Cyclic Variation Of Integrated Backscatter Research Articles

Cyclic Variation of Spectral Parameters for the Differentiation of Atrial Myocardium Before and Immediately Following Radiofrequency Ablation.

Radiofrequency ablation (RFA) is a common treatment of atrial fibrillation. However, current treatment is associated with a greater than 20% recurrence rate, in part due to inadequate monitoring of tissue viability during ablation. Spectral parameters, in particular cyclic variation of integrated backscatter (CVIB), have shown promise as early indicators of myocardial recovery from ischemia. Our aim was to demonstrate the use of spectral parameters to differentiate atrial myocardium before and after radiofrequency ablation. An AcuNav 10 F catheter was used to collect radiofrequency signals from the posterior wall of the left atrium of patients before and immediately after RFA for AF. The normalized power spectrum was obtained and three spectral parameters (integrated backscatter [IB], slope, and intercept) were extracted across two continuous heart cycles. Parameters were gated for ventricular end-diastole and compared before and after ablation. Additionally, the cyclic variation of each of these three parameters was generated as an average of the variation across the two recorded heart cycles. Data from 14 patients before and after ablation demonstrated a significant difference in the magnitude of the cyclic variation of integrated backscatter (9.0 vs. 6.0 dB, p < .001) and cyclic variation of the intercept (14.0 vs. 11.5 dB, p = .04). No significant difference was noted in the magnitude of the cyclic variation of the slope. Among spectral parameters gated for end-diastole, significant differences were noted in the slope (-4.39 vs. -3.73 dB/MHz, p = .002) and intercept (16.8 vs. 11.9 dB, p = .002). No significant difference was noted in the integrated backscatter. Spectral parameters are able to differentiate atrial myocardium before and immediately following ablation and may be useful in monitoring atrial ablations.

Monitoring of atrial ablation using cyclic variation of integrated backscatter

Treatment of atrial fibrillation (AF) often relies on radiofrequency ablation (RFA) of atrial tissue. However, current treatment is associated with a &amp;gt;20% recurrence rate, in part due to inadequate monitoring of tissue viability during ablation. Previous work has utilized cyclic variation of integrated backscatter (CVIB) as an early indicator of myocardial recovery from ischemia. Our aim was to demonstrate the use of CVIB to distinguish normal and ablated myocardium. An AcuNav 10F catheter was used to collect radiofrequency signals from the posterior wall of the left atrium of patients before and after RFA for AF. The normalized power spectrum was obtained and integrated backscatter (IB) was extracted across two continuous heart cycles to calculate the average CVIB. Data from 14 patients demonstrated a significant difference in the magnitude of the CVIB before and after ablation (9.0 vs 6.0 dB, p &amp;lt; 0.001). However, no significant changes were identified when evaluating ECG-gated IB values before and after ablation: ventricular end-systole (−9.8 vs −8.6, p = 0.24), atrial end-diastole (−8.2 vs −8.6, p = 0.72) or ventricular end-diastole (−7.7 vs −8.9, p = 0.18). CVIB is able to differentiate normal and ablated myocardium and may be useful in monitoring atrial ablations.

Detection of early radiotherapy-induced changes in intrinsic myocardial contractility by ultrasound tissue characterization in patients with early-stage breast cancer.

Increased cardiovascular morbidity and mortality are major late complications after radiotherapy (RT) in the thoracic region. Ultrasound tissue characterization (UTC) is a noninvasive method for the identification of myocardial changes. The aim of this prospective clinical trial was to assess whether the analysis of cyclic variation of integrated backscatter (CVIBS) can detect early RT-induced myocardial alterations. Seventy-three eligible patients with early-stage breast cancer were evaluated before and immediately after adjuvant RT. Twenty and 53 patients had right-sided and left-sided breast cancer, respectively. None of the patients received chemotherapy. Comprehensive echocardiographic examination included three-dimensional (3D) measurements and UTC analysis of the left ventricular (LV) septum and posterior wall. RT reduced CVIBS in a dose-dependent manner. The mean heart radiation dose over two gray (Gy) reduced the septal CVIBS from 12.0±3.4 to 9.6±2.5 dB (P<.001) and the posterior wall CVIBS from 12.8±2.7 to 11.3±2.4 dB (P=.007). The CVIBS remained unchanged when the mean heart RT dose was below 2Gy. Multivariate analysis showed an independent association with a change in septal CVIBS and the use of aromatase inhibitor (β=2.986, P=.001) and body mass index (β=-0.241, P=.014). The posterior values were worse with higher mean lung dose (β=-.485, P=.018) and with nonsmoking status (β=-2.411, P=.009). Echocardiography parameters showed increased myocardial mass but conventional measurements of the LV systolic function remained unchanged. Cyclic variation of integrated backscatter analysis seems to be a sensitive method to detect early RT-induced myocardial changes. Hence, it may be useful in screening of patients needing closer follow-up.

