利用超音波組織特性圖分析換心人心肌細胞的變化:與病理變化之比較

在換心後,心肌細胞的肥厚與組織間纖維元 的沉積會發生,並且對心臟功能產生影響。 我們認為加成性超音波逆行散射能偵測這些細胞變化。一共32 位無或僅具極輕微排斥的換心人接受加成性超音波逆行散射、鉈-201 心肌灌流掃描、心導管及心肌切片檢查。只有一位病人有彌漫性冠狀動脈狹窄;這位病患的加成性超音波逆行散射及鉈 -201 心肌灌流掃描也是異常。其餘31 位具正常冠狀動脈攝影的換心人中,有19 位加成性超音波逆行散射呈異常,16 位鉈-201心肌灌流掃描異常。有44%病患呈心肌細胞的肥厚及56%病患呈組織間纖維元的沉積。在異常與正常加成性超音波逆行散射 這兩組換心人中, 異常鉈-201 心肌灌流掃描比例及環孢靈素(cyclosporine)血清濃度有統計學之差異。病理變化與異常加成性超音波逆行散射也有明顯相關(p=0.01)。多變項回歸分析,異常加成性超音波逆行散射與環孢靈素血清濃度呈負相關(p=0.028) 。 結論: 異常加成性超音波逆行散射與心肌灌流之不均質性與心肌病理變化有相關。加成性超音波逆行散射對換心病患提供了一個新的非侵襲性檢查。Cardiomyocyte hypertrophy and interstitial fibrin deposition develop in cardiac allografts and contribute to the functional changes of transplanted hearts. We hypothesized that integrated backscatter (IBS) can detect these myocardial changes. A total of 32 heart transplant recipients with either no or mild acute rejection (International Society of Heart and Lung Transplantation grade IA) were enrolled in this study. IBS data of myocardium were collected immediately prior to dobutamine stress thallium-201 imaging. Coronary angiography and endomyocardial biopsy were also performed. Coronary angiography showed diffuse narrowing in 1 patient who also had abnormal results of IBS and thallium results. In the other 31 patients with patent coronary arteries, there were 19 patients (61%) with abnormal IBS patterns and 16 patients (52%) with reversible thallium perfusion defects. There were 44% patients with cardiomyocyte hypertrophy and 56% with interstitial fibrin deposition. There were significant differences in the prevalence of thallium-201 perfusion defects and serum cyclosporine levels between patients with and without abnormal IBS patterns. Pathological changes were also associated with abnormal IBS patterns (p = 0.01). By multiple logistic regression analysis, the abnormal IBS patterns were associated inversely with serum cyclosporine level (p = 0.028). In conclusion, abnormal IBS patterns are associated significantly with perfusion heterogeneity and pathological changes in heart transplant recipients without evident acute myocardial rejection. IBS provides a noninvasive approach for detection of myocardial changes in transplanted hearts without evident acute rejection

