36) is augmented by pharmacological inhibition of dipeptidyl peptidase-4. We investigated whether chronic dipeptidyl peptidase-4 inhibition by sitagliptin protected against ischemic left ventricular dysfunction during dobutamine stress in patients with type 2 diabetes mellitus and coronary artery disease. A total of 19 patients with type 2 diabetes mellitus underwent dobutamine stress echocardiography with tissue Doppler imaging on 2 separate occasions: the first (control) while receiving oral hypoglycemic agents, and the second after the addition of sitagliptin (100 mg once daily) for ≈4 weeks. Sitagliptin increased plasma glucagon-like peptide-1 (7-36) levels and, at peak stress, enhanced both global (ejection fraction, 70.5±7.0 versus 65.7±8.0%; P<0.0001; mitral annular systolic velocity, 11.7±2.6 versus 10.9±2.3 cm/s; P=0.01) and regional left ventricular function, assessed by peak systolic velocity and strain rate in 12 paired, nonapical segments. This was predominantly because of a cardioprotective effect on ischemic segments (strain rate in ischemic segments, -2.27±0.65 versus -1.98±0.58 s(-1); P=0.001), whereas no effect was seen in nonischemic segments (-2.19±0.48 versus -2.18±0.54 s(-1); P=0.87). At 30 minutes recovery, dipeptidyl peptidase-4 inhibition mitigated the postischemic stunning seen in the control scan. The addition of dipeptidyl peptidase-4 inhibitor therapy with sitagliptin to the treatment regime of patients with type 2 diabetes mellitus and coronary artery disease is associated with a sustained improvement in myocardial performance during dobutamine stress and a reduction in postischemic stunning. URL: http://www.isrctn.org. Unique identifier ISRCTN61646154.

Fractional Flow Reserve With Dobutamine Challenge and Coronary Microvascular Endothelial Dysfunction in Symptomatic Myocardial Bridging

Myocardial bridging (MB) results in compression of the coronary artery lumen in systole, extending into diastole with resultant hemodynamic alternation as reflected by fractional flow reserve (FFR). MB has also been associated with coronary endothelial dysfunction. The objective of this study was to investigate relationship between FFR with dobutamine challenge and coronary microvascular endothelial dysfunction in symptomatic MB. Seventeen consecutive patients who had cardiac catheterization assessment of MB were enrolled. The patients were divided into 2 groups according to normal (% increase in coronary blood flow [%CBF] ≥50%, n=7) or impaired (%CBF <50%, n=10) coronary microvascular endothelial function assessed on vasoreactivity in the coronary artery with intracoronary infusion of acetylcholine (Ach). Myocardial ischemia was then assessed using FFR at rest and during i.v. dobutamine infusion challenge across the MB with intracoronary pressure wires. FFR was significantly decreased at peak dobutamine infusion compared to at rest in the impaired group (0.85±0.06 vs. 0.91±0.05, P=0.001), but not in the normal group (0.93±0.05 vs. 0.91±0.07, P=0.618). Both FFR at rest and at peak dobutamine infusion had a positive correlation with %CBF by Ach in the impaired group (r(2)=0.46, P=0.030; r(2)=0.52, P=0.018, respectively). Microvascular endothelial dysfunction was associated with decreased FFR at peak dobutamine stress in patients with symptomatic MB.

Assessment of myocardial viability using early systolic mitral annular motion velocities responses to dobutamine infusion in patients with previous myocardial infarction

Dobutamine stress echocardiography (DSE) is widely used for detection of myocardial viability. The main limitation of DSE is its subjective interpretation. Assessment of mitral annular motion velocities with tissue Doppler imaging is simple and quantitative measurement. It is to determine the relationship between myocardial viability and regional systolic mitral annular motion velocity response to dobutamine stress in patients with previous myocardial infarction with pulsed tissue Doppler imaging (TDI). Our study group included 101 patients with previous myocardial infarction. All the patients underwent conventional DSE and dobutamine stress tissue Doppler echocardiography (DSTDE) measuring velocities of presystolic wave (SW1) and peak systolic wave (SW2) at rest and during low-dose dobutamine infusion. After exclusion of the normokinetic walls, we analyzed 505 walls.(Table 1) Using the conventional DSE as the gold standard for detection of myocardial viability, the sensitivity of the DSTDE using SW1 for detection of viability was 94.8% and its specificity was 91.7%, while the sensitivity using SW2 for detection of viability was 87.8%, and its specificity was 81.5%. The presystolic wave during DSTDE showed a greater sensitivity and specificity for the prediction of myocardial viability than the systolic wave.

