It has recently been demonstrated that high-energy diagnostic transthoracic ultrasound and intravenous microbubbles dissolve thrombi (sonothrombolysis) and increase angiographic recanalization rates ...in patients with ST-segment-elevation myocardial infarction. We aimed to study the effect of sonothrombolysis on the myocardial dynamics and infarct size obtained by real-time myocardial perfusion echocardiography and their value in preventing left ventricular remodeling.
One hundred patients with ST-segment-elevation myocardial infarction were randomized to therapy (50 patients treated with sonothrombolysis and percutaneous coronary intervention) or control (50 patients treated with percutaneous coronary intervention only). Left ventricular volumes, ejection fraction, risk area (before treatment), myocardial perfusion defect over time (infarct size), and global longitudinal strain were determined by quantitative real-time myocardial perfusion echocardiography and speckle tracking echocardiography imaging.
Risk area was similar in the control and therapy groups (19.2±10.1% versus 20.7±8.9%;
=0.56) before treatment. The therapy group presented a behavior significantly different than control group over time (
<0.001). The perfusion defect was smaller in the therapy at 48 to 72 hours even in the subgroup of patients with no recanalization at first angiography (12.9±6.5% therapy versus 18.8±9.9% control;
=0.015). The left ventricular global longitudinal strain was higher in the therapy than control immediately after percutaneous coronary intervention (14.1±4.1% versus 12.0±3.3%;
=0.012), and this difference was maintained until 6 months (17.1±3.5% versus 13.6±3.6%;
<0.001). The only predictor of left ventricular remodeling was treatment with sonothrombolysis: the control group was more likely to exhibit left ventricular remodeling with an odds ratio of 2.79 (95% CI, 0.13-6.86;
=0.026).
Sonothrombolysis reduces microvascular obstruction and improves myocardial dynamics in patients with ST-segment-elevation myocardial infarction and is an independent predictor of left ventricular remodeling over time.
Background: Real time myocardial contrast echocardiography (RTMCE) is an emerging imaging modality for assessing myocardial perfusion that allows for noninvasive quantification of regional myocardial ...blood flow (MBF). Aim: We sought to assess the value of qualitative analysis of myocardial perfusion and quantitative assessment of myocardial blood flow (MBF) by RTMCE for predicting regional function recovery in patients with ischemic heart disease who underwent coronary artery bypass grafting (CABG). Methods: Twenty‐four patients with coronary disease and left ventricular systolic dysfunction (ejection fraction <45%) underwent RTMCE before and 3 months after CABG. RTMCE was performed using continuous intravenous infusion of commercially available contrast agent with low mechanical index power modulation imaging. Viability was defined by qualitative assessment of myocardial perfusion as homogenous opacification at rest in ≥2 segments of anterior or ≥1 segment of posterior territory. Viability by quantitative assessment of MBF was determined by receiver‐operating characteristics curve analysis. Results: Regional function recovery was observed in 74% of territories considered viable by qualitative analysis of myocardial perfusion and 40% of nonviable (P = 0.03). Sensitivity, specificity, positive and negative predictive values of qualitative RTMCE for detecting regional function recovery were 74%, 60%, 77%, and 56%, respectively. Cutoff value of MBF for predicting regional function recovery was 1.76 (AUC = 0.77; 95% CI = 0.62–0.92). MBF obtained by RTMCE had sensitivity of 91%, specificity of 50%, positive predictive value of 75%, and negative predictive value of 78%. Conclusion: Qualitative and quantitative RTMCE provide good accuracy for predicting regional function recovery after CABG. Determination of MBF increases the sensitivity for detecting hibernating myocardium. (Echocardiography 2011;28:342‐349)
To test the effects of exercise training on sleep and neurovascular control in patients with systolic heart failure with and without sleep disordered breathing.
Prospective interventional study.
...Cardiac rehabilitation and exercise physiology unit and sleep laboratory.
Twenty-five patients with heart failure, aged 42 to 70 years, and New York Heart Association Functional Class I-III were divided into 1 of 3 groups: obstructive sleep apnea (n=8), central sleep apnea (n=9) and no sleep apnea (n=7). INTERVENTIONS Four months of no-training (control) followed by 4 months of an exercise training program (three 60-minute, supervised, exercise sessions per week).
