Intravenous Myocardial Contrast Echocardiography Research Articles

Myocardial blood volume reserve by intravenous contrast echocardiography predicts improvement in left ventricular function in patients with nonischemic dilated cardiomyopathy.

Impaired myocardial perfusion has been shown in nonischemic dilated cardiomyopathy (DCM). Intravenous myocardial contrast echocardiography (MCE) has been introduced to examine myocardial blood volume (MBV) noninvasively. This study was designed to evaluate if MBV reserve assessed by intravenous MCE with adenosine triphosphate (ATP) can predict efficacy of optimal medical therapy in patients with DCM. Fifteen DCM patients and 8 control subjects underwent conventional echocardiography and intravenous MCE. We obtained the change in peak contrast integrated backscatter intensity (∆PI) by ATP on the left ventricular (LV) anteroseptal myocardium. After 3months of optimal medical therapy in DCM patients, we reperformed conventional echocardiography. A good responder to therapy was defined as a decrease in LVDd>5mm to final LVDd<55mm and increase in LVEF>20% to final LVEF>45%. In DCM patients, ∆PI was lower compared to controls (p<0.001). Good responders to therapy (n=6) had higher ∆PI than poor responders (n=9) (p<0.05). The present study demonstrates that the response to the medical therapy in DCM is predicted by the assessment of dilator reserve in MBV. Intravenous MCE with ATP may provide useful information to evaluate MBV reserve.

Establishment and characterization of a minipig model of microvascular coronary artery spasm

To observe the feasibility of establishing a porcine model of microvascular coronary artery spasm by intracoronary neuropeptide Y (NPY) infusion, and to analyze the characterization of this model. Minipigs were divided into four groups (n = 4 each): normal saline (NS) group, 1 nmol NPY group, 3 nmol NPY group, and 6 nmol NPY group. Arterial sheaths were planted into bilateral femoral arteries of minipigs. A pigtail catheter was placed at the left sheath to determine the hemodynamic parameters. NS and different doses of NPY were injected into the left anterior descending branch through the right sheath. Intravenous myocardial contrast echocardiography (MCE) was applied to measure the microvessel volume (α), filling velocity (β), and microcirculation blood flow (MBF) before and at 10 and 30 minutes after NS and NPY injection. Before and after injection, there were no difference in α, β and MBF between NS and 1 nmol NPY group (all P > 0.05). In 3 nmol NPY group, α and MBF decreased at 10 min (P < 0.01 and 0.05, respectively), which were recovered at 30 min except α. Reductions of β (P < 0.05) and MBF (P < 0.01) were observed at 10 min in 6 nmol NPY group, which were recovered at 30 min, but MBF still remained lower than at baseline (P < 0.01) and compared to 3 nmol NPY group (P < 0.05). Intracoronary injection of NPY into the anterior descending coronary artery can establish the porcine model of microvascular coronary artery spasm, which might serve as a useful animal model for coronary microvascular studies.

Intravenous myocardial contrast echocardiography can predict recurrence of pressure gradient of left ventricular outflow tract in hypertrophic obstructive cardiomyopathy after percutaneous transluminal septal myocardial ablation

Percutaneous transluminal septal myocardial ablation (PTSMA) is appropriate in patients who are refractory to medical treatments for hypertrophic obstructive cardiomyopathy (HOCM). However, about 10% of patients show recurrence of left ventricular outflow tract pressure gradient (LVOG) after PTSMA and need repeat PTSMA. The authors describe two HOCM cases who underwent intravenous myocardial contrast echocardiography (IVMCE) at two weeks after PTSMA. IVMCE revealed the total defect of the PTSMA area in one patient, a 69-year-old woman. This patient has shown no recurrence of LVOG for 4 years. Faintly stained PTSMA area by IVMCE was seen in the other patient, an 83-year-old woman. This patient had a recurrence of LVOG 3 months later. Therefore, in conclusion, IVMCE might predict recurrence of LVOG after PTSMA.