Effects of 12 Weeks of Atorvastatin Therapy on Myocardial Fibrosis and Circulating Fibrosis Biomarkers in Statin-NaïVe Patients with Hypertension with Atherosclerosis

The purpose of this study was to assess the effects of 12 weeks of atorvastatin treatment on myocardial fibrosis in patients with hypertension with atherosclerosis. 15 statin-naïve participants (11 males; mean age 67±10 years) with atherosclerosis were given atorvastatin (40 mg/day) for 12 weeks and underwent echocardiography including ultrasonic tissue characterization by cyclic variation of integrated backscatter (CVIBS). Serum galectin-3 and fibrosis markers including aminoterminal propeptide of type III procollagen (PIIINP), matrix metalloproteinase-2, metalloproteinase-9, and tissue inhibitor of metalloproteinase-1 (TIMP-1) were also analyzed. After 12 weeks of atorvastatin (40 mg/day) treatment, serum total cholesterol and low-density lipoprotein cholesterol decreased significantly (204±31 to 140±24 mg/dL and 133±26 to 69±17 ng/mL, respectively, both p<0.001). In myocardial fibrosis analysis, CVIBS increased significantly (6.6±1.9 to 8.5±2.7 dB, p=0.024). In addition, the circulating fibrosis markers serum PIIINP and TIMP-1 decreased significantly (9.5±2.7 to 6.4±1.4 ng/mL, p=0.012 and 299±65 to 250±45 ng/mL, p=0.024, respectively). 12 weeks of medium dose atorvastatin treatment resulted in a significant reduction in myocardial fibrosis as evaluated by morphofunctional parameters and plasma markers of tissue fibrosis. NTC00172419; results.

Aldosterone induced galectin-3 secretion via MR/PI3K/Akt/NF-kB signaling in THP-1 cell: a possible mediator of myocardial fibrosis in patients with primary aldosteronism

Purpose: Patients with primary aldosteronism (PA) are associated with increased myocardial fibrosis. Galectin-3 is one of the most important mediators between macrophage activation and myocardial fibrosis. Our objective was to investigate aldosterone induced galectin-3 secretion and the association between galectin-3 and myocardial fibrosis in cell and human study. Methods: We investigated the possible molecular mechanism of aldosterone to induce galectin-3 secretion in THP-1 cell and the possible effect on fibroblast. Further, we conducted a prospective clinical study to evaluate the relation between plasma galectin-3 level and myocardial fibrosis (measured by cyclic variation of integrated backscatter (CVIBS)) in patients with aldosterone producing adenoma (APA) and patients with essential hypertension (EH). Repeated measurement was performed in APA patents one year after adrenalectomy. Result: Aldosterone induced gelactin-3 secretion in the THP-1 cell and the pathway was through the mineralocorticoid receptor. The induced secretion occurs via the PI3K/Akt pathway, and through the NF-κB transcription pathway. Furthermore, aldosterone induced galectin-3 expression enhanced fibrosis related factor expression in fibroblast.Patients with APA had a significant higher plasma galectin-3 level and lower CVIBS data than EH. The plasma galectin-3 level is significantly reversely correlated with CVIBS data. One year after adrenalectomy, the plasma galectin-3 level decreased and CVIBS data increased significantly in APA patients. Conclusion: Aldosterone induced galectin-3 formation in THP-1 cell and further increased myocardial fibrosis. These findings suggest galectin-3 plays an important role on the pathogenesis of aldosterone-induced myocardial fibrosis.

