Dobutamine Echocardiography Research Articles

Early Repolarization And Ectopy During Stress Testing

PURPOSE: To examine the interaction between resting early repolarization and the occurrence of ectopy during clinical exercise testing. METHODS: Pre-stress 12-lead resting ECGs of patients presenting for the following types of stress testing were examined for evidence of early repolarization (ER): exercise ECG, nuclear exercise ECG, exercise echocardiography, dipyridamole nuclear, dobutamine nuclear and dobutamine echocardiography. Each case of ER (n=26) identified was matched with two randomly selected control patients without ER (n=52). Stress tests were performed using standard hospital protocols. The ECGs recorded before, during and after stress were examined for supraventricular (PAC) and ventricular ectopy (PVC). Ectopy was further categorized by type (uniform versus multiform PVC, isolated ectopic beats versus runs of ectopy, etc.). A chi-square test for two independent samples (2 × 2 contingency table) was used to determine if a significant interaction was present between the occurrence of resting ER and the presence of each of the following before, during and/or after stress: PAC and/or PVC, PAC only, PVC only, multiform PVC, and PVC runs. RESULTS: The proportions of the sample exhibiting and not exhibiting ectopy before, during and/or after stress did not differ significantly between patients with and without evidence of ER on resting ECG. That is, there were no significant (p>0.05) interactions between the occurrence of ER and the presence of ectopy. CONCLUSIONS: The presence of ER on the resting ECG does not appear to be indicative of ectopy during clinical stress testing.

Clinical Assessment and Rest and Stress Echocardiography for Prediction of Long‐Term Prognosis in African Americans with Known or Suspected Coronary Artery Disease

There is limited information on noninvasive risk stratification of African Americans, a high-risk group for cardiovascular events. We investigated the value of clinical assessment and echocardiography for the prediction of a long-term prognosis in African Americans. Dobutamine echocardiography was performed in 324 African Americans. Two-dimensional measurements were performed at rest, and rest and stress wall motion was assessed. A retrospective follow-up was conducted for cardiac events: myocardial infarction (MI) or cardiac death (CD). The mean age was 59 +/- 12 years, and 83% of patients had hypertension. The follow-up was obtained in 318 (98%) patients for a mean of 5.3 years. The events occurred in 107 (33%) subjects. The independent predictors of events were history of MI (P = 0.001, risk ratio [RR] 2.04), ischemia (P = 0.007, RR 1.97), fractional shortening (P = 0.033, RR 0.08), and left atrial (LA) dimension (P = 0.034, RR 1.39). An LA size of 3.6 cm and a fractional shortening of 0.30 were the best cutoff values for the prediction of events. Prior MI, ischemia, LA size >3.6 cm, and fractional shortening <0.30 were each considered independent risk predictors for events. The event rates were 13%, 21%, 38%, 59%, and 57% in patients with 0, 1, 2, 3, and 4 risk predictors, respectively. Event-free survival progressively worsened with an increasing number of predictors: 0 or 1 versus 2 predictors, P < 0.001; 2 versus 3 or 4 predictors, P = 0.003. The long-term prognosis of African Americans can be accurately predicted by clinical assessment combined with rest and stress echocardiography.

Effect of revascularizing viable myocardium on left ventricular diastolic function in patients with ischaemic cardiomyopathy