Exogenous adenosine triphosphate disodium administration during primary percutaneous coronary intervention reduces no-reflow and preserves left ventricular function in patients with acute anterior myocardial infarction: A study using myocardial contrast echocardiography

Background It is unknown whether adenosine triphosphate disodium (ATP) administration during primary percutaneous coronary intervention (PCI) is useful in anterior acute myocardial infarction (AMI). Methods The study was a prospective, non-randomized, open-label trial. Primary PCI was successfully performed in 204 consecutive patients with first anterior AMI. ATP at a mean dose of 117 μg/kg/min for 45 min on an average was infused intravenously during PCI in 100 patients (Group 1). In the other 104 patients, normal saline was administered (Group 2). ST-segment resolution (STR) was estimated 90 min after recanalization. The no-reflow ratio was measured 2 weeks later, using intravenous myocardial contrast echocardiography. Left ventricular ejection fraction (LVEF), LV regional wall motion (LVRWM), and LV end-diastolic volume index (LVEDVI) were measured 6 months later. Results Baseline patient characteristics of the two groups were similar, including TIMI risk scores. Significant STR (≧ 50% resolution compared to baseline) (66% versus 50%; Group 1 versus Group 2, p = 0.02), no-reflow ratio (24% versus 34%, indicated by mean values, p = 0.02), LVEF (61% versus 55%, p = 0.0007), LVRWM (− 1.56 versus − 2.05, using the SD/chord, p = 0.0001), and LVEDVI (60 ml/m 2 versus 71 ml/m 2, p = 0.0007) were significantly better in Group 1, and the no-reflow ratio, LVEF, LVRWM and LVEDVI were significantly better in ATP-administered patients, regardless of antecedent angina or advanced age. ATP Administration was consistently identified as a significant determinant for STR, no-reflow ratio, LVEF, LVRWM, and LVEDVI. Conclusions Intravenous ATP administration during reperfusion is an independent determinant of STR and the no-reflow ratio, and LVEF, LVRWM, and LVEDVI at 6 months after primary PCI.

Abstract 4710: Diagnostic Accuracy of Myocardial Perfusion on Myocardial Contrast Echocardiography in Patients with Acute Coronary Syndrome: Results from the Assessment of Coronary Heart Disease with Myocardial Contrast Echocardiography 2 (ACTMCE2) Multicenter Trial

Background: Intravenous myocardial contrast echocardiography (MCE) at rest and during vasodilator stress is a reliable bedside technique for assessment of myocardial perfusion in patients with coronary artery disease. The aim of this study is to evaluate diagnostic accuracy of myocardial perfusion abnormalities using MCE at rest in patients with acute coronary syndrome (ACS). This study is the first MCE multicenter trial for the evaluation of ACS in Japan. Methods: We performed triggered MCE at rest in 102 patients (mean age: 65 ± 11 years) with suspected ACS. We obtained 1:1 and 1:6 end-systolic triggered MCE images at four- and two-chamber views. We detected myocardial ischemia by the appearance of myocardial perfusion abnormalities (defect or reduction) in 1:1 end-systolic triggered MCE image. We assessed the appearance of regional wall motion abnormality (RWMA) at the same time. Quantitative coronary angiography was performed in all patients within 1 week (2.6 ± 2.2 days) after MCE. Results: Eighty-four of 102 (82%) patients were diagnosed ACS (unstable angina: 70 patients; non-ST-segment elevation myocardial infarction: 11 patients; ST-segment elevation myocardial infarction: 3 patients) and demonstrated significant coronary artery stenosis (stenosis = or &gt;75%) that required coronary revascularization therapy. The sensitivity, specificity, and accuracy of myocardial perfusion abnormality by MCE at rest for diagnosing ACS were 79%, 86%, and 83%, respectively. On each coronary artery, the sensitivity, specificity, and accuracy of MCE for diagnosing ACS were 85%, 71%, and 79% in the left anterior descending artery; 70%, 92%, and 84% in the left circumflex artery; 77%, 89%, and 84% in the right coronary artery, respectively. The sensitivity, specificity, and accuracy of RWMA for diagnosing ACS were 49%, 90%, and 71%, respectively, and the sensitivity of MCE for diagnosing ACS was significantly higher than that of RWMA. Conclusion: Intravenous myocardial contrast echocardiography at rest without stress examination is a feasible noninvasive method for accurate diagnosis of ACS. In this multicenter study, MCE at rest improved the diagnostic accuracy of echocardiography for diagnosing ACS.

