Low-dose Dobutamine Stress Research Articles

Preclinical cardiac dysfunction in transfusion-dependent children and young adults detected with low-dose dobutamine stress echocardiography

Transfusion-dependent (TD) patients develop cardiac iron overload that will eventually lead to cardiac pump failure. Low-dose dobutamine stress echocardiography may complement resting echocardiography and identify preclinical myocardial dysfunction caused by early cardiac hemosiderosis. Twenty-six iron-overloaded TD patients had stress echocardiography with 5 μg/kg per minute of dobutamine. Indexed left ventricular (LV) mass, LV dimensions, meridional wall stress, and cardiac index were significantly increased. TD patients had similar LV shortening fraction by M-mode (40.5% ± 5.6% vs 39.4% ± 4.5%) but had a lower mean LV ejection fraction (53.3% ± 3.9% vs 46.8% ± 6.9%, P < .002) and a subnormal increase in cardiac index during dobutamine stress (35% ± 20% vs 11% ± 16%, P < .0001). Impairment in LV relaxation was demonstrated by a prolonged isovolumetric relaxation time (0.060 ± 0.005 vs 0.088 ± 0.019 seconds, P < .0001), increased peak mitral E wave, and abnormal E/A ratio. Asymptomatic TD patients demonstrate decreased systolic functional reserve and abnormal left ventricular relaxation that may be caused by cardiac hemosiderosis. Low-dose dobutamine stress echocardiography may be useful for detecting and following cardiac dysfunction in patients at risk for cardiac hemosiderosis. (J Am Soc Echocardiogr 1998;11:948-56.)

Prognostic value of myocardial viability in medically treated patients with global left ventricular dysfunction early after an acute uncomplicated myocardial infarction: a dobutamine stress echocardiographic study.

Residual viable myocardium identified by dobutamine stress after myocardial infarction may act as an unstable substrate for further events such as subsequent angina and reinfarction. However, in patients with severe global left ventricular dysfunction, viability might be protective rather than detrimental. The aim of this study was to assess the impact on survival of echocardiographically detected viability in medically treated patients with global left ventricular dysfunction evaluated after acute uncomplicated myocardial infarction. The data bank of the large-scale, prospective, multicenter, observational Echo Dobutamine International Cooperative (EDIC) study was interrogated to select 314 medically treated patients (271 men; age, 58+/-9 years) who underwent low-dose (</=10 microg x kg-1 x min-1) dobutamine for the detection of myocardial viability and high-dose dobutamine for the detection of myocardial ischemia (</=40 microg x kg-1 x min-1 with atropine </=1 mg) performed 12+/-6 days after an acute uncomplicated myocardial infarction and showing a moderate to severe resting left ventricular dysfunction (wall motion score index [WMSI] >1.6). Patients were followed up for 9+/-7 months. Low-dose dobutamine stress echocardiography identified myocardial viability in 130 patients (52%). Dobutamine-atropine stress echocardiography was positive for ischemia in 148 patients (47%) and negative in 166 patients (53%). During the follow-up, there were 12 cardiac deaths (3.8% of the total population). With the use of Cox proportional hazards model, delta low-dose WMSI (the variation between rest WMSI and low-dose WMSI) was shown to exert a protective effect by reducing cardiac death by 0.8 for each decrease in WMSI at low-dose dobutamine (coefficient, -0.2; hazard ratio, 0.8; P<0.03); WMSI at peak stress was the best predictor of cardiac death in this set of patients (hazard ratio, 14.9; P<0.0018). In medically treated patients with severe global left ventricular dysfunction early after acute uncomplicated myocardial infarction, the presence of myocardial viability identified as inotropic reserve after low-dose dobutamine is associated with a higher probability of survival. The higher the number of segments showing improvement of function, the better the impact is of myocardial viability on survival. The presence of inducible ischemia in this set of patients is the best predictor of cardiac death.