Sleep (polysomnography), microneurography, forearm blood flow (plethysmography), peak VO2, and quality of life were evaluated at baseline and at the end of the control and trained periods. No significant changes occurred in the control period. Exercise training reduced muscle sympathetic nerve activity (P < 0.001) and increased forearm blood flow (P < 0.01), peak VO2( P < 0.01), and quality of life (P < 0.01) in all groups, independent of the presence of sleep apnea. Exercise training improved the apnea-hypopnea index, minimum 0O saturation, and amount stage 3-4 sleep (P < 0.05) in patients with obstructive sleep apnea but had no significant effects in patients with central sleep apnea.
The beneficial effects of exercise training on neurovascular function, functional capacity, and quality of life in patients with systolic dysfunction and heart failure occurs independently of sleep disordered breathing. Exercise training lessens the severity of obstructive sleep apnea but does not affect central sleep apnea in patients with heart failure and sleep disordered breathing.
Natural myocardial markers, or speckles, originated from constructive and destructive interference of ultrasound in the tissues may provide early diagnosis of myocardial changes and be used in the ...prediction of some cardiac events. Due to its relatively temporal stability, speckles can be tracked by dedicated software along the cardiac cycle, enabling the analysis of the systolic and diastolic function. They are identified by either conventional 2D grey scale and by 3D echo, conferring independence of the insonation angle, thus allowing assessment of cardiac mechanics in the three spatial planes: longitudinal, circumferential, and radial. The purposes of the present paper are: to discuss the role and the meaning of cardiac strain obtained by speckle tracking during the evaluation of cardiac physiology and to discuss clinical applications of this novel echocardiographic technology.
Although dobutamine–atropine stress echocardiography (DASE) is an established method for evaluating patients who have coronary artery disease (CAD), it can increase test duration and a patient's ...exposure to large doses of dobutamine. New protocols, including the early injection of atropine during dobutamine stress echocardiography (EA-DSE), have been proposed to decrease test duration. This study compared the safety, efficacy, and accuracy of EA-DSE with those of DASE. We retrospectively evaluated 3,163 patients who underwent DASE and 1,664 patients who underwent EA-DSE over a period of 12 years. In EA-DSE, atropine at a dose ≤2 mg was started with 20 μg/kg/min of dobutamine if heart rate was <100 beats/min. Diagnostic accuracy for detecting CAD (>50% stenosis) was assessed in patients who underwent quantitative angiography ≤3 months of stress testing. The dobutamine dose used in EA-DSE was smaller than that used in DASE (31 ± 6 vs 36 ± 6 μg/kg/min, p <0.0001), although the atropine dose was larger (0.8 ± 0.5 vs 0.5 ± 0.25 mg, p <0.0001). EA-DSE resulted in a significantly shorter duration of dobutamine infusion (12.4 ± 2.0 vs 14.6 ± 2.5 minutes, p <0.0001), more diagnostic studies (88% vs 81%, p <0.0001), and a lower incidence of minor adverse effects than did DASE. The rate of major adverse effects was similar in the 2 protocols. Sensitivities, specificities, positive predictive values, negative predictive values, and accuracies for detecting CAD were 84%, 90%, 93%, 76%, and 86% for EA-DSE and 86%, 78%, 84%, 79%, and 82% for DASE, respectively (p = NS). Therefore, EA-DSE is a safe and effective alternative to DASE and had a similar accuracy for the detection of CAD.