Diagnostic performance of ultrasonic tissue characterization for subendocardial ischaemia in patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) patients often develop left--ventricular subendocardial ischaemia, a cause of chest symptoms, despite normal epicardial coronary arteries. The aim of this study was to examine whether ultrasonic tissue characterization or late gadolinium enhancement on cardiac magnetic resonance imaging can detect subendocardial ischaemia in patients with HCM. Subendocardial ischaemia was quantified on exercise Tc-99m tetrofosmin myocardial scintigraphy in 29 non-obstructive HCM patients with asymmetric septal hypertrophy. Ultrasonic tissue characterization using cyclic variation of integrated backscatter (CV-IB) and late gadolinium enhancement on cardiac magnetic resonance imaging were analysed separately in the right halves and the left halves of the ventricular septum in relation to subendocardial ischaemia. Subendocardial ischaemia was identified in 17 (59%) patients. The ratio of CV-IB in the right-to-left halves of the ventricular septum was significantly higher in patients with subendocardial ischaemia (1.19 ± 0.10) than those without (0.84 ± 0.10, P = 0.04). The optimal cutoff for the detection of subendocardial ischaemia was the ratio of CV-IB >1.0, with a sensitivity of 80%, specificity of 71%, and accuracy of 76%. On the other hand, late gadolinium enhancement was not associated with subendocardial ischaemia in our cohort. Ultrasonic tissue characterization using CV-IB separately in the right and left halves of the ventricular septum, but not late gadolinium enhancement on magnetic resonance imaging, provided useful information in detecting subendocardial ischaemia in patients with HCM. Ultrasonic tissue characterization may be useful in selecting patients who will benefit from medications to relieve chest symptoms.

Myocardial Ultrasound Tissue Characterization of Patients With Primary Aldosteronism

Primary aldosteronism (PA), an underdiagnosed cause of hypertension, is associated with more significant cardiac remodeling and myocardial fibrosis than is essential hypertension (EH). The aim of this study was to validate myocardial fibrosis and to evaluate factors associated with the degree of myocardial fibrosis in patients with PA. We prospectively analyzed 62 patients with PA (including 46 patients with aldosterone-producing adenoma and 16 with bilateral hyperplasia) between October 2006 and October 2010, and we enrolled 17 patients with EH as the control group. Echocardiography, including ultrasonic tissue characterization using cyclic variation of integrated backscatter (CVIBS), was performed in individuals in both groups. Among patients with PA, the diastolic blood pressures and plasma aldosterone concentrations were significantly higher than those of patients with EH. Moreover, the serum potassium levels and the plasma renin activities were significantly lower in patients with EH. As observed by echocardiography, patients with PA had greater interventricular septal thickness, greater left ventricular posterior wall thickness, and higher left ventricular mass indexes than did patients with EH. Patients with PA had significantly lower CVIBS values than patients with EH (7.1 ± 2.2 vs. 8.7 ± 1.5 dB; p = .005). In a correlation study that corrected for various clinical parameters, only log-transformed plasma renin activity values correlated significantly with CVIBS values. Ultrasonic tissue characterization with CVIBS is a useful tool for determining the extent of myocardial fibrosis. Patients with PA exhibit a more severe degree of myocardial fibrosis, as detected by CVIBS, than do patients with EH. Moreover, the severity of fibrosis, as detected by CVIBS, correlates with log-transformed plasma renin activity values.

Prediction of preclinical myocardial damage utilizing cardiac biomarkers and ultrasound myocardial tissue characterization by integrated backscatter in patients with breast cancer treated with postoperative adjuvant radiotherapy.