Myocardial 123I-MIBG scintigraphy predicts an impairment in myocardial functional reserve during dobutamine stress in patients with idiopathic dilated cardiomyopathy

We investigated whether myocardial (123)I-metaiodobenzylguanidine ((123)I-MIBG) scintigraphy predicts impairment of myocardial functional reserve in response to dobutamine stress in patients with idiopathic dilated cardiomyopathy (DCM). Forty DCM patients (LVEF 39 ± 12 %) underwent myocardial (123)I-MIBG scintigraphy, echocardiography, and cardiac catheterization. Myocardial (123)I-MIBG uptake was quantified as the delayed heart to mediastinum (H/M) ratio and washout rate (WR). Local denervation was evaluated on polar map images. LV dP/dt (max) and T(1/2) were determined from left ventricular pressure curves at baseline and during dobutamine infusion (15 μg/kg /min). Patients were classified into two groups as follows: group A comprised 21 patients showing a delayed H/M ratio of <1.9 (median value); group B comprised 19 patients showing a delayed H/M ratio of ≥ 1.9. The percentage change in heart rate (%HR), LV dP/dt (max) (%LV dP/dt (max)), and T (1/2) (%T (1/2)) from baseline to dobutamine stress were significantly more reduced in group A than in group B (39.3 ± 20.2 %, 55.2 ± 24.1 %, p < 0.01; 102.3 ± 46.3 %, 152.0 ± 72.3 %, p < 0.05; 38.7 ± 15.3 %, 46.9 ± 15.4 %, p < 0.05, respectively). No significant differences between the two groups were observed in the echocardiographic parameters or baseline cardiac catheterization parameters. Significant correlations were found between delayed H/M ratio and %HR (r = 0.35, p < 0.05), %LV dP/dt (max) (r = 0.45, p < 0.05) and %T (1/2) (r = 0.34, p < 0.05). Significant inverse correlations were also found between WR and %HR (r = -0.37, p < 0.05), %LV dP/dt (max) (r = -0.60, p < 0.0001), and %T (1/2) (r = -0.34, p < 0.05). SPECT images revealed enhanced denervation from the inferoposterior to anterior wall in accordance with the advancement of global denervation. Reduced (123)I-MIBG uptake and increased washout were related to impairment in adrenergic myocardial functional reserve in idiopathic DCM.

135 Chronic DPP-4 inhibition by sitagliptin enhances both global and regional myocardial function during dobutamine stress in patients with type 2 diabetes mellitus and coronary artery disease

BackgroundGlucagon-like peptide-1 (GLP-1) is an incretin hormone secreted by the gut in response to the oral ingestion of nutrients. Through augmentation of myocardial glucose uptake and subsequent reduction in fatty...

Influence of preload and afterload on stroke volume response to low-dose dobutamine stress in patients with non-ischemic heart failure: A cardiac MR study

BackgroundLack of increase in left ventricular (LV) stroke volume (SV) during low-dose dobutamine stress (LDD) is attributed to exhausted cardiac contractile reserve in failing heart. However, the role of the afterload and preload in SV changes is underestimated. The aim of the study was to investigate the effects of LDD on preload reserve and afterload in patients with non-ischemic heart failure. Methods58 patients (age 62years) underwent LDD (up to 20μg/kg/min) using cardiac magnetic resonance. ResultsLV-SV increased by 27% in 24 patients (p<0.001) (SV+), while decreased by 19% in 22 patients (p<0.001) (SV−). The LDD-to-rest reduction in preload, as defined by LV end-diastolic volume (EDV), was more pronounced in SV− than SV+ (24% and 8% respectively, p<0.05). The LLD-to-rest increase in systolic blood pressure to LV end systolic volume ratio, an index of LV contractility, was higher but not statistically different in SV+ in comparison to SV− (70% vs 48%, p=ns). Systemic vascular resistance during LDD tended to be higher in SV− (23%, p=ns), while it was significantly reduced in SV+ (9.5%, p<0.011), whereas arterial elastance (Ea) increased in SV− (30%, p<0.001) but decreased in SV+ (0.5%, p=0.04). At multivariable regression models LV-EF, LV-EDV and Ea significantly contributed to LV-SV changes in all patients. Also among SV+ and SV− LV-EDV and Ea revealed significant contribution to LV-SV change. ConclusionsAt similar contractile reserve response, the lack of LDD-induced increase in LV-SV, can be related to reduced preload reserve as well as to increased afterload.