In patients with ischaemic left ventricular (LV) dysfunction and viable myocardium, revascularization improves systolic function. Diastolic dysfunction is also present in such patients; however, whether revascularization improves diastolic function also is largely unknown. Twenty-six patients with chronic ischaemic cardiomyopathy [ejection fraction (EF) 32 +/- 6%, wall motion score index (WMSI) 2.45 +/- 0.33] and viable myocardium (low-dose dobutamine echocardiography) were examined at baseline and > or =4 months after revascularization. Diastolic function was assessed by transmitral pulsed-wave Doppler and tissue Doppler imaging (TDI) at the mitral annulus. At baseline, 62% of patients showed non-restrictive filling (non-RF) pattern, and 38% restrictive filling (RF) pattern. After revascularization, along with improvement in systolic function (EF 43 +/- 10%, WMSI 1.78 +/- 0.47, P = 0.0002 for both), diastolic filling improved in most patients, with only three patients still exhibiting RF pattern (P = 0.016); furthermore, E' velocity increased (32 +/- 42%, P = 0.0028) and E/E' decreased (-19 +/- 31%, P = 0.0378) compared with baseline. Left ventricular filling pressure also decreased, from 17.5 +/- 6.8 to 13.1 +/- 6.5 mmHg (P = 0.005). Improvement of diastolic function by TDI was related to the extent of viability at baseline (P = 0.0098) and to LV reverse remodelling after revascularization (P = 0.0092). In patients with ischaemic cardiomyopathy, LV diastolic filling may largely improve after revascularization. Improvement of diastolic dysfunction is related to the amount of viable tissue and it may represent an additional advantage of revascularizing dyssinergic but viable myocardium.

Dobutamine Stress Echocardiography Identifies Patients with Angina and Dynamic Left Ventricular Outflow Obstruction in Physiological Exercise

To determine whether patients with no heart disease who develop dynamic left ventricular outflow obstruction (DLVOTO) during dobutamine echocardiography (DE) reproduce the phenomenon during exercise echocardiography (EE), DE and EE were performed in 78 patients (59 +/- 9 years) with effort angina and no alterations in SPECT. Thirty-eight (48.7%) patients had DLVOTO during DE and 15 (19.2%) during EE. This phenomenon during EE was reproducible in 39.4% of the patients with DLVOTO on DE, and 100% of the patients with DLVOTO during EE had it during DE. Independent factors predicting DLVOTO during EE were the LVOT diameter (OR 0.33 (0.14-0.74)) and the left ventricular (LV) mass index (OR 1.05 (1.01-1.08)). No cardiovascular events were noted after 26+/-3 months. The reproducibility of DLVOTO during EE in patients with unexplained angina and with DLVOTO on DE is associated with the size of the LVOT and the LV mass index. The long-term prognosis is excellent.

Long-Term Outcome of Prophylactic Coronary Revascularization in Cardiac High-Risk Patients Undergoing Major Vascular Surgery (from the Randomized DECREASE-V Pilot Study)

Prophylactic coronary revascularization in vascular surgery patients with extensive coronary artery disease was not associated with an improved immediate postoperative outcome. However, the potential long-term benefit was unknown. This study was performed to assess the long-term benefit of prophylactic coronary revascularization in these patients. Of 1,880 patients scheduled for major vascular surgery, 430 had > or =3 risk factors (age >70 years, angina pectoris, myocardial infarction, heart failure, stroke, diabetes mellitus, and renal failure). All underwent cardiac testing using dobutamine echocardiography or nuclear stress imaging. Patients with extensive stress-induced ischemia (> or =5 segments or > or =3 walls) were randomly assigned to additional revascularization. In total, 101 patients showed extensive ischemia and were assigned to revascularization (n = 49) or no revascularization (n = 52). After 2.8 years, the overall survival rate was 64% for patients randomly assigned to no preoperative coronary revascularization versus 61% for patients assigned to preoperative coronary revascularization (hazard ratio [HR] 1.18, 95% confidence interval [CI] 0.63 to 2.19, p = 0.61). Rates for survival free of all-cause death, nonfatal myocardial infarction, and coronary revascularization were similar in both groups at 49% and 42% for patients allocated to medical treatment or coronary revascularization, respectively (HR 1.51, 95% CI 0.89 to 2.57, p = 0.13). Only 2 patients assigned to medical treatment required coronary revascularization during follow-up. Also, in patients who survived the first 30 days after surgery, there was no apparent benefit of revascularization on cardiac events (HR 1.35, 95% CI 0.72 to 2.52, p = 0.36). In conclusion, preoperative coronary revascularization in high-risk patients undergoing major vascular surgery was not associated with improved postoperative or long-term outcome compared with the best medical treatment.