169 Background: To evaluate whether cardiac biomarkers, ultrasonic integrated backscatter (IBS) can predict early myocardial damage in breast cancer patients treated with postoperative adjuvant radiotherapy. Methods: Forty-eight left-sided breast cancer patients treated with modified radical mastectomy and non-anthracycline containing chemotherapy regimen were examined. Baseline blood samples were drawn for cardiac markers analysis, including Troponin T (TnT), C-reactive protein (CRP), and brain natriuretic peptide (BNP). Calibrated myocardial IBS (CMIBS, assessed by comparison of the anterior wall (AW), inferior wall (IW), anteroseptum (AS) and posterior wall (PW) with pericardial IBS intensity), cyclic variation of IBS (CVIBS) and conventional echocardiography parameters (LVIDd: the left ventricular internal diameter at end-diastole; IVSTd: the intraventricular septal thickness at end-diastole; PWTd: the posterior wall thickness at end-diastole; LVDs: the left ventricular end-systolic dimension; EF: the left ventricular ejection fraction; FS: the left ventricular fractional shortening. The peak velocity of early (E) and late ventricular filling (A) were also determined for calculating the ratio E/A) were investigated before the initiation of radiotherapy (group A), during (group B, 3 weeks after the initiation, the cumulative dose was about 30Gy) and after radiotherapy (group C, 5 weeks, the cumulative dose was about 50Gy). At each time point, blood was drawn to measure TnT, CRP, and BNP. Results: TnT, CRP, and BNP did not change over time. CMIBS of AW and AS were significantly increased after radiotherapy both during (group B, p&lt;0.05) and at the end of treatment (group C, p&lt;0.01) and meanwhile CVIBS and E/A were decreased significantly throughout the treatment period (group B, p&lt;0.05 for both; group C, p&lt;0.01 for both) compared with the beginning (group A). Conclusions: Myocardial IBS offers a promising approach for early clinical detection and characterization of evolution of cardiomyopathy induced by radiotherapy in breast cancer patients.

Adrenalectomy reverses myocardial fibrosis in patients with primary aldosteronism

Primary aldosteronism is the most frequent cause of secondary hypertension and is associated with more prominent left ventricular hypertrophy and increased myocardial fibrosis. However, the reversibility of cardiac fibrosis is still unclear. Our objective was to investigate myocardial fibrosis in primary aldosteronism patients and its change after surgery. We prospectively analyzed 20 patients with aldosterone-producing adenoma (APA) who received adrenalectomy from December 2006 to October 2008 and 20 patients with essential hypertension were enrolled as the control group. Plasma carboxy-terminal propeptide of procollagen type I (PICP) determination and echocardiography including ultrasonic tissue characterization by cyclic variation of integrated backscatter (CVIBS) were performed in both groups and 1 year after operation in the APA group. APA patients had significantly higher SBP and DBP, higher plasma aldosterone concentration (PAC), higher aldosterone-renin ratio (ARR), lower serum potassium levels, and lower plasma renin activity (PRA) than patients with essential hypertension. In echocardiography, APA patients had a higher left ventricular mass index than essential hypertension patients. APA patients had significantly lower CVIBS (6.2 ± 1.5 vs. 8.7 ± 2.0 dB, P < 0.001) and higher plasma PICP levels (107 ± 27 vs. 85 ± 24 μg/l, P = 0.009) than essential hypertension patients. In the correlation study, CVIBS is correlated with log-transformed PRA and log-transformed ARR and PICP is correlated with log-transformed PRA, log-transformed PAC, and log-transformed ARR. One year after adrenalectomy, CVIBS increased significantly (6.2 ± 1.5 to 7.3 ± 1.7 dB, P = 0.033) and plasma PICP levels decreased (107 ± 27 vs. 84 ± 28 μg/l, P = 0.026). Increases in collagen content in the myocardium of APA patients may be reversed by adrenalectomy.

A-005 MYOCARDIAL ULTRASOUND TISSUE CHARACTERIZATION IN PATIENTSWITH PRIMARY ALDOSTERONISM

Background Primary aldosteronism (PA), an underdiagnosed cause of hypertension, causes cardiac remodeling and myocardial fibrosis. Ultrasonic tissue characterization by cyclic variation ofintegrated backscatter(CVIBS) is a useful tool to evaluate the extent of myocardial fibrosis. The aim of this study is to assess the myocardial fibrosis caused by primary aldosteronism and to evaluate the relationship among CVIBS and baseline clinical parameters of PA patients. Methods We prospectively analyzed 62 patients with PA (including 46 patients with aldosterone-producing adenoma and 16 with bilateral hyperplasia) from October 2006 to October 2010, and 17 patients with essential hypertension (EH) were enrolled asthe control group. Echocardiography, included ultrasonic tissue characterization by CVIBS, was performed in both groups. Results In patients with PA, diastolic blood pressure and plasma aldosterone concentration were significantly higherthan patients with EH. Meanwhile, serum potassium level and plasma renin activity were significantly lower than patients with EH. In echocardiography, patients with PA had thickerinterventricularseptal thickness, left ventricular posterior wall thickness, and higher left ventricularmass index than EH patients. Patients with PA had significant lower CVIBS than EH patients (7.1 ± 2.2vs 8.7 ± 1.5 dB, P = .005). In correlation study, among various clinical parameters, only log-transformed plasma renin activity was correlated significantly with CVIBS. Conclusion Ultrasonic tissue characterization with CVIBS is a useful tool to detect the extent of myocardial fibrosis. PA patients have more severe degree of myocardial fibrosis detected by CVIBS. The severity of fibrosis detecting by CVIBS is correlated with log-transformed plasma renin activity.