Change of the new left ventricular function index (TEI INDEX) in acute myocardial infarction

It is well known that restrictive transmitral flow(TMF) pattern is predictive of higher cardiac mortality in patients(pts) with chronic heart failure(CHF). However, prognostic value of non-restrictive TMF pattem(NR) in pts with CHF is still unknown. We evaluated changes in left ventdcular(LV) filling with low dose dobutamine stress echocardiography(DSE) and assessed the prognostic significance of changes of LV filling in pts with CHF showing NR. Low dose (10mcg /kg/min) DSE was performed in 45 pts(36men, age 60+11 years) with CHF(35 pts with prior myocardial infarction, 10 with dilated cardiomyopathy) in NYHA class I1-111 with a mean LVEF of 40+13%. Pts were followed over 22+7 months for cardiac events. We measured peak velocities of eady(E) and late(A) diastolic TMF. Isovotumetdc relaxation time(IRT:msec) and deceleration time(DT:msec) of TMF were also measured. We obtained LV outflow time-velocity integrals(OTI) as an index of stroke volume. Then, we evaluated the relations between the changes(A) of these variables during DSE and cardiac events. Pts were subdivided into two groups who had cardiac events(CE:16pts) and had not(NCE:29pts)during followed period. In NCE, percent& IRT shortened significantly during DSE compared to that in CE (NCE:-25% vs CE:-2.4%, p<0.01).ADT,&A/E and AOTI did no~ differ between the two groups. Multivariate analysis showed thatA IRT was the only independent predictor of cardiac events (p<0.01). Conclusions: The shortening of IRT with dobutamine was significantly related to less cardiac event in pts with CHF, suggesting that preserved lusitropy might have favorable effects on the clinical outcome in pts with CHF. Assessment of LV diastolic property with DSE might be useful to predict the outcome in pts with mild to moderate CHF.

Diastolic response during low dose dobutamine stress echocardiography is related to the outcome of patients with mild to moderate chronic heart failure

Diastolic response during low dose dobutamine stress echocardiography is related to the outcome of patients with mild to moderate chronic heart failure

Contrast enhanced and functional magnetic resonance imaging for the detection of viable myocardium after infarction

Purpose Viable myocardium after acute myocardial infarction may be characterized by magnetic resonance imaging (MRI) either by demonstration of recovery of wall motion under dobutamine stress or by perfusion patterns after contrast medium administration. This study examines the relation between the two techniques. Materials and Methods Gradient-echo MRI at rest and under low-dose dobutamine stress was performed in 28 patients within the first 2 weeks after acute myocardial infarction. In addition, spin-echo MRI was performed after gadolinium-DOTA administration. Wall motion at rest and under stress was scored to assess the contractile reserve of the infarct regions. Infarct enhancement patterns were classified as subendocardial, transmural, or as a doughnut pattern. Result Subendocardial or absent infarct enhancement was related to functional recovery under stress in 31 of 37 infarct segments. Transmural infarct enhancement was correlated with the absence of functional recovery in 10 of 17 infarct segments (p < 0.002), indicating nonviability. The doughnut pattern was exclusively associated with the absence of viability (five of five). Conclusion Contrast enhancement patterns are related to residual myocardial viability. (Am Heart J 1998:135:875-80.)

Low Dose Dobutamine Echocardiography Predicts Improvement in Functional Capacity After Exercise Training in Patients With Ischemic Cardiomyopathy: Prognostic Implication

Objectives. This study sought to investigate whether the identification of hibernating myocardium by low dose dobutamine stress echocardiography (LDSE) may predict an improvement in functional capacity after moderate exercise training in patients with ischemic cardiomyopathy. Another objective was to assess whether exercise training may affect the outcome.Background. There is evidence that exercise training improves left ventricular (LV) function as well as functional capacity in patients with a previous myocardial infarction and LV dysfunction. We hypothesized that the magnitude of these improvements might be related to the extent of hibernating myocardium.Methods. We studied 71 consecutive patients 56 ± 9 years old (mean ± SD) with chronic heart failure secondary to ischemic cardiomyopathy (LV ejection fraction [LVEF] <40%). All patients were in sinus rhythm and were clinically stable during the previous 3 months. Patients were randomized into two matched groups. Group T (n = 36) underwent exercise training at 60% of peak oxygen uptake (V̇o2) three times a week for 10 weeks. Group C (n = 35) did not exercise. At study entry and end, all patients underwent an exercise test with gas exchange analysis and LDSE (5 to 20 μg/kg body weight per min).Results. At baseline, a positive contractile response (CS+) to LDSE was observed in 317 of 576 segments in group T and 291 of 560 segments in group C. After 10 weeks, peak V̇o2and peak work rate increased only in trained patients (peak V̇o2: from 16.2 ± 3 to 20.8 ± 4 ml/kg per min; work capacity: from 108 ± 20 to 131 ± 25 W, p < 0.001 vs. group C for both). The presence of CS+ at baseline was associated with a sensitivity of 70% and a specificity of 77% for predicting an increase in the functional capacity after exercise training. Positive and negative predictive values of LDSE were 84% and 59%, respectively. Independent predictors of cardiac events were a pre-to-posttraining difference in LVEF at peak dobutamine infusion and the presence of a viable response at baseline (p = 0.004 and 0.008, respectively). The log-rank test demonstrated that trained patients had a significantly lower probability of cardiac events during follow-up than sedentary control patients (p < 0.001).Conclusions. The presence of hibernating myocardium as assessed by LDSE predicts the magnitude of improvement in functional capacity after moderate exercise training in patients with chronic heart failure. A significant increase in functional capacity after exercise training is associated with a lower incidence of cardiac events during follow-up.