Evaluation of the anti-ischemic effects of D-ribose during dobutamine stress echocardiography: a pilot study

D-Ribose, a pentose sugar, has shown to improve myocardial high-energy phosphate stores depleted by ischemia. This study investigated the ability of D-Ribose with low dose dobutamine to improve the contractile response of viable myocardium to dobutamine and to assess the efficacy of D-ribose in reducing stress-induced ischemia. Twenty-six patients with ischemic cardiomyopathy completed a two-day, randomized, double blind crossover trial comparing the effects of D-Ribose and placebo on regional wall motion. On the first study day, either D-Ribose or placebo was infused for 4.5 hours. Low (5 and 10 μ/kg/min) and subsequently, high (up to 50 μ/kg/min) dose dobutamine echocardiography was then performed. On the second study day, patients crossed over to the alternative article for a similar 4.5 hours infusion time period and underwent a similar evaluation. The wall motion response during low dose dobutamine was the same with D-Ribose and placebo in 77% of segments (203/263, Kappa = 0.37). In segments with discordant responses, more segments improved with D-Ribose than with placebo (41 vs. 19 segments, p = 0.006). With high dose dobutamine infusion, the wall motion response (ischemia vs. no ischemia) was the same with D-Ribose and placebo in 83% of interpretable segments (301/363, kappa = 0.244). In segments with discordant responses, there were more ischemic segments with placebo compared to D-Ribose (36 vs. 26, p = 0.253). Nineteen patients developed ischemia during the dobutamine and placebo infusion and 13 patients had ischemia during dobutamine and D-ribose infusion (p = 0.109). D-Ribose improved contractile responses to dobutamine in viable myocardium with resting dysfunction but had no significant effect in reducing the frequency of stress-induced wall motion abnormalities.

Automated Two-dimensional Speckle Tracking Strain Imaging for Coronary Artery Disease in Patients undergoing Dobutamine Echocardiography

Automated Two-dimensional Speckle Tracking Strain Imaging for Coronary Artery Disease in Patients undergoing Dobutamine Echocardiography

Use of a nurse-led intervention to optimize beta-blockade for reducing cardiac events after major noncardiac surgery

Although guidelines recommend the use of beta-adrenoceptor blocking drugs to reduce cardiac events (CEs) after major noncardiac surgery, trial results have varied between showing benefit, ineffectiveness, and harm. We sought whether optimizing beta-blockade (BB) delivery could make them more effective. Intermediate risk patients undergoing major noncardiac surgery (n = 400) were randomized to 2 strategies of BB therapy: universal BB (UBB; n = 197) comprising an algorithm-based, nurse-led strategy to optimize dosing and adherence to bisoprolol titration over > or =1 week preoperatively versus usual care (UC; n = 203), whereby BB are continued in those already taking them or prescribed for patients identified as high risk based on ischemia (new or inducible wall motion abnormalities) at dobutamine echocardiography (DbE). Daily electrocardiogram and troponin levels were obtained on 3 postoperative days. The primary end point was a major CE (cardiac death or myocardial infarction) within 30 days. There were 25 major CEs (6.3%), occurring in 13 (6.6%) of 197 UBB and 12 (5.9%) of 203 UC patients (OR 1.12, 95% CI 0.52-2.39). Independent predictors of CEs were baseline systolic blood pressure (beta 1.02, P = .005) and postoperative hypotension (beta 1.02, P = .03) but not treatment strategy. Those randomized to UBB had significantly better heart rate control perioperatively, at the cost of bradycardia and hypotension. The negative predictive value of DbE in this study was 95%. These data confirm a persistent CE rate after major noncardiac surgery despite nurse-led dose titration of bisoprolol. Cardiac events were equivalent to a UC strategy based on DbE results.