Cardioprotection against ischaemia induced by dobutamine stress using glucagon-like peptide-1 in patients with coronary artery disease

BackgroundGlucagon-like peptide-1 (GLP-1) is an incretin hormone which has been shown to promote myocardial glucose uptake. Its pharmacological properties as a cardioprotective agent are attractive because it has a short...

Parallel imaging and dobutamine stress magnetic resonance imaging in patients with atypical chest pain or equivocal ECG not suitable for stress echocardiography

The aim of this study was to evaluate the clinical utility of cardiac magnetic resonance imaging (MRI) with dobutamine stress in patients with atypical chest pain or equivocal electrocardiography (ECG) stress test, not suitable for stress echocardiography, using steady-state free-precession and parallel imaging technique. Thirty-three patients (22 men, 11 women; mean age 62.4 years) underwent MRI with a 1.5-Tesla imager (General Electric, HD). We used an eight-channel phase-array dedicated coil. The MRI protocol included short-axis cine steady-state sequences with four-chamber parallel imaging of the left ventricle outflow tract at rest and after stress induction. Images were acquired 3 min after the intravenous injection of 5,10, 20, 30 or 40 microg/kg/min dobutamine. MRIs were analysed both at rest and at incremental dobutamine doses. Results were considered positive for coronary artery disease (CAD) if any new or worsening wall motion abnormality developed during the stress test. Twenty-two patients underwent coronary angiography; in the remaining ten, survival free from cardiovascular events over at least 9 months was considered as absence of disease. One patient presented severe hypertension at rest and was excluded from our study. We analysed 960 segments and observed appearance or worsening of kinesis in 29 different segments in seven patients. Seven patients were considered positive for CAD on the basis of new or worsening wall motion abnormalities during dobutamine stress, yielding an overall sensitivity of 85% and a specificity of 100% in CAD detection. Dobutamine stress cardiac MRI is an accurate method for assessing myocardial ischaemia in patients with CAD, and it could be useful as a noninvasive tool for excluding the disease. The increase in signal intensity and acquisition speed obtained by using steady-state free precession with parallel imaging proved useful in increasing test specificity with respect to previous similar studies.

Patients After Atrial Switch Operation for Transposition of the Great Arteries Can Not Increase Stroke Volume Under Dobutamine Stress as Opposed to Patients With Congenitally Corrected Transposition

Patients after atrial switch operation for transposition of the great arteries have limited exercise performance. Rigid atrial baffles may cause a relative preload reduction. Previous studies have had suboptimal control groups, which ideally should consist of patients with congenitally corrected transposition of the great arteries (ccTGA) without previous heart surgery, having a systemic right ventricle, but lacking rigid atrial baffles. Therefore the aim of this study was to test the impact of atrial baffles by comparing 12 atrial switch patients with 11 ccTGA patients. Systemic right ventricular stroke volume (SV), heart rate, cardiac index, and other parameters were assessed during rest and dobutamine stress magnetic resonance imaging. The most important difference between the groups was that the atrial switch patients could not increase SV during stress, whereas ccTGA patients increased it significantly. There was no difference between groups in the rise of the cardiac index. Heart rate increased significantly more in atrial switch patients than in ccTGA patients. The results support the hypothesis that atrial baffles restrict a rise in SV under dobutamine stress in patients after atrial switch operation for transposition of the great arteries.

Systemic ventricular response to dobutamine stress in patients with mustard repair for transposition of the great arteries

Systemic ventricular response to dobutamine stress in patients with mustard repair for transposition of the great arteries

Observation of the ischemic cascade in humans using contrast echocardiography during dobutamine stress.

Experimental studies have postulated the ischemic cascade and the present study was designed to elucidate whether it can be observed in the clinical setting. Fifty-three patients suspected of having coronary artery disease were studied. Myocardial perfusion abnormalities (MPA) and wall motion abnormalities (WMA) were assessed simultaneously by infusion of Levovist during dobutamine stress echocardiography. Time - intensity data of myocardial opacification were fitted for Y=A (1-e(-)(beta) (t)) from which the rate of increase (beta) of intensity were derived both at rest and during stress. Wall motion was also given a score. Bright opacification was observed in 50 patients: 25 showed significant stenosis (>50%) in the left anterior descending artery (group II) on coronary angiography and 25 did not (group I). Significant differences were found in the beta ratio (stress/rest) between the 2 groups at a low-dose (2.0+/-0.3 vs 1.5+/-0.5, p<0.05) and at a high-dose of dobutamine (2.7+/-1.0 vs 1.1+/-0.5, p<0.001), whereas the wall motion score differed only at a high-dose. Of the 25 patients in group II, MPA preceded WMA in 12, both occurred at the same stage in 12, and neither MPA nor WMA was seen in 1. These data prove the ischemic cascade clinically, using contrast echocardiography, by demonstrating that MPA precede WMA during dobutamine stress in patients with coronary stenosis.