Evaluation of myocardial viability after myocardial infarction with intravenous real-time myocardial contrast echocardiography

The myocardial viability after myocardial infarction was evaluated by intravenous myocardial contrast echocardiography. Intravenous real-time myocardial contrast echocardiography was performed on 18 patients with myocardial infarction before coronary revascularization. Follow-up echocardiography was performed 3 months after coronary revascularization. Segmental wall motion was assessed using 18-segment LV model and classified as normal, hypokinesis, akinesis and dyskinesis. Viable myocardium was defined by evident improvement of segmental wall motion 3 months after coronary revascularization. Myocardial perfusion was assessed by visual interpretation and divided into 3 conditions: homogeneous opacification; partial or reduced opacification or subendocardial contrast defect; contrast defect. The former two conditions were used as the standard to define the viable myocardium. The results showed that 109 abnormal wall motion segments were detected among 18 patients with myocardial infarction, including 47 segments of hypokinesis, 56 segments of akinesis and 6 segments of dyskinesis. The wall motion of 2 segments with hypokinesis before coronary revascularization which showed homogeneous opacification, 14 of 24 segments with hypokinese and 20 of 24 segments with akinese before coronary revascularization which showed partial or reduced opacification or subendocardial contrast defect was improved 3 months after coronary revascularization. In our study, the sensitivity and specificity of evaluation of myocardial viability after myocardial infarction by intravenous real-time myocardial contrast echocardiography were 94.7% and 78.9%, respectively. It was concluded that intravenous real-time myocardial contrast echocardiography could accurately evaluate myocardial viability after myocardial infarction.

Evaluation of the left ventricular remodeling in patients with myocardial infarction after revascularization with intravenous real-time myocardial contrast echocardiography

In order to evaluate the left ventricular remodeling in patients with myocardial infarction after revascularization with intravenous real-time myocardial contrast echocardiography (RT-MCE), intravenous RT-MCE was performed on 20 patients with myocardial infarction before coronary revascularization. Follow-up echocardiography was performed 3 months after coronary revascularization. Segmental wall motion was assessed using 18-segment LV model and classified as normal, hypokinesis, akinesis and dyskinesis. Myocardial perfusion was assessed by visual interpretation and divided into 3 conditions: homogeneous opacification=1; partial or reduced opacification or subendocardial contrast defect=2; contrast defect=3. Myocardial perfusion score index (MPSI) was calculated by dividing the total sum of contrast score by the total number of segments with abnormal wall motion. Twenty patients were classified into 2 groups according to the MPSI: MPSI<or=1.5 as good myocardial perfusion, MPSI>1.5 as poor myocardial perfusion. To assess the left ventricular remodeling, the following comparisons were carried out: (1) Comparisons of left ventricular ejection fraction (LVEF), left ventricular end-systolic volume (LVESV) and left ventricular end-diastolic volume (LVEDV) before and 3 months after revascularization in two groups; (2) Comparisons of LVEF, LVESV and LVEDV pre-revascularization between two groups and comparisons of these 3 months post-revascularization between two groups; (3) Comparisons of the differences in LVEF, LVESV and LVEDV between 3 months post-and pre-revascularization (DeltaLVEF, DeltaLVESV and DeltaLVEDV) between two groups; (4) The linear regression analysis between DeltaLVEF, DeltaLVESV, DeltaLVEDV and MPSI. The results showed that the LVEF obtained 3 months after revascularization in patients with MPSI>1.5 was obviously lower than that in those with MPSI<or=1.5. The LVEDV obtained 3 months post-revascularization in patients with MPSI>1.5 was obviously larger than that in those with MPSI<or=1.5 (P=0.002 and 0.04). The differences in DeltaLVEF and DeltaLVEDV between patients with MPSI>1.5 and those with MPSI<or=1.5 were significant (P=0.002 and 0.001, respectively). Linear regression analysis revealed that MPSI had a negative correlation with DeltaLVEF and a positive correlation with DeltaLVESV, DeltaLVEDV (P=0.004, 0.008, and 0.016, respectively). It was concluded that RT-MCE could accurately evaluate the left ventricular remodeling in patients with myocardial infarction after revascularization.