Incidence of Coronary Artery Disease and Necessity of Revascularization in Symptomatic Patients Requiring Permanent Pacemaker Implantation

The cause of severe cardiac conduction disturbances or sinus node dysfunction is often unknown. The objective of this study was to assess the incidence of coronary artery disease (CAD) and the necessity of revascularization in patients with symptomatic bradycardia requiring permanent pacemaker implantation and to try to find a causal association between the need for a pacemaker and the presence of CAD. From January 2002 to December 2005, 507 pacemakers were implanted due to symptomatic bradycardia. In the presence of at least one atherosclerotic risk factor, patients were recommended to undergo coronary angiography. Each patient underwent exercise or dobutamine echocardiography to detect myocardial ischemia. 212 of the 507 patients (42%) with permanent pacemaker implantation (141 men, mean age 70 +/- 9 years) underwent coronary angiography within 2 months before or after pacemaker implantation. Twelve patients (6%) had a normal angiogram. No significant CAD was found in 37 patients (17%), and significant narrowing of the coronary arteries in 150 (71%). Conservative treatment was recommended in 128 patients (60%), 40 patients (19%) were treated with percutaneous coronary intervention, and 44 patients (21%) underwent coronary artery bypass grafting. The data indicate that patients with severe conduction disturbances or sinus node dysfunction requiring permanent pacemaker implantation are more likely to have CAD with subsequent myocardial revascularization in the presence of at least one atherosclerotic risk factor. A causal association between the need for pacemaker and CAD could not be established from the results.

Abstract 2007: Effects of Myocardial Viability Assessed by Strain Stress Echocardiography on Diastolic Function in Acute Myocardial Infarction

Purpose: Myocardial viability may influence the diastolic function of left ventricle (LV) reflecting chamber remodeling in the early phase after acute myocardial infarction (AMI). However, the precise relationship in human has not been determined yet. So we aimed to evaluate whether myocardial viability assessed by strain rate parameters on low-dose dobutamine echocardiography (LD-DSE) may influence on LV diastolic function and remodeling process in AMI. Methods: In this prospective single center study, 134 consecutive patients with AMI and akinetic wall motion in at least two segments were enrolled and underwent LD-DSE on 5~9 days after the event. Myocardial viability was quantitatively evaluated by global peak systolic strain rate (psSR) and global time to peak of psSR. Within 6 hours after LD-DSE, left and right heart catheterization with the recording of LV end diastolic pressure and pulmonary capillary wedge pressure were performed. And then 6 months later, echocardiography and thallium scan with delayed image were followed. Results: Patients (67.9% men, mean age 60.1±1.1years, 54.5% anterior wall, 53.7% ST-segment elevation) were tolerated LD-DSE without significant complications. 71.6% of patients underwent revascularization therapy. After 6 months later, LV ejection fraction was significantly increased from 48.7±1.1% to 52.0±1.1% (p=0.00) and LV end diastolic volume was significantly decreased from 94.6±4.0cc to 89.1±3.8cc (p=0.00). As we expected, global psSR at baseline of LD-DSE showed significant linear correlations with LV end diastolic pressure, E/E’ ratio and left atrial volume index (r=−0.43 and p=0.01, r=0.52 and p=0.00 and r=0.52 and p=0.00, respectively). And also global psSR at 10mcg of LD-DSE correlated with E/E’ ratio and left atrial volume index(r=0.52 and p=0.00 and r=0.36 and p=0.02, respectively). Interestingly, global psSR at 10mcg of LD-DSE correlated significantly with the change of LV end diastolic volume during 6 months follow-up (r=−0.42 and p=0.04). Conclusions: Strain rate data on LD-DSE correlates with LV diastolic function in the early phase and chamber remodeling in 6 months follow-up after AMI. So strain stress echocardiography may provide useful prognostic information for LV remodeling in AMI.