Low-Dose Dobutamine Stress Echocardiography in Children and Young Adults

Dobutamine stress echocardiography has become widely accepted in the evaluation of adult patients with coronary heart disease. We wanted to assess the feasibility and the physiologic responses of stress echocardiography at low doses of dobutamine in a population of normal children and adults. Once achieved, we submitted a group of post-anthracycline patients to the test to assess the sensitivity of low-dose dobutamine stress echocardiography in the detection of cardiac dysfunction. Thirty-two healthy children and young adults (19 male and 13 female subjects, median age 15 years [range 6 to 26]) were studied. After the initial study of normal subjects, we submitted a cohort of 39 patients (18 female and 21 male, aged 6 to 25 years), who completed anthracycline chemotherapy, to the same protocol. Dobutamine was infused at rates of 0.5 to 2.5 and 5 μg/kg/min and echocardiographic measurements were obtained at rest and at the end of each stage. The test could be completed in 100% of the subjects without major complications. Statistically significant differences between resting echocardiographic values of systolic and diastolic function and values at 2.5 and 5 μg/kg/min of dobutamine were found. Moreover, dobutamine revealed or enhanced differences between normal subjects and the post-anthracycline patients. Thus, low-dose dobutamine stress echocardiography is feasible and safe in older children. The test is very sensitive for the detection of subclinical cardiac dysfunction in post-anthracycline patients and could possibly assess functional myocardial reserve.

Perioperative transoesophageal echocardiography with low-dose dobutamine stress for evaluation of myocardial viability: a feasible approach?

The feasibility of low-dose dobutamine stress combined with transoesophageal echocardiography (TEE) to detect viable left ventricular myocardium was evaluated in 22 anaesthetised patients prior to sternotomy for elective coronary artery bypass grafting (CABG). After baseline measurements, a dobutamine infusion beginning with 5 micrograms.kg-1.min-1 was started and eventually increased to 10 micrograms.kg-1.min-1. Viability was assessed as visual improvement of left ventricular wall motion (LVWM). The criteria for discontinuation of the infusion were: 1. any changes in LVWM, 2. an increase in preanaesthetic blood pressure exceeding 40 mmHg, and/or a > 20% increase in preanaesthetic heart rate compared to preanaesthetic levels. An off-line evaluation of LVWM was based upon visualisation of the left ventricle in a transgastric short-axis mid-papillary (mid-P) view, and the left ventricle was divided into anterior, septal, inferior, and lateral segments. Moreover, an off-line semiautomatic analysing system was used for assessing regional and global LVWM. With this analysis the effects on LVWM from changes in preload and afterload could be addressed. 19 patients showed a decreased LVWM in one or several segments at baseline. A total of 36 segments exhibited decreased LVWM (an average of 1.9 segments/patient). Of these, 22 segments (61%) improved with dobutamine, while 12 segments (33%) did not, and 2 (6%) became more dysfunctional. Another 6 segments with normal motion at baseline became dysfunctional with dobutamine. According to the off-line semiautomatic analysing system for LVWM, there were no statistically significant changes with dobutamine stimulation. Only one patient showed an increased postoperative aspartateaminotransferase (ASAT) value (3.0 mmol.l-1) but no ECG changes. Since we regard the visual assessment of LVWM as being more applicable for this protocol than the semiautomatic analysis, we conclude that low-dose dobutamine stress echocardiography seems to be a feasible method for detecting viable myocardium in the anaesthetised patient scheduled for elective CABG surgery. However, the semiautomatic analysis complemented our findings, since the variations in pre- and afterload did not significantly change the size of the left ventricle, which hereby would imply LVWM changes.