Intravenous contrast echocardiography after myocardial infarction: relationship among residual myocardial perfusion, contractile reserve and long-term remodelling

Previous studies have shown the potential role played by intracoronary myocardial contrast echocardiography (MCE) in predicting long-term remodelling and function after myocardial infarction (MI). Scanty data, however, are available on the role of intravenous MCE in this regard. The aim of this study was to assess the role of residual myocardial blood volume in the asynergic region in modulating ventricular volume changes over time post-MI. Thirty-two consecutive patients with anterior MI were studied predischarge using low-dose dobutamine echocardiography (Dob) and intravenous triggered MCE. Videointensity plots were generated from the apical approach and fitted exponentially. Volumes were assessed at baseline, during Dob and at 8 months. Baseline volumes, which appeared related to the extent of the asynergic region (P < 0.01) but showed no relation with videointensity in that area, did not change at follow-up, although Dob had elicited significant contractile reserve. However, videointensity in the asynergic region showed a significant interaction (P = 0.044) with the change in diastolic volume over time, with patients with the highest videointensity reverting remodelling (n = 11, from 69 +/- 16 to 65 +/- 16 ml/m) as compared with the remaining population (n = 21, from 68 +/- 16 to 73 +/- 21 ml/m). This was not seen when Dob-derived parameters were used. Multivariate analysis ranked videointensity second (P = 0.066), after baseline stroke volume (P = 0.005), in predicting changes in volumes over time. Unlike inotropic reserve, residual myocardial blood volume in the dysfunctioning muscle, as assessed by predischarge quantitative intravenous MCE, has the potential to modulate remodelling in patients who suffered an anterior MI.

Quantitative Assessment of Microcollateral Recruitment During Coronary Occlusion Using Real-time Intravenous Myocardial Contrast Echocardiography

Residual collateral-derived myocardial blood flow (MBF) (A x beta) is important to protect against myocardial ischemia after acute coronary occlusion. Recruitment of microcollateral was assessed in 22 dogs with left circumflex coronary artery occlusion by analysis of MBF and regional wall thickening (WT) using real-time myocardial contrast echocardiography. Video intensity and WT at the center of risk area were significantly lower than those at the border of risk area. The video intensity, A value, beta value, and MBF correlated well with WT after left circumflex coronary artery occlusion. The WT of the area with above 25% of normal MBF was preserved and was higher than that at below 25%. However, the deterioration of WT was not distinguished according to A value. Real-time myocardial contrast echocardiography is a useful noninvasive method to evaluate collateral-derived MBF, which can be a reliable index of protection against myocardial ischemia.

Assessment of intravascular and extravascular mechanisms of myocardial perfusion abnormalities in obstructive hypertrophic cardiomyopathy by myocardial contrast echocardiography

Objectives:To assess mechanisms of myocardial perfusion impairment in patients with hypertrophic cardiomyopathy (HCM).Methods:Fourteen patients with obstructive HCM (mean (SD) age 53 (10) years, 11 men) underwent intravenous adenosine myocardial contrast...