Impact of coronary revascularization and transmural extent of scar on regional left ventricular remodelling

Transmural extent (TME) of myocardial scar, contractile reserve, and perfusion all predict improvement in regional myocardial function after coronary revascularization. We sought their association with regional remodelling after infarction. We studied 89 patients (age 62 +/- 10 years) with left ventricular (LV) dysfunction, at least 1 month post infarction. Viability was identified by TME < 75% on contrast-enhanced magnetic resonance imaging (ce-MRI), augmentation at low-dose dobutamine echocardiography (DbE), or >60% uptake on delayed redistribution on TI-201 SPECT (single photon emission computed tomography). Coronary revascularization was performed in 36 patients. Regional LV end-diastolic volume (EDV) and end-systolic volume, and ejection fraction were measured with MRI at baseline and after a median follow-up of 18 months. Of 357 segments identified with subendocardial infarction (TME 0-25%) on ce-MRI, 176 were revascularized. Subendocardial scar segments were associated with reverse regional remodeling during follow-up. Revascularization was an independent correlate of change in EDV, but TME and revascularization showed no interaction with respect to their influence on regional volumes. Contractile reserve was present on DbE in 228 segments, of which 129 were TME 0-25%; remodelling was associated with intervention in non-transmural infarcts showing viability by DbE. Viability was identified by TI-201 SPECT in 381 segments (233 with TME 0-25%), but viability by SPECT was not associated with reverse remodelling. No significant reverse remodelling occurred in segments with intermediate scar thickness (TME 26-75%) or transmural scar, independent of revascularization or viability by DbE or TI-SPECT. Reverse regional remodelling is associated with subendocardial infarction, especially in the setting of contractile reserve and revascularization.

Left Ventricular Remodeling can be Predicted with Left Ventricular Volume Response During Dobutamine Echocardiography After Acute Myocardial Infarction

This study was performed to evaluate the significance of left ventricular (LV) volume response during dobutamine stress echocardiography (DSE) in the prediction of LV volume change during follow-up (F/U) in patients with acute myocardial infarction (AMI). Forty-five patients with AMI (male 39, age 57+/-10 y, anterior myocardial infarction [MI] 29) underwent DSE 6+/-4 d after AMI. Revascularization of the infarct-related artery was performed if severe stenosis was present. A F/U echocardiography was performed 7.5+/-3.4 mo after DSE. The LV end-diastolic volume (EDV) and end-systolic volume (ESV) using the modified Simpson's method were measured at baseline echocardiography, low-dose (10 microg x kg(-1) x min(-1)) DSE, and F/U echocardiography. Patients were divided into 2 groups; Group I (n = 21) with an abnormal response (<10% decrease) in LVEDV during low-dose DSE; Group II (n = 24) with a normal response (> or =10% decrease) in LVEDV during low-dose DSE. At F/U echocardiography, the (%) change of LVEDV was significantly different between the 2 groups (-2.0+/-16.7 versus - 22.6+/-24.7%, p<0.01). Using multivariate analysis, the response of LVEDV (%) at low-dose DSE was the only significant independent predictor of the change of LVEDV (%) during F/U (y = 0.85 x - 0.03, r = 0.63, p<0.001). The response of LVEDV during DSE can be used as a predictor for the LV volume change after AMI.

Left ventricular apical ballooning syndrome: Prevalence, clinical characteristics and pathogenetic mechanisms in a European population

Background Left ventricular apical ballooning syndrome (LVABS) is a cardiac syndrome mimicking acute myocardial infarction, whose prevalence in western populations and pathogenesis are not yet well defined. The aim of the study was to assess its prevalence, clinical characteristics and pathophysiological mechanisms in a European population of myocardial infarction patients. Methods Of a series of 1457 patients with acute myocardial infarction 18 fulfilled the diagnostic criteria for LVABS. To evaluate the pathogenetic mechanisms we studied coronary blood flow with TIMI flow grade and corrected TIMI frame count (CTFC) in all patients and performed provocative testing with ergonovine and dobutamine echocardiography in 14. Results All patients were women aged 72 ± 9 years. A triggering event was identifiable in 39% of cases. LV ejection fraction in the acute phase was 46 ± 5%. No deaths or major complications occurred during hospitalization. Response to ergonovine was negative in all 14 patients and dobutamine induced a dynamic LV obstruction in 4/14 (28%). Mean CTFC was abnormally prolonged in all 3 major coronary arteries and 16/18 patients (89%) had an abnormal CTFC in ≥ 1 coronary vessel. No cardiac deaths occurred during follow-up and 1 patient only had a recurrence. Conclusions The prevalence of LVABS is 1.2% among all patients with acute myocardial infarction, but rises to 4.9% in women. Short- and long-term prognosis is good. Abnormal CTFC suggests the presence of a coronary microvascular dysfunction, while dynamic LV obstruction can contribute to the development of LVABS in a minority of patients.