U-006 REVERSAL OF MYOCARDIAL FIBROSIS AND DIASTOLIC DYSFUNCTION IN PATIENTS WITH ALDOSTERONE PRODUCING ADENOMA RECEIVING ADRENALECTOMY

Background Primary aldosteronism (PA) is the most frequent cause of secondary hypertension, and is associated with more prominent left ventricular hypertrophy, increased myocardial fibrosis and diastolic dysfunction. Aldosterone producing adenoma (APA) can be cured by adrenalectomy. However, the reversibility of cardiac structure and function still unclear. Method We prospectively analyzed 17 patients withAPA that received adrenalectomy from October 2006 to Oct 2008and 11 patients with essential hypertension (EH) were enrolled as the control group. Echocardiography included including tissue Doppler image (TDI) and ultrasonic tissue characterization by cyclic variation of integrated backscatter (CVIBS) were performed in both groups and one year after operation in unilateral hyperaldosteronism group. Besides, markers of cardiac tissue collagen turnover, including plasma carboxy-terminal propeptide of procollagen type I (PICP) and matrix metalloproteinase-2 (MMP-2) were also checked. Results Patients with APA had significantly higher diastolic blood pressure, higher plasma aldosterone concentration, lower serum potassium level, and lower plasma renin activity (PRA) than patients with EH. In echocardiography, patients with APA had higher left ventricular mass index (LVMI) than EH patients. In the TDI study, APA patients had lower early diastolic velocity (e’) than EH (6.7 ± 1.2 vs.8.9 ± 1.7, p = 0.003 in septal mitral annulus and 7.8 ± 3.0 vs.11.2 ± 2.7, p < 0.001 in lateral mitral annulus). In cardiac tissue character analysis, APA patients had significant lower CVIBS than EH patients (6.7 ± 1.9 vs.9.1 ± 1.7 dB, p = 0.003). In collagen turnover markers, APA patientshad higher plasma PICP, but not MMP-2 than EH patients (PICP: 105 ± 26 vs. 81 ± 28 μg/L, p = 0.03, MMP-2: 223 ± 90 245 ± 63 ng/ml, p = 0.462). One year after adrenalectomy, LVMI decreased significantly. In addition, early diastolic velocity(e’) in TDI study and CVIBS increased significantly after adrenalectomy (p = 0.001 for septal e’; p = 0.012 for lateral e’; p = 0.019 for CVIBS). Plasma PICP also decreases significantly (p = 0.030) after operation. Conclusion Adrenalectomy reverses not only left ventricular geometry but also altered myocardial texture and improve cardiac diastolic function in APA patients. This implies that increases in collagen content in the myocardium of APA patients may be reversed by adrenalectomy.

Relationship between ultrasonic tissue characterization and myocardial deformation for prediction of left ventricular reverse remodelling in non-ischaemic dilated cardiomyopathy

This study was to evaluate the relationship between ultrasonic tissue characterization by integrated backscatter (IBS) and myocardial deformation assessed by two-dimensional speckled tracking (2DS) imaging for prediction of left ventricular (LV) reverse remodelling in patients with non-ischaemic dilated cardiomyopathy (DCM). Forty-five consecutive patients with non-ischaemic DCM were enrolled prospectively. The mean cyclic variation of integrated backscatter (CVIBS) was calculated as the mean of the septal and posterior wall CVIBS. LV global longitudinal, radial, and circumferential peak strain (GLS, GRS, and GCS, respectively) and twist were obtained. LV reverse remodelling was decided with follow-up echocardiography 12 months. The GLS, GRS, and GCS were correlated with the mean CVIBS. The mean CVIBS and GCS were significantly larger in the 24 patients who had LV reverse remodelling than the 21 patients who had no LV reverse remodelling and the GRS tended to be larger; the GLS and twist did not differ between the two groups. The mean CVIBS and GCS were independent predictors of LV reverse remodelling. Myocardial deformation assessed by 2DS was related to myocardial fibrosis assessed by IBS. LV reverse remodelling was predicted by mean CVIBS and GCS in patients with non-ischaemic DCM and GCS assessed by 2DS imaging is a simple method and therefore it can be readily used in clinical practice.