用杜卜勒超音波,超音波組織特性圖與鎝-99同位素心室造影來分析高血壓病患舒張功能之變化- 與心肌纖維化的血

越來越多的研究顯示心肌纖維化在高血壓 心臟變化中扮演了相當重要的角色。利用 免疫組織化學呈相法顯示在高血壓心臟病 的患者，其心臟間質及冠狀動脈週圍有大 量的第一類及第三類纖維膠原沉積。大量 的心臟纖維化會導致心室舒張功能異常。 在各種人體有關心臟纖維化的病理研究中 發現: 心肌細胞的超音波反射度與膠原堆 積的量有相當程度的關聯性。因此對研究 心肌纖維化而言; 加成性超音波逆行散射 (週期變化與波幅大小的改變)便成為一種 優良的非侵襲性工具。另一方面，膠原纖 維原分解的過程中會釋放一些物質如第一 類膠原纖維原碳基端分解物(PIP)、第三類 膠原纖維原胺基端分解物(PIIIP)至血清 中。據研究顯示，這些血清中的膠原纖維 分解物與心肌纖維化有關。在肝功能正常 的前提下，這些血清中的膠原纖維分解物 與組織中膠原纖維製造有量化性的相關。 因此我們設計這個研究；利用用杜卜勒超 音波,超音波組織特性圖與鎝-99 同位素心 室造影來分析高血壓病患舒張功能之變 化；並分析這些舒張功能變化與心肌纖維 化的血清標記之相關。這個研究目的有(1) 定量這些病患血清中的膠原纖維分解物 (PIP 與PIIIP)之數值；(2) 比較這些病患 左心室加成性超音波逆行散射(週期變化 與波幅大小的改變) 、杜卜勒超音波左心 室舒張功能評估[等容性左心室舒張時間 (isovolumetric relaxation time); 二尖瓣血 流速度與減速時間 (mitral flow velocities and deceleration time);肺靜脈血流的速度 與速度時間積分面積等與血清中的膠原纖 維分解物(PIP 與PIIIP)之相關; (3) 比較病 患鎝99 心室造影舒張功能異常與血清中 的膠原纖維分解物(PIP 與PIIIP)之相關。 共有22 名高血壓病患進入本研究。將 PINP 以35ug/l 作界線將病人分成兩組(第 一組 7 人，其PINP 濃度為24 ±8 ug/l 、第 二組15 人，其PINP 濃度為66 ±17 ug/l) 來分析舒張功能檢查的結果。PIIINP(3.8 ± 1.4vs 4.8 ±1.5 ug/l)、左心室大小(LVEDD 40 ±6 vs 43 ±4 mm/ LVESD 25 ±4 vs 26 ±3 mm)、二尖瓣血流參數(E/A ratio 0.7 ±0.2 vs 0.8 ±0.2; deceleration time 229 ±59 ms vs 217 ± 49ms)、肺靜脈血流參數 (retrograde A wave 32 ±4 cm/s vs 37 ±7 cm/s; 收縮血流 59 ±5 cm/s vs 67 ±14 cm/s; 舒張血流 37 ±6 cm/s vs 46 ±10 cm/s)、等容性左心室舒張時間86 ±14 ms vs 84 ±17 ms 、Tei index (0.5 ±0.0 vs 0.5 ± 0.1)、超音波組織特性圖 (amplitude 6.7 ± 3.1 vs 7.4 ±2.2db)等在兩組間均無差異。核 醫檢查則有明顯差異: peak filling rate of LV (3.4 ±0.8 vs 2.5 ±0.6 EDV/s; p=0.009); time to peak filling rate of LV 272 ±130 ms vs 176 ±72 ms; p<0.05]。PIIINP 則與 舒張功能無相關。結論: 高血壓病患超音波 逆行散射波幅、杜卜勒血流參數與膠原纖 維分解物PINP 與PIIINP 無明顯相關，但 鎝-99 心肌造影之舒張功能異常參數(peak filling rate of LV; time to peak filling rate of LV)與膠原纖維分解物PINP 有相關而與 PIIINP 無關。A growing body of evidence indicates that myocardial fibrosis is one of the key pathologic features of myocardial remodeling in hyperensive heart disease. An exaggerated accumulation of collagens type I and type III within the myocardial interstitium and surrounding intramural coronary arteries and arterioles has been evidenced immunohistologically in patients with hypertensive heart disease. Myocardial fibrosis predisposes to diastolic dysfunction of ventricle which, in turn, confer increased risk of adverse cardiovascular events to patients with hypertension. To determine the extent of collagen accumulation in tissue may be relevant in assessing the clinical outcome of these patients and in designing strategies to prevent its appearance or even to cause its regression. Studies performed in human with different pathologic conditions involving myocardial fibrosis have shown a promising correlation between echo-reflectivity and histologically