Prognostic implications of negative dobutamine stress echocardiography in African Americans compared to Caucasians

BackgroundAfrican Americans (AA) have higher rates of cardiovascular morbidity and mortality than Caucasians (CA). Despite its excellent negative predictive value, the influence of race on the prognostic implications of negative dobutamine echocardiography in predicting major cardiac problems is largely unknown.MethodsWe studied 387 AA and 340 CA patients with negative dobutamine stress echocardiography (NDSE). Kaplan-Meier survival analysis was used to create freedom-from-event curves for major adverse cardiac events over a 36-month period, and a Cox proportional-hazards multivariable model to examine the influence of race on cardiac outcomes.ResultsAA patients were younger (69.4 ± 12.6 vs. 74.2 ± 10.7, p < .001), had higher incidence of diabetes mellitus (37% vs. 29%, p = .01), hypertension (91% vs. 85%, p = .006), left ventricular hypertrophy (70% vs. 49%, p < .001) and lower incidence of prior coronary artery disease (27% vs. 34%, p = .05) compared to CA patients. Ejection fraction ≥ 50% was comparable (81% vs. 82%, p = .8). At 3-years, AA patients had a lower freedom from nonfatal myocardial infarction (92% vs. 96%, p = .006) and any cardiac event (cardiac death, myocardial infarction) (91% vs. 95%, p = .005) compared to CA patients.ConclusionThis is the first study to demonstrate that AA patients have higher rates of nonfatal MI and MACE compared to CA patients with a NDSE. These patients require closer follow-up and aggressive preventive and treatment strategies should be employed to help reduce cardiovascular morbidity and mortality despite negative ischemic workup.

Normalization of Ejection Fraction and Resolution of Symptoms in Chronic Severe Heart Failure is Possible With Modern Medical Therapy: Clinical Observations in 11 Patients

This report describes the normalization of left ventricular ejection fraction and resolution of signs and symptoms of chronic and severe heart failure in both male and female patients (mean age 54 years) treated with standard medical therapy. These observations were made in 11 patients with idiopathic dilated cardiomyopathy treated in a single cardiology practice, who had evidence of myocardial "viability" (dysfunctional but noncontractile myocardium that has the potential for improvement in function) as assessed by cardiac magnetic resonance imaging, low-dose dobutamine echocardiography, or nuclear imaging. These patients were treated with standard available therapies including beta-blockers, angiotensin-converting enzyme inhibitors, digoxin, and potassium and non-potassium-sparing diuretics. The average ejection fraction at presentation was 17% +/- 9% which improved to 59% +/- 5%. All patients improved to New York Heart Association functional class I with available therapy. The majority of patients received micronutrient supplementation with coenzyme Q10, vitamin B1, and amino acids, which target the pathways of cardiac metabolism and may aid in the restoration of cardiac function. This case series demonstrates that normalization of cardiac function is possible with standard therapy and the importance of assessing myocardial viability in all patients with heart failure and reduced ejection fraction. Given the unique metabolic needs of the failing heart, the role of micronutrients in combination with standard therapy warrants further investigation.

