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Background: Akinesis becoming dyskinesis (AKBD) at high-dose dobutamine stress echocardiography (DSE) has been disregarded as a marker of myocardial ischemia. However, its prognostic significance is unknown., Objectives: We sought to assess the long-term outcome of patients with AKBD during DSE., Methods: A total of 731 patients (age 62 +/- 15 years, 628 men) with two or more akinetic left ventricular segments at rest underwent DSE and were followed up for a mean period of 5 +/- 2.7 years. The end points considered during follow-up were hard cardiac events (cardiac death and nonfatal myocardial infarction) and heart failure., Results: Dyskinesis in two or more segments at peak stress developed in 60 patients (8%). Resting wall-motion score index was 2.6 +/- 0.56 in patients with AKBD versus 2.3 +/- 0.55 in patients without AKBD (P = .0002). Ischemia occurred in 197 patients (27%). During follow-up, 254 patients (35%) developed hard cardiac events and 204 patients (28%) developed heart failure. In all, 226 patients (31%) died of various causes (cardiac death in 172 patients). The annualized hard cardiac event rate was 11% in patients with AKBD and 6% in patients without (P = .03). The incidence of heart failure was significantly higher in patients with AKBD than without (47% vs 26%, P < .001). Independent predictors of hard cardiac events were age (hazard ratio [HR] 1.03 [confidence interval {CI} = 1.01-1.04]), previous myocardial infarction (HR 1.4 [CI = 1.1-1.9]), diabetes mellitus (HR 1.8 [CI = 1.3-2.5]), resting wall-motion score index (HR 1.11 [CI = 1.01-1.04]), and AKBD (HR 1.6 [CI = 1.1-2.4])., Conclusion: AKBD at peak DSE is associated with increased risk of cardiac events in patients with akinetic segments at baseline echocardiogram.

Currently, there are no outcome data to suggest an incremental value of stress echocardiography in the risk stratification of patients who have hypertension after controlling for the left ventricular mass index (LVMI). This study assessed the incremental value of dobutamine stress echocardiography (DSE) for the prediction of mortality rate and cardiac events in patients who have hypertension. We studied 596 patients who had hypertension (mean age 62 +/- 12 years; 382 men) and who underwent DSE for evaluation of known or suspected coronary artery disease. End points during follow-up were hard cardiac events (cardiac death and nonfatal myocardial infarction) and total mortality rate. Left ventricular hypertrophy was detected by echocardiography in 119 patients (20%). During a median follow-up of 3 years, 101 patients (17%) died (43 cardiac deaths) and 19 patients had nonfatal myocardial infarction. In an incremental multivariate analysis model, clinical predictors of hard cardiac events were age, history of congestive heart failure, and LVMI. The percentage of abnormal myocardial segments examined with DSE was incremental to the clinical model (chi square 41 vs 27, p <0.001). Clinical predictors of total mortality rate were age, smoking, hypercholesterolemia, history of congestive heart failure, and LVMI. The peak wall motion score index was incremental to the clinical model (chi square 45 vs 40, p <0.05). DSE provides incremental data for the prediction of mortality rate and hard cardiac events in patients who have hypertension after adjustment for clinical data and LVMI.

Patients with normal dobutamine stress echocardiography (DSE) were shown to have a favorable outcome at an intermediate-term follow-up. However, there are scarce data regarding long-term survival after normal DSE. This study sought to assess the long-term outcome after normal DSE. We studied 401 patients (age 62 +/- 10 years, 264 men) who had a normal echocardiogram at rest and with high-dose dobutamine stress. End points during a mean follow-up of 5 +/- 1.7 years (minimum 3.5) were all-cause mortality and hard cardiac events (cardiac death and nonfatal myocardial infarction). During follow-up, 45 patients (11%) died due to various causes (cardiac death in 10 patients). Thirteen patients had nonfatal myocardial infarction (a total of 23 hard cardiac events). The annual mortality rate was 2% in the first 3 years and 2.4% between the fourth and sixth years. The annual hard cardiac event rate was 0.8% in the first 3 years and 1.7% between the fourth and sixth years. Predictors of mortality in a multivariate analysis model were advanced age (hazard ratio 1.2, 95% confidence interval CI 1.1 to 1.4) and higher heart rate at rest (hazard ratio 0.92, 95% confidence interval 0.85 to 0.99). Patients with normal DSE had excellent outcomes during the 3 years after the study. The cardiac event rate was higher between the fourth and sixth year; therefore, it may be useful to repeat the study after 3 years to reassess risk status.