assessed collagen content. Therefore, cyclic variation of in returning ultrasound signal intensity (cyclic variation of integrated backscatter) turns to be a non-invasive tool for measurement of myocardial fibrosis. On the other hand, serum procollagen type I carboxy-terminal peptide (PIP) and procollagen type III amino terminal peptide (PIIIP) have been related to myocardial fibrosis. Serum PIP and PIIIP concentration can be considered as a useful marker of myocardial collagen type I and III synthesis in conditions of preserved liver function. Therefore, we assessed the diastolic dysfunction of hypertensive patients. The parameter for diastolic dysfunction included mitral flow, pulmonary venous flow, Tei index, integrated backscatter and Tc-99m ventricular function assay. This prospective study was designed (1) to analyze the relation between myocardial integrated backscatter and serum markers (PIP and PIIIP) of myocardial fibrosis (2) to analyze the relation between myocardial Tc-99m imaging and serum markers (PIP and PIIIP) of myocardial fibrosis (3) to analyzed the relation among mitral flow, pulmonary venous flow and Tei index and serum markers (PIP and PIIIP) of myocardial fibrosis. A total of 22 hypertensive patients were enrolled into this study. Using 35ug/l of PINP, we divided these patients into 2 groups: group 1 (7 patients with mean PINP 24 ug/l) and group 2 (15 patients with mean PINP 66 ug/l). There were no significant differences between these 2 groups: PIIINP(3.8 ±1.4vs 4.8 ±1.5 ug/l),left ventricular (LV) end-diastolic dimension 40 ±6 vs 43 ±4 mm; LV end-systolic dimension 25 ±4 vs 26 ±3 mm, mitral E/A ratio 0.7 ±0.2 vs 0.8 ±0.2, deceleration time of mitral flow 229 ±59 ms vs 217 ± 49ms, retrograde A wave of pulmonary venous flow 32 ±4 cm/s vs 37 ±7 cm/s, systolic flow of pulmonary venous flow 59 ±5 cm/s vs 67 ±14 cm/s, diastolic flow of pulmonary venous flow 37 ±6 cm/s vs 46 ±10 cm/s, isovolumetric relaxation time 86 ±14 ms vs 84 ±17 ms, Tei index 0.5 ±0.0 vs 0.5 ± 0.1, amplitude of cyclic variation of integrated backscatter 6.7 ±3.1 vs 7.4 ±2.2db. However, there were significant differences between peak filling rate of LV (3.4 ±0.8 vs 2.5 ±0.6 EDV/s; p=0.009) and time to peak filling rate of LV 272 ±130 ms vs 176 ±72 ms; p<0.05].No siginificant association was observed for PIIINP and diastolic dysfunction of LV. In conclusion, ultrasound parameters of diastolic dysfunction of left ventricle are not related to PINP and PIIINP in hypertensive patients. Peak filling rate and time to peak filling rate are associated with PINP rather than PIIINP in such patients