Strain Rate Analysis and Levosimendan Improve Detection of Myocardial Viability by Dobutamine Echocardiography in Patients With Post-Infarction Left Ventricular Dysfunction: A Pilot Study

The assessment of myocardial viability by wall motion (WM) analysis on dobutamine echocardiography is subjective and provides suboptimal results. The aim of this study was to test the hypothesis that the prediction of functional recovery after revascularization can be improved by combining strain rate (SR) imaging, an objective method to quantify regional function, and levosimendan, a positive inotropic and vasodilator agent with no adrenergic effects. Thirty postinfarction patients (mean age, 65 +/- 13 years) underwent, off drug, dobutamine (5-40 mug/kg/min) and then levosimendan (24 mug/kg in 10 minutes) echocardiography before percutaneous coronary intervention. WM score, peak systolic SR (SRs), end-systolic strain (Ses), and postsystolic strain (Sps) were assessed in all segments. Regional left ventricular functional recovery was identified by >/=1-point improvement in WM as assessed using the standard 16-segment model. Of 215 segments with abnormal resting function, 102 (47%) showed improvement in WM 8 months after revascularization. Functional recovery was predicted in 60 segments with dobutamine and in 76 segments with levosimendan (sensitivity, 59% vs 75%; P = .026), while failure to recover was identified in 93 segments with dobutamine and 90 segments with levosimendan (specificity, 82% vs 80%, P = NS). Overall there was significant agreement between the 2 tests (kappa = 0.73; P < .0001). Peak SRs in segments with functional recovery improved significantly (P = .001) with both dobutamine and levosimendan (from -1.36 +/- 0.41 to -1.87 +/- 0.59 and -1.99 +/- 0.49, respectively) but did not change in regions with unchanged WM at follow-up. There were no significant differences in Ses and Sps between rest and pharmacologic tests, with either dobutamine or levosimendan. Of note, an increment in peak SRs > -0.29 s(-1) after levosimendan had the highest specificity (93%) for predicting segmental functional recovery at follow-up (P = .001). The combination of a newer quantitative echocardiographic technique (SR analysis) and a newer pharmacologic agent (levosimendan) improves the sensitivity of viability assessment compared with conventional dobutamine echocardiography.

Myocardial blood flow in patients with low-flow, low-gradient aortic stenosis: differences between true and pseudo-severe aortic stenosis. Results from the multicentre TOPAS (Truly or Pseudo-Severe Aortic Stenosis) study

Background:Impairment of myocardial flow reserve (MFR) in aortic stenosis (AS) with normal left ventricular function relates to the haemodynamic severity.Objectives:To investigate whether myocardial blood flow (MBF) and MFR differ in...

A Randomized Cross-Over Study for Evaluation of the Effect of Image Optimization With Contrast on the Diagnostic Accuracy of Dobutamine Echocardiography in Coronary Artery Disease: The OPTIMIZE Trial

The purpose of this study was to evaluate whether the addition of a contrast agent to dobutamine stress echocardiography (DSE) improves its diagnostic accuracy for coronary artery disease (CAD) and to determine the effect of image quality on the diagnostic impact of contrast agent use in this setting. Contrast agents can improve endocardial border definition. To date, however, there are no randomized trials that have evaluated the impact of contrast agent use on the accuracy of DSE. Patients referred for stress testing with dobutamine echocardiography underwent 2 DSE studies: 1 with and 1 without a contrast agent, at least 4 h apart in a randomized order and within a 24-h period. A total of 101 patients underwent both DSE studies. Similar hemodynamics were achieved during the 2 stress testing sessions. The use of a contrast agent improved the percentage of segments adequately visualized at baseline (from 72 +/- 24% to 95 +/- 8%) and more so at peak stress (67 +/- 28% to 96 +/- 7%); both p < 0.001. Interpretation of wall motion with high confidence also increased with contrast agent use from 36% to 74% (p < 0.001). Segment visualization with the use of a contrast agent improved in all views, but was more pronounced in the apical views. In unenhanced DSE, 36% of studies were normal, 51% had ischemia, and 8% were uninterpretable-all of which became interpretable with the use of a contrast agent. When compared with angiography (n = 92; 55 patients with CAD), accurate detection of ischemia was higher with contrast-enhanced studies versus nonenhanced studies (p = 0.02). As endocardial visualization and confidence of interpretation decreased in unenhanced studies, a greater impact of the use of a contrast agent on DSE accuracy was observed (p < 0.01). During dobutamine stress echocardiography, contrast agent administration improves endocardial visualization at rest and more so during stress, leading to a higher confidence of interpretation and greater accuracy in evaluating CAD. The lesser the endocardial border visualization, the higher the impact of contrast echocardiography on accuracy.