Quantification of Myocardial Perfusion Using Intravenous Myocardial Contrast Echocardiography in Healthy Volunteers: Comparison with Positron Emission Tomography

Intravenous myocardial contrast echocardiography (ivMCE) has the potential to evaluate myocardial contraction and perfusion simultaneously. The purpose of this study was to assess quantification of myocardial blood flow (MBF) using ivMCE and to compare this with MBF as measured with positron emission tomography (PET). A total of 16 healthy volunteers underwent ivMCE using power pulse inversion and contrast agent microbubbles at rest and during pharmacologically induced vasodilation. Microbubble destruction was achieved with a burst of high-energy ultrasound, followed by imaging of contrast replenishment with low-energy ultrasound. Regions of interest were drawn and time intensity curves were calculated that were fitted to a monoexponential function. An estimate of MBF (perfusion estime) was calculated as the product of the plateau value A and the exponential beta describing the replenishment curve. MBF was measured with PET using oxygen-15-labeled water at rest and during adenosine stress. Significant correlations were found between MBF as measured with PET and perfusion estimate as measured with ivMCE in the left anterior descending coronary artery (r = 0.87, P < .01), right coronary artery (r = 0.66, P < .01), and left circumflex artery (r = 0.75, P < .01) territories. Heterogeneity, however, was significantly larger for ivMCE (coefficient of variation 32 +/- 15%) than for PET (9 +/- 6%) measurements (P < .01). Perfusion parameters as measured with ivMCE correlated with PET-derived MBF, but associated heterogeneity was significantly larger. Currently, this heterogeneity precludes true quantification of MBF using ivMCE.

Assessment of Myocardial Perfusion With Intravenous Myocardial Contrast Echocardiography Current State and Clinical Applications

Assessment of Myocardial Perfusion With Intravenous Myocardial Contrast Echocardiography Current State and Clinical Applications

753 Real-time intravenous myocardial contrast echocardiography using low emission power is safe with respect to the occurrence of arrhythmias in healthy volunteers

753 Real-time intravenous myocardial contrast echocardiography using low emission power is safe with respect to the occurrence of arrhythmias in healthy volunteers

Intravenous Versus Intracoronary Myocardial Contrast Echocardiography for Evaluation of No‐Reflow After Primary Percutaneous Coronary Intervention

We sought to compare intravenous myocardial contrast echocardiography (IV-MCE) with intracoronary myocardial contrast echocardiography (IC-MCE) in detecting no-reflow and predicting the short-term outcome of left ventricular function after primary percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). IC-MCE and IV-MCE were performed immediately after PCI (D1) of 28 patients with anterior wall AMI. IV-MCE was repeated at the next day of PCI (D2), and left ventricular systolic function was evaluated at D2 and 30 days later (D30). There was good agreement between IC-MCE and IV-MCE at D1 in determining no-reflow (kappa= 0.78, P < 0.001) as well as between IV-MCE at D1 and D2 (kappa= 0.93, P < 0.001). The patients with no-reflow on IC-MCE (n = 13) and those on IV-MCE at D2 (n = 11) showed no improvement in left ventricular ejection fraction (LVEF) after 1 month (49 +/- 9% to 48 +/- 7%, P = 0.55, and 51 +/- 6% to 49 +/- 7%, P = 0.20). However, the patients with reflow on IC-MCE (n = 15) and those on IV-MCE at D2 (n = 17) demonstrated significant improvement in LVEF (55 +/- 6% to 62 +/- 5%, P < 0.005, and 53 +/- 7% to 60 +/- 8%, P < 0.005). In predicting segmental functional recovery after 1 month, sensitivity and specificity of IC-MCE were 85% and 67%, respectively, and those of IV-MCE at D2 were 95% and 40%, respectively. IV-MCE at D2 might be substituted for IC-MCE performed immediately after PCI for the evaluation of no-reflow and prediction of left ventricular systolic function after 1 month in patients with anterior wall AMI.