Prognostic value of residual ischaemia assessed by exercise electrocardiography and dobutamine stress echocardiography in low-risk patients following acute myocardial infarction.

Risk stratification after uncomplicated myocardial infarction is major clinical problem. In particular, the prognostic value of residual inducible ischaemia is still controversial. We compared the relative prognostic value of exercise ECG and dobutamine stress echocardiography performed in the early post-infarction period. Four hundred and six patients (53 female) aged 57 +/- 9 years, undergoing maximal exercise ECG and dobutamine stress echocardiography within 10 days of an uncomplicated myocardial infarction off therapy, were prospectively followed-up for 8.8 months. Age, sex, diabetes, smoking habit, hypertension, dyslipidaemia, infarct location, thrombolysis and resting wall motion score index were taken into account among clinical variables. Prognostic correlations were made vs spontaneous events (cardiac death, non-fatal reinfarction and unstable angina requiring hospitalization) whilst patients undergoing revascularization (by means of percutaneous transluminal coronary angioplasty or coronary artery bypass surgery) at the time of the procedure were censored. One hundred and twenty-seven events occurred during the follow-up: 41 (10%) were spontaneous (five deaths, 12 reinfarctions and 24 unstable angina) and 86 procedural (27 angioplasty and 59 bypass surgery). Spontaneous events were not predicted by any clinical, exercise ECG or dobutamine stress echocardiography variable, but the negative predictive value of both tests was excellent (91% and 90% respectively). With a multivariate Cox analysis, male gender, positive low-workload (< 100 W) exercise ECG (P < 0.0001), positive low-dose dobutamine stress echocardiography (P < 0.0001) and rest-stress wall motion score index variation (P < 0.001) were found to predict cumulative cardiac events with an independent and additive value. Dobutamine stress echocardiography was significantly more sensitive (P < 0.05) and less specific (P < 0.01) in predicting the outcome of patients with anterior infarction, whilst exercise ECG was significantly more sensitive (P < 0.05) in patients with non-Q wave infarction. (1) Spontaneous events are poorly predicted by provocative tests in low-risk patients after uncomplicated myocardial infarction. (2) However, both exercise ECG and dobutamine stress echocardiography can predict a favourable outcome with a very high negative predictive value. (3) Dobutamine stress echocardiography should be considered a secondary option in cases where the exercise ECG is equivocal or when the location of ischaemia is a relevant issue. (4) The possibility that the two tests have a differential utility depending on the infarct location and type (Q wave vs non-Q wave) may be clinically relevant and deserves further evaluation.

Left ventricular function under low-dose dobutamine stress in diabetic patients with myocardial perfusion defects: An assessment with radionuclide angiography

Left ventricular function under low-dose dobutamine stress in diabetic patients with myocardial perfusion defects: An assessment with radionuclide angiography

The Contribution of the Left Atrioventricular Plane Displacement During Low Dose Dobutamine Stress Echocardiography in Predicting Recovery of Left Ventricular Dyssynergies.