Objective: The aim of this study was to assess the incremental value of dobutamine stress echocardiography (DSE) for the risk stratification of diabetic patients who are unable to perform an adequate exercise stress test. Exercise capacity is frequently impaired in patients with diabetes. The role of pharmacologic stress echocardiography in the risk stratification of diabetic patients has not been well defined., Research Design and Methods: We studied 396 diabetic patients (mean age 61 +/- 11 years, 252 men [64%]) with limited exercise capacity who underwent DSE for evaluation of known or suspected coronary artery disease (CAD). End points were hard cardiac events (cardiac death and nonfatal myocardial infarction) and all causes of mortality., Results: During a median follow-up of 3 years, 97 patients (24%) died (55 cardiac deaths), and 27 patients had nonfatal myocardial infarction. In an incremental multivariate analysis model, clinical predictors of hard cardiac events were history of congestive heart failure, previous myocardial infarction, hypercholesterolemia, and ejection fraction at rest. The percentage of ischemic segments was incremental to the clinical model in the prediction of hard cardiac events (chi(2) = 37 vs. 18, P < 0.05). Clinical predictors of all causes of mortality were history of congestive heart failure, age, hypercholesterolemia, and ejection fraction at rest. Wall motion score index at peak stress was incremental to the clinical model in the prediction of mortality (chi(2) = 52 vs. 43, P < 0.05)., Conclusions: DSE provides incremental data for the prediction of mortality and hard cardiac events in patients with diabetes who are unable to perform an adequate exercise stress test.

Unlabelled: Because of damage to cardiomyocytes and the contractile apparatus, contractile reserve may be observed less frequently in hibernating than in stunned myocardium. The aim of this study was to assess the presence of contractile reserve in response to dobutamine infusion in a large group of patients with stunned and hibernating myocardium., Methods: A total of 198 consecutive patients with ischemic cardiomyopathy (left ventricular ejection fraction < or = 40%) underwent resting 2-dimensional echocardiography to assess regional contractile dysfunction. On the basis of assessment of perfusion (with (99m)Tc-tetrofosmin SPECT) and glucose use (with (18)F-FDG SPECT), dysfunctional segments were grouped. Dysfunctional segments with normal perfusion were classified as stunned. Dysfunctional segments with a perfusion defect were classified as hibernating when a perfusion-(18)F-FDG mismatch was present. Dysfunctional segments with a perfusion defect were classified as scar tissue when a perfusion-(18)F-FDG match was present; these segments were subdivided into nontransmural and transmural scars. Contractile reserve was evaluated by dobutamine stress echocardiography., Results: Dobutamine-induced contractile reserve was more frequently found in stunned than in hibernating myocardium (61% vs. 51%, respectively; P < 0.01). Only 14% of the scarred segments improved in wall motion during dobutamine infusion, significantly less than stunned or hibernating myocardium (P < 0.001). Nontransmural scars exhibited contractile reserve more frequently than did transmural scars., Conclusion: The progressive reduction of contractile reserve in stunned, hibernating, and scarred myocardium supports the hypothesis that stunning, hibernation, and scarring are not circumscript pathophysiologic entities but represent gradual ultrastructural damage on the myocyte level.

Objective: To determine whether, compared with fundamental imaging, second harmonic imaging can improve the accuracy of dobutamine stress echocardiography for identifying viable myocardium, using nuclear imaging as a reference., Patients: 30 patients with chronic left ventricular dysfunction (mean (SD) age, 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 tomography (DISA-SPECT) with (99m)technetium-tetrofosmin/(18)F-fluorodeoxyglucose on a separate day. Myocardial viability was considered present by dobutamine stress echocardiography when segments with severe dysfunction showed a biphasic sustained improvement or an ischaemic response. Viability criteria on DISA-SPECT were normal or mildly reduced perfusion and metabolism, or perfusion/metabolism mismatch., Results: Using fundamental imaging, 330 segments showed severe dysfunction at baseline; 144 (44%) were considered viable. The agreement between dobutamine stress echocardiography by fundamental imaging and DISA-SPECT was 78%, kappa = 0.56. Using second harmonic imaging, 288 segments showed severe dysfunction; 138 (48%) were viable. The agreement between dobutamine stress echocardiography and DISA-SPECT was significantly better when second harmonic imaging was used (89%, kappa = 0.77, p = 0.001 v fundamental imaging)., Conclusions: Second harmonic imaging applied during dobutamine stress echocardiography increases the agreement with DISA-SPECT for detecting myocardial viability.