Limitation of cardiac output by total isovolumic time during pharmacologic stress in patients with dilated cardiomyopathy: Activation-mediated effects of leftbundle branch block and coronary artery disease

ObjectivesWe sought to separate the effects of associated left bundle branch block (LBBB) and coronary artery disease (CAD) on peak cardiac output (CO) during dobutamine stress in patients with dilated cardiomyopathy (DCM). BackgroundThe mechanisms limiting CO during stress in patients with DCM are unclear. Both LBBB and CAD may do so by prolonging the total isovolumic time (t-IVT). MethodsA total of 59 patients with DCM—34 with CAD (20 normal activation [NA], 14 LBBB) and 25 without CAD (15 NA, 10 LBBB)—were studied. The total IVT (s/min; calculated as: 60 − [total ejection time+ total filling time] ) and CO were measured by Doppler echocardiography. ResultsAt rest, t-IVT was 8 s/min longer with LBBB (p < 0.001), was unaffected by CAD, and did not correlate with rest CO. During stress, CO correlated with t-IVT (r = −0.73, p < 0.001) in all four patient groups. In the absence of CAD, t-IVT became shortened (NA by 7 ± 3 s/min; LBBB by 9 ± 4 s/min) and correlated with a fall in the QRS duration (NA: r = 0.87; LBBB: r = 0.91), and CO increased with stress (NA by 4.7 ± 2.7 l/min; LBBB by 4.0 ± 2.3 l/min; all p < 0.001). With CAD, t-IVT did not shorten normally with stress. Instead, t-IVT was 5.6 s/min longer and CO was 3.3 l/min lower than in those without CAD (both p < 0.001), and t-IVT did not correlate with the QRS duration. ConclusionsIn patients with DCM, t-IVT during pharmacologic stress depends on changes in ventricular activation induced by LBBB or CAD and is, by itself, a major determinant of peak CO during stress.

Early systolic mitral annular motion velocities responses to dobutamine infusion predict myocardial viability in patients with previous myocardial infarction

Objective This study was undertaken for the determination of the correlation between myocardial viability and regional systolic mitral annular motion velocity (MAV) response to dobutamine stress in patients with previous myocardial infarction (MI) with pulsed tissue Doppler scan imaging. Methods The study included 45 patients (mean age, 65 ± 12 years) with previous MI with 1 major coronary lesion and 30 healthy individuals (mean age, 61 ± 14 years). 99mTc-methoxyisobutylisonitrile scintigraphy was performed to divide the patients into 2 groups: the viability (+) group (n = 25) and the viability (−) group (n = 20). Dobutamine was infused (at 2, 5, 10, and 20 μg/kg/min), and the peak first and second systolic MAVs (Sw1 and Sw2, respectively) were measured at the level of the mitral annulus corresponding to the infarct regions in the MI group and to the 6 mitral annular sites in the control group. In addition, the left ventricular wall motion score index (WMSI) was determined with 2-dimensional echocardiography. Results At baseline, the WMSI was significantly greater and the mean Sw1 and Sw2 were significantly lower in both the viability (+) and (−) groups than in the control group, but there were no significant differences between the viability (+) and (−) groups. After dobutamine infusion, the WMSI improved only in the viability (+) group. The mean Sw1 and Sw2 increased significantly with 2 μg/kg/min and 5 μg/kg/min of dobutamine, respectively, in the viability (+) group. With an increase in Sw1 of 2.0 cm/s or more with 5 μg/kg/min of dobutamine, viable myocardium was detected, with a sensitivity of 92% and a specificity of 90%. There were no significant increases in Sw1 or Sw2 in the viability (−) group with dobutamine infusion. Conclusion Viable left ventricular myocardium is identified with peak early systolic MAV during dobutamine infusion. (Am Heart J 2002;143:552-8.)