Three-layer ultrasonic tissue characterization of the ventricular septum is predictive of prognosis in patients with non-obstructive hypertrophic cardiomyopathy

A necropsy study of patients with hypertrophic cardiomyopathy (HCM) who died at a young age exhibited marked disarray and fibrosis in the mid-wall layer of the left ventricular (LV) myocardium. We assessed ultrasonic tissue characteristics in the three layers of the ventricular septum (VS), and correlated the result with long-term prognosis in HCM. The magnitude of cyclic variation of integrated backscatter (CV-IB) was calculated in the three layers of the VS and the whole aspect of the LV posterior wall in 58 non-obstructive HCM patients and 20 healthy controls. All HCM patients were prospectively followed for an average period of 7.1 years for the occurrence of cardiac death or hospitalization due to heart failure. Each CV-IB of four regions was lower in HCM patients than in controls (all P < 0.01). CV-IB of the VS mid-wall layer was lower in 14 HCM patients with cardiac events than in patients without (5.4 ± 0.6 vs. 7.4 ± 0.5 dB, P = 0.033) although CV-IB of three other regions did not differ between the two groups. The optical cut-off point of %CV-IB <90%, i.e. the ratio of CV-IB in the VS mid-wall layer to the mean value in the layers on both sides, was an independent predictor of cardiac events (hazard ratio, 6.12; 95% confidence interval, 1.62-66.6; P = 0.013), with a positive predictive value of 44% and particularly with a high negative predictive value of 91%. Patients with non-obstructive HCM are not likely to undergo cardiac events in the near future, when the CV-IB value is not significantly lower in the VS mid-wall layer than in the layers on both sides.

Early Myocardial Dysfunction After Chronic Use of Anabolic Androgenic Steroids: Combined Pulsed-Wave Tissue Doppler Imaging and Ultrasonic Integrated Backscatter Cyclic Variations Analysis

The chronic consumption of androgenic anabolic steroids (AAS) has shown to cause subclinical impairment of myocardial function. Pulsed-wave Doppler tissue imaging (PWDTI) detects early regional alterations of ventricular function, whereas integrated backscatter cyclic variations (IBScv) are tightly related to the contractile efficiency of the left ventricular wall. The aim of this study was to identify the effects of chronic AAS misuse on myocardial function using both PWDTI and IBScv. Twenty-eight male bodybuilders (11 AAS users, 17 AAS nonusers) and 20 healthy sedentary subjects (controls), matched according to age, were studied. To assess left ventricular function, each subject underwent standard Doppler echocardiography, PWDTI, and IBScv analyses. Left ventricular mass was significantly higher in AAS users than in AAS nonusers and controls. Global systolic function (assessed by determining the ejection fraction) was similar in all subjects, but isovolumetric relaxation time was significantly higher in AAS users than in controls. On PWDTI analysis, AAS users showed regional systolic and diastolic dysfunction (evaluated by measuring s', e', and a') not detectable in the other two groups. IBScv identified regional systolic impairment only in AAS users at the level of the left ventricular inferior wall. The present study confirms that in AAS users, PWDTI and IBScv are effective and reliable noninvasive diagnostic tools for detecting early abnormalities of the systolic and diastolic longitudinal myocardial function, probably related to an increase in myocardial collagen content, interpretable as a repair process against the direct cellular injury produced by AAS.