The aim of this study was to assess the significance of the left systolic atrioventricular (AV) plane displacement during low dose dobutamine stress echocardiography (DSE), in predicting the recovery of left ventricular dyssynergies after revascularization. In 30 infarctiers with left ventricular dysfunction scheduled for RE (14 percutaneous transluminal coronary angioplasty and 16 coronary artery bypass graft) and in 25 age- and sex-matched healthy subjects, a DSE, using a 16 ventricular segment model and a four-grade scoring system for the assessment of regional wall motion of the left ventricle was performed. Prior and during DSE, the left systolic AV plane displacement was recorded from the apical four- and two-chamber views, by M-mode echo, at four left ventricular sites, corresponding to the septal, lateral, anterior, and inferior walls, both in patients and controls. The study was repeated in all patients 101 +/- 14 days after successful revascularization. Healthy subjects showed a significant increase of left systolic AV plane displacement at all left ventricular sites during dobutamine infusion (DI) (P < 0.001). Patients also exhibited a significant maximum increase of left systolic AV plane displacement during DSE only in the dyssynergic sites with functional improvement in the postrevascularization echocardiogram (P < 0.001). In the remaining dyssynergic sites, without functional improvement after revascularization, the left systolic AV plane displacement did not change (P > 0.05). Selecting a maximum LAVPD increase of >2 mm at any site of the left ventricule to predict recovery of the regional ventricular dyssynergies, results in a sensitivity of 91%, specificity of 83%, positive predictive value of 88%, and negative predictive value of 87%. When two-dimensional DSE was used for the detection of reversible dysfunction, sensitivity and specificity were found to be 81.5% and 87.5%, respectively, while the positive and negative predictive values were 90% and 78%, respectively. When the two methods were in agreement the sensitivity was 90%, the specificity 100%, and the positive and negative predictive values were 100% and 84.2%, respectively. The assessment of left systolic AV plane displacement during DI constitutes a new, simple, and accurate method in the prediction of left ventricular dyssynergy recovery after revascularization. The combination of this method and two-dimensional DSE are basic predictor markers of viability of dysfunctional myocardium. (ECHOCARDIOGRAPHY, Volume 13, November 1996)

Comparative study of rest technetium-99m sestamibi SPET and low-dose dobutamine stress echocardiography for the early assessment of myocardial viability after acute myocardial infarction: importance of the severity of the infarct-related stenosis

Rest technetium-99m sestamibi single-photon emission tomography (SPET) has been shown to underestimate viability in some patients with chronic ischaemic myocardial dysfunction. The present study was designed to appraise the value of 99mTc-sestamibi as a viability tracer in patients with a recent myocardial infarction and to determine factors that might influence its accuracy in assessing infarct size. Therefore, rest 99mTc-sestamibi SPET, low-dose dobutamines stress echocardiography and quantitative coronary angiography were performed in 51 patients with a recent myocardial infarction. Perfusion activity and regional wall motion were scored semi-quantitatively using the same segmental division of the left ventricle. Assessment of 99mTc-sestamibi uptake as a marker of viability was performed by comparing a binary uptake score (viable=>50% vs necrotic =</=50% of the maximal tracer activity) with a binary wall motion classification during low-dose dobutamine infusion (viable=normal/hypokinetic vs necrotic=akinetic/dyskinetic). Infarct size, expressed as the number of segments with evidence of necrotic tissue, was significantly greater in the scintigraphic study than in the echocardiographic study (2.8+/-1.5 vs 2.2+/-1.3, P=0.006). This overestimation of infarct size by 99mTc-sestamibi was present only in patients with a severe infarct-related stenosis (% diameter stenosis >/=65%-100%) and particularly those with "late" reperfusion therapy (time delay >/=180 min). In patients without a severe infarct-related stenosis, 99mTc-sestamibi was able to accurately distinguish viable from necrotic segments. Thus, rest 99mTc-sestamibi scintigraphy early after acute myocardial infarction may underestimate residual viability within the infarct region, particularly in patients with low flow state coronary anatomy, as a result of a severe infarct-related stenosis and/or late reperfusion therapy.

Low-dose dobutamine echocardiography and rest-redistribution thallium-201 tomography in the assessment of spontaneous recovery of left ventricular function after recent myocardial infarction

Spontaneous improvement of contraction and perfusion occurs after acute myocardial infarction. The relative merit of low-dose dobutamine stress echocardiography (LDDE) and rest-redistribution thallium scintigraphy (RR TI) in this setting has not been evaluated. We studied 30 patients at 7 ± 3 days after acute myocardial infarction with LDDE (5 to 10 μg/kg/min) and RR TI single photon emission computed tomography. Viability was defined as improvement of wall thickening at LDDE in the presence of redistribution or a defect with uptake ≥50% of peak activity at RR TI. Baseline echocardiography and RR TI were repeated after 3 months. In 112 dyssynergic segments, viability was detected in 60 (54%) by RR TI and in 39 (35%) by LDDE ( p < 0.005). Spontaneous improvement of function was detected in 35 (31%) segments. In the same regions, thallium uptake increased significantly. The sensitivity, specificity, and accuracy of LDDE for predicting late improvement of wall motion were 77%, 84%, and 82%, respectively. Those of RR TI were 77%, 57%, and 63%, respectively. Specificity and accuracy of LDDE were higher than RR TI ( p < 0.005). We conclude that a myocardial viability pattern after acute myocardial infarction is more frequently detected by RR TI than by LDDE. Both techniques are equally sensitive, but LDDE is a more specific predictor of spontaneous recovery of regional left ventricular function.