Objective: Our purpose was to assess the value of second harmonic imaging compared with fundamental imaging for the diagnosis of coronary artery disease during dobutamine stress echocardiography., Patients and Methods: Sixty-four patients underwent dobutamine stress echocardiography with both fundamental imaging and second harmonic imaging. Coronary angiography was performed within 3 months. Ischemia was defined as new or worsening wall motion abnormalities in > or = 1 segment during dobutamine stress echocardiography. Coronary artery disease was defined as a > or = 70% luminal diameter stenosis in > or = 1 coronary artery by coronary angiography., Results: There was a higher prevalence of segments with invisible border with fundamental compared with second harmonic imaging both at rest (11% vs 8%, P < .05) and at peak stress (17% vs 10%, P < .001). Significant coronary artery disease was present in 49 (77%) patients. The sensitivity of dobutamine stress echocardiography for detection of coronary artery disease by fundamental and second harmonic imaging was, respectively, 78% and 94% (P < .05), whereas specificity was similar (73% vs 73%). Second harmonic imaging had a particularly higher sensitivity for the diagnosis of 1-vessel disease (93% vs 50%, P < .05)., Conclusion: The use of second harmonic imaging improves the sensitivity of dobutamine stress echocardiography for the diagnosis of coronary artery disease compared with fundamental imaging, particularly for 1-vessel coronary artery disease, whereas specificity remains unchanged.

Background: Dobutamine myocardial perfusion imaging is a useful method for evaluation of coronary artery disease. However, this technique does not allow for ischemia monitoring, which may have an impact on the safety of the test in heart transplant recipients due to cardiac sensory denervation. The aim of this study was to assess the impact of heart transplantation on the feasibility and complications of the dobutamine stress test., Methods: We studied 225 heart transplant recipients (mean age 57 +/- 7 years) and a control group of 225 patients without previous transplant matched for age and gender by dobutamine (up to 40 microg/kg per minute) stress myocardial perfusion imaging., Results: During the test, transplant recipients had a lower prevalence of premature ventricular contractions (23% vs. 37%, p < 0.001) and ventricular tachycardia (0.04% vs 7.5%, p < 0.0001) compared with control patients. By multivariate analysis, heart transplantation was a powerful independent variable associated with a reduced risk of ventricular arrhythmias (chi(2) = 20.8, p < 0.0001) and minor side effects (nausea, dizziness, anxiety, flushing, chills) (chi(2) = 20, p < 0.0001) during dobutamine stress. The target heart rate was reached in 82% of transplant recipients and in 77% of the control group. Overall feasibility (achievement of the target heart rate and/or an ischemic end-point) was 87% in the transplant and 86% in the control group., Conclusions: Dobutamine stress myocardial perfusion imaging is a safe and feasible method for evaluation of coronary artery disease in heart transplant recipients. The prevalence of arrhythmias and minor complications using the dobutamine stress test is lower in heart transplant recipients compared with control patients. The independent association between heart transplantation and reduced risk of arrhythmias and minor side effects of the dobutamine stress test indicates that cardiac sensory and autonomic nerve function plays a major role in the induction of these complications during the test.

Background: Technetium-99m tetrofosmin single photon emission computed tomography (SPECT) imaging is increasingly used in conjunction with exercise and vasodilator stress test as a means of evaluating coronary artery disease (CAD). Dobutamine stress test is an alternative in patients with limited exercise capacity. This study assessed the accuracy of dobutamine-atropine stress tetrofosmin SPECT as a means of diagnosing and localizing CAD., Methods and Results: We studied 124 patients (mean age, 57+/-12 years; 88 men) with limited exercise capacity and suspected CAD with dobutamine (as much as 40 microg/kg/min)-atropine (as much as 1 mg) Tc-99m tetrofosmin SPECT. Resting images were acquired 24 hours after the stress test. Significant CAD was defined as 50% or greater luminal diameter stenosis in 1 or more major coronary arteries. Myocardial perfusion abnormalities (fixed and/or reversible defects) were detected in 70 of 88 patients with CAD and in 10 of the 36 patients without CAD (sensitivity = 80%, CI, 72 to 87; specificity = 72%, CI, 64 to 80; accuracy = 77%, CI, 70 to 85). Sensitivity and accuracy rates were higher by using the criterion of any defect than by using the criterion of reversible defects only (80% vs 51%, P<.0001; 77% vs 60%, P<.01, respectively). The sensitivity rate was higher in patients with multivessel CAD than in patients with single-vessel CAD (88% vs 63%, P<.05). Patients with multivessel CAD had a larger stress perfusion defect score (4.5+/-3.1 vs. 2.7+/-2.5, P<.01) than patients with single-vessel CAD., Conclusion: Dobutamine stress Tc-99m tetrofosmin SPECT is a useful method for the diagnosis and localization of CAD in patients with limited exercise capacity. Optimal accuracy of the technique is achieved by using both fixed and reversible perfusion abnormalities for the diagnosis of CAD in patients without an earlier myocardial infarction.