Comparison of Ischemic Side Effects of Levosimendan and Dobutamine with Integrated Backscatter Analysis

Levosimendan improves cardiac contractility without increasing oxygen consumption. However, its effects on ischemia were not supported with the utilization of a noninvasive parameter of myocardial characterization. The changes observed in integrated backscatter (IBS) may be reflective of change in myocardial ischemia. In this study, the effect of levosimendan on ischemia detected by IBS was evaluated in patients with ischemic heart failure (HF). Patients who had LVEF < 40% and NYHA III-IV symptoms of HF were included in this study. Patients were randomized to levosimendan (n = 21), or to dobutamine (n = 25) groups. The cyclic variation of integrated backscatter (CVIBS) was determined as the difference between the maximal and minimal values in a cardiac cycle, average of three consecutive beats. CVIBS was taken from the mid-anteroseptal, mid-inferior, and mid-posterolateral areas of the parasternal short axis images before the drug administration and at the end of the 24-hour infusion period. Baseline characteristics and concomitant medications were similar in both groups. A significant reduction in CVIBS was detected in anteroseptal (7.6 +/- 1.4 dB versus 5.9 +/- 0.8 dB, p = 0.01), inferior wall (7.4 +/- 0.8 dB versus 6.7 +/- 1.5 dB, p = 0.03), and posterolateral wall (9.0 +/- 1.2 dB versus 8.2 +/- 0.6 dB, p = 0.04) after dobutamine administration, while no significant changes were observed in the levosimendan group in all walls. Unlike dobutamine, levosimendan may not induce myocardial ischemia as shown by CVIBS at commonly used dosages in the setting of decompensated HF without active ischemia.

Comparison of the effects of new and conventional hormone replacement therapies on left ventricular diastolic function in healthy postmenopausal women: a Doppler and ultrasonic backscatter study

We aimed to compare the effects of new treatment modalities to conventional hormone replacement therapy (HRT) on left ventricular (LV) diastolic function, by means of conventional and tissue Doppler echocardiography and the myocardial integrated backscatter (IBS) in postmenopausal women. One hundred and fifty healthy postmenopausal women were included in this study. Subjects were assigned to one of the five groups receiving 1 year of treatment (estrogen, estrogen plus progesterone, raloxifene, tibolone or placebo). E and A wave velocity, E/A ratio, isovolumic relaxation time (IVRT), deceleration time (DT), peak early (Em) diastolic mitral annular velocity, E/Em ratio, the cyclic variation of integrated backscatter (CVIBS) and the mean value of the IBS signal (MIBS) were determined before and 12 months after therapy. E (76 +/- 10 vs. 98 +/- 8 cm/s, P = 0.0001 and 78 +/- 10 vs. 90 +/- 12 cm/s, P = 0.02, respectively), Em (14.3 +/- 2.4 vs. 16.4 +/- 2.5 cm/s, P = 0.001 and 15.1 +/- 3.4 vs. 16.2 +/- 3.5 cm/s, P = 0.01, respectively), and E/A ratio (1.15 +/- 0.3 vs. 1.42 +/- 0.4, P = 0.0001 and 1.0 +/- 0.2 vs. 1.22 +/- 0.2, P = 0.01, respectively) were increased significantly compared to pretreatment in both estrogen and raloxifene groups while DT, A, E/Em, and IVRT were significantly decreased. A significant increase in CVIBS and decrease in MIBS were detected 12 months after estrogen and raloxifene administration while no significant changes were observed in other groups. Changes in the MIBS and CVIBS were found to be independently associated with the observed changes in the diastolic function indexes during therapy. Both estrogen and raloxifene regimens may improve LV diastolic functions in healthy postmenopausal women. This improvement may be a result of direct cardiac effects on LV myocardium.

A two-dimensional CVIB imaging system with a speckle tracking algorithm

Quantitative ultrasound tissue characterization based on integrated backscatter (IB) has shown great potential in detecting myocardial ischemia. The magnitude of the cyclic variation in IB (CVIB) has been considered one promising parameter in assessing regional myocardial contractile performance. This lab has previously developed a novel ultrasonic fusion imaging method based on CVIB. However, the major problem for clinical applications of this technique is that the myocardial tissue could not be tracked effectively without cardiologist’s intervention. This paper introduced a speckle tracking method into the CVIB-weighted imaging system, called speckle tracking algorithm with adaptive window size (STAWAWS), to track myocardial tissue particle automatically. This method provides a way to obtain the particle’s positions frame by frame in a series of B-mode images. Then using the RF signals according to the particle’s positions the IB curve can be calculated to produce CVIB value. The method was applied on the experimental and clinical data cases’s analysis. The results of dog’s data processing showed that this method could eliminate the misunderstanding of myocardial ischemia especially near the endocardium. The results of clinical data suggested that this method had clinical significance in detecting ischemic myocardium. Though the CVIB-weighted images obtained by the use of this auto-tracking method can improve the accuracy of detecting myocardial ischemia, it is not real-time analysis and the clinical data cases are not sufficient. Further clinical validation is still needed in the future’ work.