The relation between serum concentrations of procollagen peptides and cardiac changes-evaluation by integrated backscatter and thallium-201 SPECT in hypertensive patients

越來越多的研究顯示心肌纖維化在高血壓心臟變化中扮演了相當重要的角色。利用免疫組織化學呈相法顯示在高血壓心臟病的患者，其心臟間質及冠狀動脈週圍有大量的第一類及第三類纖維膠原沉積。大量的心臟纖維化會導致心室收縮功能異常、冠狀動脈血流異常、及心律不整。在各種人體有關心臟纖維化的病理研究中發現:心肌細胞的超音波反射度與膠原堆積的量有相當程度的關聯性。因此對研究心肌纖維化而言; 加成性超音波逆行散射(週期變化與波幅大小的改變)便成為一種優良的非侵襲性工具。另一方面，膠原纖維原分解的過程中會釋放一些物質如第一類膠原纖維原碳基端分解物(PIP)、第三類膠原纖維原胺基端分解物(PIIIP)至血清中。據研究顯示，這些血清中的膠原纖維分解物與心肌纖維化有關。在肝功能正常的前提下，這些血清中的膠原纖維分解物與組織中膠原纖維製造有量化性的相關。因此我們設計這個研究；將病患分成三組: A 組為正常對照組B 組高血壓病患其血中PIP<127ug/、C 組高血壓病患其血中PIP≧127ug/L。這個研究目的有(1) 比較這三組病患加成性超音波逆行散射(週期變化與波幅大小的改變)與血清中的膠原纖維 分解物(PIP 與PIIIP)之相關 (2) 鉈-201心肌造影與清中的膠原纖維分解物(PIP與PIIIP)之相關。共有21 名病患進入本研 究(每組各7 名)。左心室後壁的加成性超音波逆行散射波幅在C 組與A 及B 組病患有明顯差異(A 組 8.4±1.6 dB; B 組8.8± 2.0dB;C 組6.2 ± 0.8dB)。週期變化則無明顯變化。左心室後壁的加成性超音波逆行散射波幅大小改變之多變項線性回歸與PIP有明顯相關(p<0.05);但與PIIIP 無關。鉈-201 心肌造影與清中的PIIIP 有相關: 有可逆性灌流缺損有者較高之PIIIP(5.6 ±1.2 ug/L vs 4.5 ± 1.0 ug/L; p<0.05)；有固 定性心肌灌流缺損者亦有較高之PIIIP(6.7 ± 1.1 ug/L vs 4.8 ± 0.9 ug/L;p=0.001)。結論: 高血壓病患超音波逆行散 射波幅與膠原纖維分解物PIP 有明顯相關，但與PIIIP 無關。A growing body of evidence indicates that myocardial fibrosis is one of the key pathologic features of myocardial remodeling in hyperensive heart disease. An exaggerated accumulation of collagens type I and type III within the myocardial interstitium and surrounding intramural coronary arteries and arterioles has been evidenced immunohistologically in patients with hypertensive heart disease. Myocardial fibrosis predisposes to ventricular dysfunction, diminished coronary reserve and ventricular arrhythmias, which, in turn, confer increased risk of adverse cardiovascular events to patients with hypertension. To determine the extent of collagen accumulation in tissue may be relevant in assessing the clinical outcome of these patients and in designing strategies to prevent its appearance or even to cause its regression. Studies performed in human with different pathologic conditions involving myocardial fibrosis have shown a promising correlation between echo-reflectivity and histologically assessed collagen content. Therefore, cyclic variation of in returning ultrasound signal intensity (cyclic variation of integrated backscatter) turns to be a non-invasive tool for measurement of myocardial fibrosis. On the other hand, serum procollagen type I carboxy-terminal peptide (PIP) and procollagen type III amino terminal peptide (PIIIP) have been related to myocardial fibrosis. Serum PIP and PIIIP concentration can be considered as a useful marker of myocardial collagen type I and III synthesis in conditions of preserved liver function. Therefore, we classified the hypertensive patients into 3 groups. Group A served as control group; group B included hypertensive patients with PIP<127 ug/L; C included hypertensive patients with PIP ≧ 127 ug/L. This prospective study was designed (1) to analyze the relation between myocardial integrated backscatter and serum markers (PIP and PIIIP) of myocardial fibrosis (2) to analyze the relation between myocardial thallium-201 imaging and serum markers (PIP and PIIIP) of myocardial fibrosis. Group C had the lowest amplitude of CVIBS at the left ventricular posterior wall [LVPW] (group A 8.4±1.6 dB; group B 8.8± 2.0 dB; group C 6.2 ± 0.8dB). There was no significant chages of phase among 3 groups. Multi-variate linear regression showed significant association between CVIBS and PIP rather than PIIIP (p<0.05). There was significant association between thallium-201 imaging between PIIIP rather than PIP. Patients with reversible or fixed perfusion defects had the higher levels of PIIIP than those without (5.6 ± 1.2 ug/L vs 4.5 ± 1.0 ug/L, p<0.05; 6.7 ± 1.1 ug/L vs 4.8 ± 0.9 ug/L; p=0.001). In conclusion: The CVIBS of LVPW is associated with PIP rather than with PIIIP

Conditional Antisense-Knockdown of Zebrafish Cardiac Troponin C as a New Model for Dilated Cardiomyopathy

Background – Mutations of cardiac troponin C (cTnC) can cause dilated cardiomyopathy in humans. We attempted to generate a zebrafish transgenic line that enables us to produce the antinsense RNA strand of cTnC after induction as a new animal model for studying dilated cardiomyopathy. Methods and Results – We constructed plasmids that the reverse tetracycline–controlled transactivator (rtTA) was driven by the cardiac myosin light chain 2 promoter. This heart-specific rtTA bound another bidirectional promoter to express the green fluorescence protein (GFP) reporter gene and to transcribe the antisense RNA of cTnC in the presence of doxycycline (Dox). After microinjection of these constructs into one-cell fertilized eggs, we cultured, screened, and generated a transgenic line of zebrafish (CA17) which enabled us to express GFP and to conditionally produce the antisense RNA of cTnC in heart after induction. When 12-h postfertilization (hpf) embryos of F2 derived from CA17 were given Dox (10 µg/ml), the expression of endogenous cTnC mRNA was not affected until 6 days postfertilization (dpf). The heart rates of the embryos in CA17 were significantly slower than those of embryos in the control T03 transgenic line (only expressing the heart-specific GFP) at 6 dpf (150±10 vs. 194±11 beats/min, p < 0.01) and 12 dpf (128±12 vs. 168±8 beats/min, p < 0.01). Moreover, the various values of cardiac chambers measured in the induced F2 embryos from CA17 were significantly greater than those of T03 embryos; while the ventricular ejection fraction of CA17 was lower than that of the T03 both at 6 dpf (44%±4% vs. 50%±3%, p < 0.01) and at 12 dpf (39%±5% vs. 52%±4%, p <0.01). In addition, asynchronized atrial and ventricular contractions were noted in a few (1.3%) F2 embryos from the induced CA17 transgenic fish. The mortality rate of F2 adult fish of the CA17 group was significantly higher (30% vs. 0%, p < 0.001) than that of F2 adults of the T03 group after Dox induction. Conclusions – Using conditional expression of antisense RNA of zebrafish cTnC, we have created a new animal model with phenotypes simulating dilated cardiomyopathy