Intravenous myocardial contrast echocardiography for the diagnosis of coronary artery disease

Myocardial contrast echocardiography is a recently developed technique that permits the noninvasive assessment of myocardial perfusion. Myocardial contrast enhancement from microbubbles characteristically reflects the myocardial blood volume. The analysis of microbubble kinetics using quantitative myocardial contrast echocardiography permits the evaluation of myocardial blood flow both at rest and during pharmacological stress. Myocardial contrast echocardiography has been shown to have good concordance with single photon emission computed tomography for the localization of perfusion abnormalities. As a result of its better spatial resolution and the fact that it tracks myocardial blood flow changes, it seems to have higher sensitivity for the detection of angiographically significant coronary artery disease, while maintaining similar specificity to single photon emission computed tomography. Low mechanical index imaging techniques (real-time myocardial contrast echocardiography) have the advantage of permitting simultaneous analysis of wall motion and perfusion, which is particularly important during dobutamine stress. Myocardial perfusion analysis using real-time myocardial contrast echocardiography has been shown to have higher sensitivity and diagnostic accuracy than wall motion analysis for the detection of coronary artery disease. Quantitative myocardial contrast echocardiography seems to overcome the expertise requirements for appropriate interpretation of myocardial perfusion images, and may have been demonstrated to be an accurate supplemental technique for estimating the severity of coronary artery disease. Recent technological advances have positioned myocardial contrast echocardiography as a safe and feasible technique for the evaluation of myocardial perfusion. The analysis of myocardial perfusion using myocardial contrast echocardiography has higher diagnostic accuracy than wall motion analysis for detecting coronary artery disease.

Usefulness of quantitative intravenous myocardial contrast echocardiography to analyze microvasculature perfusion in patients with a recent myocardial infarction and an open infarct-related artery: comparison with intracoronary myocardial contrast echocardiography

We analyzed the usefulness of quantitative intravenous myocardial contrast echocardiography to study microvasculature perfusion after infarction in comparison with intracoronary myocardial contrast echocardiography. Thirty-two patients with a first ST elevation myocardial infarction, single-vessel disease and an open artery (TIMI 3) were studied before discharge. Myocardial perfusion in the risk area was quantified with intracoronary and intravenous myocardial contrast echocardiography. Perfusion was normal (intracoronary contrast echocardiography normalized videointensity >0.75) in 78 out of 97 dysfunctional segments (80%). Sensitivity and specificity of intravenous contrast echocardiography to predict normal perfusion were 87% and 63% for 'first-pass myocardial blood flow' (upslope of contrast arrival x peak intensity after intravenous bolus injection of contrast) and 91% and 89% for end-systolic single-triggered images captured every 6 cycles, respectively. In an analysis per patients, normal perfusion (0 or 1 hypoperfused segments with intracoronary contrast echocardiography) was observed in 22 cases (69%). End-systolic single-triggered images showed a strong correlation with intracoronary contrast echocardiography (R2 = 0.82, p = 0.0001). Intravenous contrast echocardiography is a useful technique to analyze microvasculature perfusion soon after infarction. A quantitative analysis of single-triggered images is an easy-to-obtain and reliable method to define perfusion when compared with intracoronary contrast echocardiography.

Usefulness of Real-Time Intravenous Myocardial Contrast Echocardiography in Predicting Left Ventricular Dilation After Successfully Reperfused Acute Myocardial Infarction

The ability of real-time intravenous myocardial contrast echocardiography to predict left ventricular remodeling after reperfused acute myocardial infarction was assessed in 47 patients. Intravenous myocardial contrast echocardiography was an independent predictor of left ventricular dilation after acute myocardial infarction. In particular, normal contrast opacification within dyssynergic segments indicated a very low risk of remodeling.