Background Few data exist on the degree of interstitial myocardial fibrosis in patients with classical low-flow, low-gradient aortic stenosis (LFLG-AS) and its association with left ventricular flow ...reserve (FR) on dobutamine stress echocardiography. This study sought to evaluate the diffuse interstitial fibrosis measured by T1 mapping cardiac magnetic resonance technique in LFLG-AS patients with and without FR. Methods Prospective study including 65 consecutive patients (41 LFLG-AS mean age, 67.1±8.4 years; 83% men and 24 high-gradient aortic stenosis used as controls) undergoing dobutamine stress echocardiography to assess FR and cardiac magnetic resonance to determine the extracellular volume (ECV) fraction of the myocardium, indexed ECV (iECV) to body surface area and late gadolinium enhancement. Results Interstitial myocardial fibrosis measured by iECV was higher in patients with LFLG-AS with and without FR as compared with high-gradient aortic stenosis (35.25±9.75 versus 32.93±11.00 versus 21.19±6.47 mL/m
, respectively; P<0.001). However, both ECV and iECV levels were similar between LFLG-AS patients with and without FR ( P=0.950 and P=0.701, respectively). Also, FR did not correlate significantly with ECV (r=-0.16, P=0.31) or iECV (r=0.11, P=0.51). Late gadolinium enhancement mass was also similar in patients with versus without FR but lower in high-gradient aortic stenosis (13.3±10.2 versus 10.5±7.5 versus 4.8±5.9 g, respectively; P=0.018). Conclusions Patients with LFLG-AS have higher ECV, iECV, and late gadolinium enhancement mass compared with high-gradient aortic stenosis. Moreover, among patients with LFLG-AS, the degree of myocardial fibrosis was similar in patients with versus those without FR. These findings suggest that diffuse myocardial fibrosis may not be the main factor responsible for the absence of FR in LFLG-AS patients.
Background: Although dobutamine‐atropine stress echocardiography (DASE) has been widely used for evaluating patients with coronary artery disease (CAD), dynamic changes that occur at microcirculatory ...level during each stage of stress have not been demonstrated in humans. Aim: We sought to determine variations in myocardial blood flow (MBF) during DASE using quantitative real time myocardial contrast echocardiography (RTMCE). Methods: We studied 45 patients who underwent coronary angiography and RTMCE. Replenishment velocity of microbubbles in the myocardium (β) and MBF reserves were obtained at baseline, intermediate stage (70% of maximal predicted heart rate), peak stress, and recovery phase. Results: β and MBF reserves were lower in patients with than without CAD at intermediate (1.65 vs. 2.10; P = 0.001 and 2.44 vs. 3.23; P = 0.004) and peak (1.63 vs. 3.00; P < 0.001 and 2.14 vs. 3.98; P < 0.001, respectively). In patients without CAD, β, and MBF reserves increased from intermediate to peak and decreased at recovery, while in those without CAD reserves did not change significantly. Optimal cutoff values of β reserve at intermediate, peak, and recovery were 1.78, 2.09, and 1.70, with areas under the curves of 0.80 (95%CI = 0.67–0.94), 0.89 (95%CI = 0.79–0.99), and 0.69 (95%CI = 0.53–0.85). Sensitivity, specificity and accuracy for detecting CAD at intermediate stage were 68% (95%CI = 48–89), 85% (95%CI = 71–98), and 78% (95%CI = 66–90), at peak stress were 79% (95%CI = 61–97), 96% (95%CI = 89–100), and 89% (95%CI = 80–98), and at recovery were 74% (95%CI = 54–93), 65% (95%CI = 47–84), and 69% (95%CI = 55–82), respectively. Conclusion: RTMCE allows for quantification of dynamic changes in microcirculatory blood flow at each stage of DASE. The best parameter for detecting CAD in all stages was β reserve. (Echocardiography 2011;28:993‐1001)
We studied the value of a rapid beta-blocker injection at peak dobutamine-atropine stress echocardiography (DASE) for the detection of coronary artery disease (CAD).
The presence of tachycardia and ...hyperdynamic wall motion may make it difficult to recognize a new wall motion abnormality (NWMA) at peak stress.
We studied 101 patients (mean age 58.2 +/- 9.8 years) who underwent effective DASE and coronary angiography. All patients received a rapid intravenous injection of metoprolol immediately after peak DASE image acquisition. Positivity in combined peak plus post-metoprolol images was defined when there was only peak NWMA, maintenance of peak NWMA, or NWMA detected only after metoprolol injection. Significant CAD was defined as >or=50% stenosis by quantitative angiography.
There were 37 patients without and 64 with CAD. The sensitivity, specificity, accuracy, and positive and negative predictive values for the detection of CAD at peak stress were 84%, 92%, 87%, 95%, and 77%, respectively. Five patients with CAD had negative peak images that became positive only after metoprolol. Extension of peak NWMA during metoprolol was observed in 14 patients, and multivessel CAD was detected in 10 of them. The sensitivity, specificity, accuracy, and positive and negative predictive values for peak plus metoprolol images were 92%, 89%, 91%, 94%, and 87%, respectively.
The use of metoprolol injected at peak of dobutamine infusion improved the detection of CAD by DASE.
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