Low dose dobutamine stress echocardiography can predict improvement in left ventricular ejection fraction after revascularization

Low dose dobutamine stress echocardiography can predict improvement in left ventricular ejection fraction after revascularization

Usefulness of Low Dose Dobutamine Stress Echocardiography in Patients with Acute Myocardial Infarction

Usefulness of Low Dose Dobutamine Stress Echocardiography in Patients with Acute Myocardial Infarction

Myocardial Velocity Gradient during Low-dose Dobutamine Stress Echocardiography in the Predietion of viable Myoeardium in the Infarct Zone

Myocardial Velocity Gradient during Low-dose Dobutamine Stress Echocardiography in the Predietion of viable Myoeardium in the Infarct Zone

Prediction of Improvement of Ventricular Function after First Acute Myocardial Infarction Using Low-Dose Dobutamine Stress Echocardiography

Prediction of Improvement of Ventricular Function after First Acute Myocardial Infarction Using Low-Dose Dobutamine Stress Echocardiography

Does myocardial viability detected by low-dose dobutamine stress echocardiography identify patients following acute myocardial infarction who's left ventricular regional function recovers after revascularization?

Does myocardial viability detected by low-dose dobutamine stress echocardiography identify patients following acute myocardial infarction who's left ventricular regional function recovers after revascularization?

T-Wave normalization during dobutamine echocardiography for diagnosis of viable myocardium

These preliminary data indicate that T-wave normalization during low-dose dobutamine stress testing is an ancillary sign of viable myocardium after acute myocardial infarction and increases the sensitivity of echocardiography for predicting late spontaneous recovery of function.

722-3 Low Dose Dobutamine Predicts Recovery of Global but not Regional Left Ventricular Function After Revascularlzatlon In Patients with Chronic Ischemic Dysfunction

The purpose of this study was to evaluate the ability of low dose (LD) dobutamine stress echocardiography (DSE) to independently predict recovery of global and regional left ventricular (LV) function following coronary artery bypass surgery (CABG) in patients with ischemic LV dysfunction. Sixteen patients with multivessel coronary artery disease and reduced ejection fraction (EF = 0.25 ± 0.08) underwent DSE prior to CABG, and 2D echo at 20 ± 17 weeks post-CABG (FlU). Global EF was measured at baseline, LD and at F/U; improvement was defined as an increase in EF of &gt; 0.05. Global EF at F/U improved in 11/16 pts (69%). All 11 (100%) pts had improvement in EF on LD DSE. Improvement in regional function was assessed in segments (segs) that were akinetic (AK) or severely hypokinetic (SHK) at baseline. Of 147 SHK/AK segs at baseline, 27 (18%) had LD augmentation; of these 27 segs, 13 (48%) improved on FlU. Of 120 SHK/AK which did not augment at LD, 34 (28%) improved at F/U. The sensitivity (SENSI). specificity (SPECI), positive (PPV) and negative predictive values (NPV) of LD augmentation for predicting improvement in regional and global LV function were: SENSI SPECI PPV NPV p Regional 38% 86% 48% 72% * 0.05 * Global 100% 60% 85% ‡ 100% 0.02 ‡ 1) Improvement in EF during LD DSE predicts recovery of global LV function with a PPV of 85%, and 2) Failure of individual AK or SHK segments to improve with LD DSE predicts lack of recovery at F/U with a NPV of 72%. Low dose dobutamine stress echocardiography can therefore be used to predict recovery of global function and lack of recovery of regional ventricularfunction following revascularization in patients with chronic ischemic dysfunction. It may be of relative greater value in predicting global as compa red to regional function.