Background: Exercise stress myocardial perfusion scintigraphy has been used for the diagnosis of transplant coronary artery stenosis (TCAS) in cardiac allograft recipients. However, the role of pharmacologic stress myocardial perfusion imaging has not been evaluated. Aim of the study is to assess the accuracy of dobutamine stress 99m technetium tetrofosmin myocardial perfusion imaging for the diagnosis of TCAS in heart transplant recipients., Patients and Methods: We studied 50 patients (age 56 +/- 8 year, 45 men) at a mean of 6.4 +/- 2.8 years after cardiac transplant with dobutamine (up to 40 ìg/kg/min) stress 99m technetium tetrofosmin SPECT. Resting images were acquired 24 hours after the stress study. Significant TCAS was defined as > or =50% luminal diameter stenosis by coronary angiography., Results: Significant TCAS was detected in 30 patients (60%). Myocardial perfusion abnormalities (reversible and/or fixed defects) were detected in 27 of the 30 patients with and in 9 of the 20 patients without significant TCAS (sensitivity = 90%, CI 82-98, specificity = 55% CI 41-69, positive predictive value = 75%, CI 63-87, negative predictive value = 79%, CI 67-90 and accuracy = 76%, CI 64-88). Patients with multivessel TCAS had a larger stress perfusion defect score (5.6 +/- 3.1 vs 3.2 +/- 2.4, p < 0.05) compared to patients with single vessel TCAS. Among patients with abnormal perfusion who had no significant TCAS, 2 had lesions <50%, 2 had luminal irregularities and 5 had no abnormalities at angiography. Therefore specificity was 62% (8/13) in patients without any detectable angiographic abnormalities., Conclusions: Dobutamine stress tetrofosmin myocardial perfusion imaging is a highly sensitive method for the detection of TCAS in recipients of cardiac allografts. The high negative predictive value of the test indicates that patients who demonstrate normal perfusion by this method may be excluded from further invasive studies.

Background: Recent experimental studies have shown that technetium 99m methoxyisobutyl isonitrile (MIBI) underestimates flow heterogeneity induced by dobutamine and that this might have an impact on the sensitivity of dobutamine MIBI in patients with single-vessel coronary artery disease (CAD). This study compares the accuracy of dobutamine MIBI single-photon emission computed tomography (SPECT) and simultaneous echocardiography in the diagnosis of single-vessel CAD., Methods and Results: Ninety-one patients (age 57 +/- 12 years) with single-vessel CAD or without significant CAD were studied with dobutamine (up to 40 microg/kg per minute)-atropine (up to 1 mg) stress echocardiography (DSE) and simultaneous MIBI SPECT imaging. CAD was predicted on the basis of myocardial ischemia (transient wall motion abnormalities by DSE and reversible perfusion defects by MIBI). Ischemia was detected by MIBI in 30 of the 54 patients with and in 10 of the 37 patients without significant single-vessel CAD (sensitivity 56%, confidence interval [CI] 45 to 66; specificity 73%, CI 64 to 82; accuracy 63%, CI 53 to 73). Ischemia was detected by DSE in 30 patients with and in 6 patients without significant CAD (sensitivity of DSE 56%, CI 45 to 66; specificity 84%, CI 76 to 91; accuracy 67%, CI 57 to 77, P = not significant vs MIBI). For both imaging methods, sensitivity was significantly higher in patients with left anterior descending than in patients with left circumflex or right coronary artery stenosis (75% vs 40%, P <.05). The addition of echocardiography to MIBI did not improve the diagnostic accuracy (68% CI 59 to 78, P = not significant vs DSE or MIBI alone)., Conclusions: DSE and MIBI SPECT imaging have similar moderate sensitivity for the diagnosis of single-vessel CAD. Sensitivity of each of these techniques is higher in patients with left anterior descending than in patients with left circumflex or right coronary artery stenosis. There is no improvement of diagnostic accuracy by use of the combination of both techniques.