Influence of left ventricular size and hemodynamics on the systolic longitudinal myocardial Doppler velocity response to stress

Background Systolic myocardial Doppler velocity accurately identifies coronary artery disease. However, these velocities may be affected by age, hemodynamic responses to stress, and left ventricular cavity size. We sought to examine the influences of these variables on myocardial velocity during dobutamine stress in patients with normal wall motion. Methods One hundred seventy-nine consecutive patients with normal dobutamine echocardiograms were studied. Color myocardial tissue Doppler data were obtained at rest and peak stress, and peak systolic myocardial velocity (PSV) was measured in all basal and midventricular segments. Velocities at rest and peak stress were compared with left ventricular diastolic and systolic volumes, blood pressure, heart rate, and age by Pearson correlation and interdecile analysis by use of analysis of variance. Results The only clinical variable correlating with velocity was age; PSV showed only mild correlation with age at rest (r2 = 0.01, P =.001) and peak stress (r2 = 0.02, P =.001), but the normal peak velocity was significantly different between the extremes of age (<44 years and >74 years). There was very weak correlation of PSV with systolic and diastolic blood pressure (r2 < 0.01), heart rate (r2 < 0.01), systemic vascular resistance (r2 = 0.08), and left ventricular volumes (r2 < 0.01). Conclusions Peak systolic velocity during dobutamine stress is relatively independent of hemodynamic factors and left ventricular cavity size. The extremes of age may influence peak systolic Doppler velocities. These results suggest that peak systolic velocity may be a robust quantitative measure during dobutamine echocardiography across most patient subgroups. (Am Heart J 2002;143:169-75.)

Left ventricular systolic dysfunction during exercise and dobutamine stress in patients with hypertrophic cardiomyopathy

OBJECTIVESWe sought to characterize stress-induced left ventricular systolic dysfunction in patients with hypertrophic cardiomyopathy (HCM).BACKGROUNDMyocardial ischemia and diastolic dysfunction occur in patients with HCM. We hypothesized that, in the setting of transient myocardial ischemia, left ventricular systolic dysfunction occurs during exercise and dobutamine stress.METHODSWe studied 39 patients with HCM but without obstructive symptoms at rest or coronary artery disease. A continuous ventricular function monitor equipped with cadmium telluride detectors (VEST) was used to evaluate left ventricular function during supine bicycle ergometer exercise. Dobutamine stress echocardiography (DSE) was also performed. The left ventricular ejection fraction (LVEF) and regional wall motion were determined from echocardiographic images.RESULTSChanges in the LVEF correlated between exercise and dobutamine stress (r = 0.643, p < 0.0001). The LVEF decreased more than 5% at peak exercise in 17 of patients (group II), while the other patients had normal responses (group I). New regional wall motion abnormalities during dobutamine infusion were detected in 18 of 110 (16.4%) segments in group I and 42 of 85 (49.4%) segments in group II. Decreased or unchanged regional wall motion occurred more frequently in hypertrophied segments than in nonhypertrophied segments (p < 0.0001). There were significant inverse correlations between the LVEF responses during both stresses and the number of abnormal segments noted during dobutamine stress in all patients (VEST: p < 0.005; DSE: p < 0.0005). Signs of left ventricular obstruction were observed in 11 of 39 patients during DSE. However, there was no significant correlation between the LVEF response and the dobutamine-induced left ventricular pressure gradient.CONCLUSIONSExercise-induced systolic dysfunction occurred in 50% of patients with HCM. In these patients, regional wall motion abnormalities were present in hypertrophied segments.

Dobutamine stress: Effects on regional myocardial blood flow and wall motion

This investigation studied the relation between regional myocardial blood flow and left ventricular function during dobutamine stress in patients with coronary artery disease. Dobutamine stress is becoming more frequently used as an alternative to dynamic exercise in patients with ischemic heart disease. We studied 12 patients with coronary artery disease. Dobutamine was infused from 5 micrograms/kg body weight per min up to 40 micrograms/kg per min or until chest pain or other intolerable side effects. Regional myocardial blood flow was measured with positron emission tomography and oxygen-15-labeled water. Regional wall motion was assessed in three short-axis slices by magnetic resonance imaging. Each slice was subdivided into four regions: septal, anterior, lateral and inferior. A total of 140 regions were suitable for comparison. During stress, new wall motion abnormalities developed in 27 regions. Myocardial blood flow (mean +/- SD) increased in 113 regions that did not develop wall motion abnormalities (0.98 +/- 0.26 [baseline] vs. 1.98 +/- 0.87 [dobutamine] ml/min per g, p < 0.001), whereas it did not change significantly in regions with stress-induced wall motion abnormalities (1.00 +/- 0.28 [baseline] vs. 1.30 +/- 0.62 [dobutamine] ml/min per g, p = NS). An absolute decrease in myocardial blood flow below the value at rest was observed in seven segments that developed wall motion abnormalities during stress. The normal functional response to dobutamine stress is paralleled by an increase in coronary flow, whereas mechanical dysfunction is accompanied by a blunted increase, or even a paradoxic decrease, in regional coronary flow.