Very Early Stage Detection of Acute Myocardial Infarction by Harmonic Ultrasonic Integrated Backscatter

To study the very early diagnosis of acute myocardial infarction (AMI) by harmonic imaging ultrasonic integrated backscatter (IBS). Thirty normal persons, 68 cases with AMI, of whom 28 cases were at the very early stage of acute myocardial infarction (in 2 h), and 40 cases with acute myocardial infarction (in 2 to 12 h) were examined by IBS and the cyclic variation of integrated backscatter (CVIB) with HP-5500 ultrasonic system in different segment (the segment of myocardial infarction and no myocardial infarction). In the segment of AMI of the very early stage (in 2 h) the IBS (dB) is much higher than that of the segment of no AMI (18.7 versus 8.3), p < 0.001, the CVIB (dB) are lower (6.1 versus 7.6), p < 0.001. But at that time there are no obvious changes in ECG. In the other 40 cases with AMI in 2 to 12 h, IBS in the segment of AMI is obviously higher than the normal person and no infarction segment in the same heart (21.3:8.3, 20.2:8.5) p < 0.05, but CVIB (dB) is obviously lower than the normal person and no infarction segment in the same heart (5.8:7.6, 5.9:9.4) p < 0.05 the changes of the ultrasonic is coincidence with ECG. IBS (dB) are very obvious just as in ECG. The result demonstrates that ultrasonic tissue characterization with harmonic imaging integrated backscatter can be used for diagnosis in the very early stage of AMI, and can judge the segment range of AMI and function of the whole heart. (E-mail: wuxiaoqing48@hotmail.com)

A Two-Dimensional CVIB Imaging System with a Snake-Based Tracking Algorithm

Quantitative ultrasound tissue characterization based on integrated backscatter (IB) has shown great potential in detecting myocardial ischemia. The magnitude of the cyclic variation in IB (CVIB) has recently been considered as one of the most promising parameters in assessing regional myocardial contractile performance. Our laboratory previously developed a novel ultrasonic fusion imaging method based on the CVIB. However, the major problem for clinical applications of this technique and other existing analytical methods based on IB is that the myocardial tissue can't be traced effectively without the cardiologist's intervention. In order to solve this problem, this paper presents a snake-based tracking algorithm to trace myocardial tissue automatically. A mathematical method is also introduced to extend the application of the snake model for detecting non-closed contours. The system developed in our previous research was redesigned to synchronize the radio frequency signal, the electrocardiographic signal, and the video signal, which allows verification of the system. Our results suggest that the system using the auto-tracking method increases the accuracy of detecting myocardial ischemia.

Objective Ischemic Evidence in Patients with Myocardial Bridging: Ultrasonic Tissue Characterization with Dobutamine Stress Integrated Backscatter

In this study, we investigated the sensitivities of dobutamine stress echocardiography (DSE) and integrated backscatter (IBS) in detecting ischemia in patients with symptomatic myocardial bridging (MB). Fourteen patients given the diagnosis of MB in the left anterior descending coronary artery as shown by coronary angiography were enrolled. All patients underwent DSE and stress IBS. The cyclic variation of IBS (CVIBS) was taken from the midanteroseptal, midinferior, and midposterolateral areas of the parasternal short-axis images at rest, low dose, peak dose, and recovery. The low-dose, peak-dose, and recovery CVIBS data were compared with baseline values. At peak dose, hypokinesia was observed in the left anterior descending coronary artery region in two patients (14%). A significant reduction in CVIBS was detected only when compared with the baseline at peak dose in the anteroseptal wall (8.4 +/- 1.3 vs 5.9 +/- 0.8, P = .003). A significant negative correlation was found between the CVIBS and the systolic narrowing percentage (R = -0.856, P = .001) and the length of MB (R = -0.576, P = .01) in the anteroseptal wall at peak dose. Whereas DSE is not sufficiently sensitive in the detection of ischemia in patients with symptomatic MB, the reduction in CVIBS during DSE may be an objective sign of ischemia.