Dobutamine Stress Echocardiography Compared with Exercise Thallium-201 Single-Photon Emission Computed Tomography in Detecting Coronary Artery Disease-Effect of Exercise Level on Accuracy

Dobutamine stress echocardiography (DSE) and exercise thallium-201 single - photon emission computed tomography ( SPECT) were compared for the accuracy in detecting coronary artery disease (CAD) in 51 consecutive patients. Twenty-six (group 1) of the 51 patients achieved adequate exercise end points, and 25 (group 2) did not. There were 38 patients with angiographically documented CAD. The overall sensitivity of DSE and thallium-201 SPECT in detecting CAD was 92 and 76% (p = NS), and the specificity was 77 and 77% (p = NS), respectively. The sensitivity of DSE is the same as that of SPECT in group 1 (90 vs. 90%; p = NS) and higher than that of SPECT in group 2 (94 vs. 61%; p < 0.05). In patients with CAD without a history of acute myocardial infarction or pathological Q wave on resting electrocardiogram, the sensitivity of DSE is the same as that of SPECT in group 1 (82 vs. 82%; p = NS) and also higher than that of SPECT in group 2 (90 vs. 40%; p = 0.03). The sensitivity in detecting individual coronary artery lesions with DSE and thallium-201 SPECT was not affected by the exercise level. The agreement between DSE and thallium SPECT in detecting patients with CAD was 88% in group I ( kappa = 0.69; p < 0.001) and 76% in group 2 (kappa = 0.45; p = 0.01). The agreement in detecting vascular territories with ischemia was 68% in group I (kappa = 0 .30; p < 0.01) and 75% in group 2 (kappa = 0.33; p < 0.001). The agreement in detecting vascular territories with a scar was 87% in group I (kappa = 0.55; p < 0.001) and 85% in group 2 (kappa = 0.44; p < 0.001). In conclusion, the sensitivity and specificity of DSE in detecting CAD are similar to that of thallium-201 SPECT with an exercise level ≧85% of the maximal predicted heart rate. However, in patients who cannot exercise adequately, DSE is more accurate than thallium SPECT. The agreement between DSE and thallium SPECT in detecting patients with CAD and identifying ischemia of individual vascular territories is also affected by the exercise level

Assessment of Coronary Artery Disease in Women by Dobutamine Stress Echocardiography: Comparison with Stress Thallium-201 Single-Photon Mission Computed Tomography and Exercise Electrocardiography

BACKGROUND: Dobutamine stress echocardiography (DSE) is sensitive and specific in detecting myocardial ischemia of male patients. However, there have been few reports about the use of DSE for the detection of coronary artery disease( CAD) in women. METHODS: DSE was evaluated in 51 consecutive women who underwent concomitant quantitative coronary angiography. Forty-four of the 51 patients received stress thallium-201 single-photon emission computed tomography ( SPECT), and 30 of the 51 patients had interpretable results( exercise level > or = 85% of age- predicted maximal heart rate) of treadmill exercise. Twenty-nine patients had angiographically documented CAD defined as > or = 50% diameter stenosis. RESULTS: The overall sensitivity of DSE and stress 201Tl SPECT in detecting CAD was 93% and 79% (p = nonsignificant), and the specificity was 82% and 75% (p = nonsignificant), respectively. A combination of both tests increased the sensitivity (96%) at the expense of somedecrease in specificity (60%). The agreement of DSE and 201 Tl SPECT was 68% (30 of 44 ; kappa statistic = 0.35; p < 0.0001). The overall sensitivity, specificity, and accuracy in detecting CAD by treadmill exercise test and DSE were 71% vs 93% (p = nonsignificant), 44% vs 82% (p= 0.036), and 57% vs 88% (p = 0.003). In patients with abnormal results of treadmill exercise testing, the false-positive rate in detecting CAD was 2 (18%) of 11 in patients with abnormal results of DSE and 7 (88%) of 8 in those with normal results of DSE (p = 0.005). In patients with normal results of treadmill exercise testing, the false-negative rate in detecting CAD was 4 (100%) of 4 in patients with abnormal results of DSE and 0 (0%) of 7 in those with normal results of DSE (p = 0.003).CONCLUSION: The diagnostic accuracy of DSE was similar to that of stress 201Tl SPECT in women. DSE was able to stratify female patients with either abnormal or normal results of treadmill exercise testing and to avoid unnecessary cardiac catheterization