Identification and viability assessment of infarcted myocardium with late enhancement multidetector computed tomography: Comparison with thallium single photon emission computed tomography and echocardiography

Recent studies revealed that multidetector computed tomography late enhancement (MDCT-LE) is a reliable technique for detecting necrotic and scarred myocardial tissue. The aims of the study were to identify infarcted myocardium using MDCT-LE protocol in patients after myocardial infarction (MI) and assess viability in resting wall motion abnormalities. One hundred one patients with previous MI (62 +/- 13 years, 1-6 months after MI) underwent MDCT-LE (15 minutes after contrast medium administration), rest-redistribution thallium single photon emission computed tomography (Tl-SPECT), and dobutamine echocardiography (DbE). In a 17-segment model, infarcted myocardium detected by MDCT-LE was categorized as none, 1%-25%, 26%-50%, 51%-75%, or >75% segmental extent and was compared with decreased uptake of Tl-SPECT and contractile function by DbE on per patient and segmental basis in a blinded fashion. By per patient analysis, MDCT-LE identified the presence of infarcted myocardium in 97 patients (96%), and Tl-SPECT decreased uptake in 88 patients (87%), (P = .02). By per segment analysis, the concordance for detecting infarcted myocardium was good (kappa value = 0.792). In segments with resting wall motion abnormalities (N = 486), there was moderate concordance in assessing viability (kappa value between MDCT and Tl-SPECT = 0.555, MDCT and DbE = 0.498, Tl-SPECT and DbE = 0.478) with predefined MDCT-LE threshold of 50% segmental extent. Among segments with MDCT-LE >75% segmental extent, the proportion designated nonviable by Tl-SPECT and DbE reached 87.8% and 92.2%, respectively. Multidetector computed tomography late enhancement is accurate in identifying the presence and extent of infarcted myocardium. Its segmental extent has good correlation with the magnitude of thallium decreased uptake and can predict contractile reserve. Multidetector computed tomography late enhancement can be an alternative to assess viability.

Stunning, Hibernation, and Assessment of Myocardial Viability

The last 3 decades have witnessed an unprecedented improvement in the outcome of patients with acute coronary syndromes. The widespread use of thrombolytic therapy and percutaneous coronary interventions, in association with increasingly potent antithrombotic agents, has contributed to significant reductions in mortality and morbidity in these patients. Although overall survival has improved, a downside of this success has been the greater number of patients with residual left ventricular (LV) dysfunction undergoing progressive LV remodeling and congestive heart failure. This problem is compounded by the rising age of our population and the higher prevalence of comorbidities such as diabetes mellitus that confer an increased risk of coronary artery disease (CAD) and congestive heart failure. Patients with CAD represent by far the most numerous cohort among those with congestive heart failure, and their treatment remains a partial success.1 Typically, these patients have multivessel disease, increased LV volumes, and variable degrees of regional and/or global systolic dysfunction, although more cases of isolated diastolic dysfunction have been reported recently.2–4 In these patients, coronary revascularization may lead to symptomatic and prognostic improvement, and these clinical benefits are accompanied by evidence of reverse LV remodeling. In this context, the concept of myocardial viability was developed and a number of different techniques have been used to demonstrate the presence of viable tissue before coronary revascularization. The aim of this review article is to summarize our current understanding of the concept of myocardial viability and its clinical implications in patients with CAD and chronic LV dysfunction. Throughout this review, we use the term viability to describe dysfunctional myocardium subtended by diseased coronary arteries with limited or absent scarring that therefore has the potential for functional recovery. Viability is a prospective definition, but it does not imply evidence of functional recovery after interventions. The term hibernation, which …