Efficacy of 1.5 Harmonic Imaging for Intravenous Myocardial Contrast Echocardiography

Background. Although second harmonic (2H) imaging is utilized to minimize the tissue signals in myocardial contrast echocardiography (MCE), the native tissue harmonic signal is sufficiently high enough to cause a misreading of myocardial opacification when high mechanical index (MI) is used.Purpose. The backscattered signal from microbubbles at high MI is broadband, while it is narrowband at low MI. Therefore, the bubble/tissue signal ratio is expected to be high between the fundamental signal and 2H frequencies at high MI. Our aim was to elucidate the efficacy of a new imaging method using an in-between frequency, denoted as 1.5 harmonic (1.5H) imaging.Methods. Six open-chest dogs were examined using Toshiba APLIO with 1.5H and conventional 2H system. The transmitting/receiving frequencies were 2.3/3.3 MHz for 1.5H and 1.4/2.8MHz for 2H imaging, respectively. Intermittent MCE was performed at a MI of 1.6 after injection of Levovist®, and baseline intensity and peak intensity of opacification of the ventricular septum were measured.Results. While baseline intensity of the septum was significantly lower using 1.5H than 2H (26±4 vs. 43±14 gray level, p<0.001), the opacification after Levovist was significantly higher using 1.5H than 2H (91±32 vs. 51±38, p<0.001). Due to the combination of these effects, visual recognition of myocardial opacification was quite superior with 1.5H imaging.Conclusion. The 1.5H imaging system provides superb contrast opacification when using high MI.

Evaluation of cardiac function and myocardial perfusion in small animals: Capability of echocardiography

Background Recently, there have been many studies on genes or regenerations using small animals such as mice and rats. However, the therapeutic effects in genes or cell levels were not always available in organs. The effects on organs were evaluated by pathologic examinations. Ultrasound, a noninvasive examination, was used to evaluate organs of small animals. However, it was very difficult to evaluate in detail because of limited resolution. The evaluation of hearts in small animals is very difficult due to rapid heart rate and small size. Purpose We would like to introduce the availability of echocardiography to evaluate the cardiac function and myocardial perfusion in small animals. Methods Fourteen open-chest rats were examined to evaluate myocardial perfusion. Intravenous myocardial contrast echocardiography (MCE) was performed by fundamental and intermittent mode using a high-frequency transducer with SONOS 5500 during injection of NC 1001000. We compared the area at risk by MCE with that by Evans blue staining. Result All wall segments were clearly opacified and the risk area was clearly observed in the cases where the left anterior descending coronary artery was ligated. There was a good correlation between the area at risk by MCE and that by Evans blue staining. Conclusion Intravenous myocardial contrast echocardiography can detect perfusion defects, even in rats, using a high-frequency transducer.

Myocardial microvascular abnormalities observed by intravenous myocardial contrast echocardiography in patients with hypertrophic cardiomyopathy

We tested the hypothesis that myocardial microvascular abnormalities occur and are influenced by clinical features in 30 patients with hypertrophic cardiomyopathy (HC) using intravenous myocardial contrast echocardiography. Patients with HC were subdivided into 3 groups: nonobstructive HC (n = 12), obstructive HC (n = 10), or HC with systolic dysfunction and heart failure (n = 8). In patients with nonobstructive HC and obstructive HC, subendocardial peak myocardial contrast intensity at the mid-septal area was significantly decreased and the transmyocardial difference of peak myocardial contrast intensity between subendocardial and periendocardial regions at the mid-septal area was significantly related to regional wall thickness. Reduced peak myocardial contrast intensities at the mid-septal subendocardial and periendocardial regions were observed in patients with HC and heart failure. Our study indicates that subendocardial microvascular abnormalities during end-systole may be associated with severity of regional myocardial hypertrophy in patients with nonobstructive HC and obstructive HC. In addition, progressive microvascular damage may occur in patients with HC and heart failure.