Correlations between the Signal Complexity of Cerebral and Cardiac Electrical Activity: A Multiscale Entropy Analysis

The heart begins to beat before the brain is formed. Whether conventional hierarchical central commands sent by the brain to the heart alone explain all the interplay between these two organs should be reconsidered. Here, we demonstrate correlations between the signal complexity of brain and cardiac activity. Eighty-seven geriatric outpatients with healthy hearts and varied cognitive abilities each provided a 24-hour electrocardiography (ECG) and a 19-channel eye-closed routine electroencephalography (EEG). Multiscale entropy (MSE) analysis was applied to three epochs (resting-awake state, photic stimulation of fast frequencies (fast-PS), and photic stimulation of slow frequencies (slow-PS)) of EEG in the 1-58 Hz frequency range, and three RR interval (RRI) time series (awake-state, sleep and that concomitant with the EEG) for each subject. The low-to-high frequency power (LF/HF) ratio of RRI was calculated to represent sympatho-vagal balance. With statistics after Bonferroni corrections, we found that: (a) the summed MSE value on coarse scales of the awake RRI (scales 11-20, RRI-MSE-coarse) were inversely correlated with the summed MSE value on coarse scales of the resting-awake EEG (scales 6-20, EEG-MSE-coarse) at Fp2, C4, T6 and T4; (b) the awake RRI-MSE-coarse was inversely correlated with the fast-PS EEG-MSE-coarse at O1, O2 and C4; (c) the sleep RRI-MSE-coarse was inversely correlated with the slow-PS EEG-MSE-coarse at Fp2; (d) the RRI-MSE-coarse and LF/HF ratio of the awake RRI were correlated positively to each other; (e) the EEG-MSE-coarse at F8 was proportional to the cognitive test score; (f) the results conform to the cholinergic hypothesis which states that cognitive impairment causes reduction in vagal cardiac modulation; (g) fast-PS significantly lowered the EEG-MSE-coarse globally. Whether these heart-brain correlations could be fully explained by the central autonomic network is unknown and needs further exploration

Integrated Backscatter for Quantification and Risk Stratification of Blood Stagnation in Left Atrial Appendages of Patients with Rheumatic Mitral Stenosis

This study was designed to quantify the blood stagnation in left atrial appendages (LAA) of patients with rheumatic mitral stenosis, and to stratify the risk of spontaneous echo contrast (SEC) for thrombus formation. A total of 45 patients were enrolled in this study. Thirty of the 45 patients had rheumatic mitral stenosis. All the above patients were evaluated for LAA contractility by transesophageal echocardiography. Acoustic density of the stagnant blood was assessed using the integrated backscatter (IBS) mode. Multivariate linear regression analysis showed that the significant independent variables determining relative IBS in LAA were the mitral valve area (p = 0.02) and the atrial fibrillation rhythm (p = 0.0003). In patients with mitral stenosis, the IBS in LAA correlated well with the presence of thrombus (p = 0.004) and SEC (p = 0.002). Using the relative IBS in LAA with 6.8 dB as the cutoff value, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value and accuracy of SEC formation in LAA was 83, 86, 95, 60 and 83%, respectively. Using the relative IBS in LAA with 10.0 dB as the cutoff value, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value and accuracy of SEC with thrombus formation in LAA was 80, 80, 67, 89 and 80%, respectively. In conclusion, the blood stasis in LAA can be objectively quantified using IBS. Utilizing different cutoff values, the acoustic densitometry in LAA enables identification of stagnant blood which represents a risk for the development of either SEC only or SEC with thrombus formation. Copyright (C) 2000 S. Karger AG , Basel