BACKGROUND & AIMS: BACKGROUND:In studies showing benefits of cardiac resynchronization therapy (CRT), individual atrioventricular (AV) delays have been optimized using echocardiography. However, the method for AV delay optimization remains controversial. METHODS:In 100 consecutive patients with CRT device implantation, AV delay was optimized using echocardiography. The optimal AV delay was determined by changing the interval in 20-ms increments while measuring displacement in 6 basal left ventricular segments (averaged and reported as left ventricular displacement [D(LV)]) and other echocardiographic measures. RESULTS:A single optimal AV delay existed for each patient, and the associated highest D(LV) corresponded with the maximal velocity-time integral (VTI) in the left ventricular outflow tract (VTI(LVOT)) and the E/e' ratio. Significant increases in D(LV) and the VTI(LVOT) from before to after implantation with standard settings and from standard to optimal AV delay by displacement were found. Diastolic filling time corresponded poorly with D(LV) and the VTI(LVOT). CONCLUSION:Individual optimal AV delay programming provides significant improvement in left ventricular performance and hemodynamics. Displacement analysis and the VTI(LVOT) are interchangeable, whereas diastolic filling time cannot be recommended.

背景与目标：

BACKGROUND & AIMS: :Exocytosis involves membrane fusion between secretory vesicles and the plasma membrane. The Soluble N-ethylmaleimide-sensitive factor attachment proteins (SNAPs) and their receptor proteins (SNAREs) interact to fuse vesicles with the membrane and trigger the release of their sialosecretome out of the tick salivary gland cells. In this study, we examined the functional significance of the Vti family of SNARE proteins of blood-feeding Amblyomma maculatum and Amblyomma americanum. Vti1A and Vti1B have been implicated in multiple functional roles in vesicle transport. QRT-PCR studies demonstrated that the highest transcriptional expression of vti1a and vti1b genes occurs in unfed salivary glands, suggesting that elevated secretory vesicle formation occurs prior to feeding but continues at low rates after blood feeding commences. Vti1A and Vti1B localize to the secretory vesicles in unfed tick salivary glands in immunofluorescence microscopy studies. Knockdown of vti1a and vti1b by RNA interference resulted in a significant decrease in the engorged tick weight compared to the control during prolonged blood-feeding on the host. RNA interference of vti1a or vti1b impaired oviposition and none of the ticks produced eggs masses. Surprisingly, the double knockdown did not produce a strong phenotype and ticks fed normally on the host and produced egg masses, suggesting a compensatory mechanism exists within the secretory system which may have been activated in the double knockdown. These results suggest an important functional role of the Vti family of SNARE proteins in tick blood feeding and ultimately oviposition. Understanding the basic functions of the Vti family of SNARE proteins in salivary glands may lead to better ways to prevent tick attachment and transmission of tick-borne diseases.

背景与目标： : 胞吐作用涉及分泌囊泡和质膜之间的膜融合。可溶性N-乙基马来酰亚胺敏感因子附着蛋白 (SNAPs) 及其受体蛋白 (SNAREs) 相互作用，将囊泡与膜融合，并触发其唾液腺细胞释放出唾液腺细胞。在这项研究中，我们检查了血液喂养的黄斑弱小和美洲弱小的snal蛋白的Vti家族的功能意义。Vti1A和Vti1B在囊泡转运中具有多种功能作用。QRT-PCR研究表明，vti1a和vti1b基因的最高转录表达发生在未进食的唾液腺中，这表明分泌囊泡的形成在进食之前发生，但在开始进食后以较低的速率持续。在免疫荧光显微镜研究中，Vti1A和Vti1B定位于未进食的tick唾液腺的分泌囊泡。与对照组相比，通过RNA干扰敲除vti1a和vti1b导致在宿主上长时间采血期间，饱食的tick虫重量显着降低。vti1a或vti1b的RNA干扰损害了产卵，并且没有一个tick产生卵团。令人惊讶的是，双重敲低并没有产生强烈的表型，而蜱通常在宿主上喂食并产生卵团，这表明分泌系统中存在一种补偿机制，该机制可能已在双重敲低中被激活。这些结果表明，snal蛋白的Vti家族在tick血液喂养和最终产卵中具有重要的功能作用。了解唾液腺中snal蛋白Vti家族的基本功能可能会导致更好的方法来预防tick附着和tick传播疾病的传播。

BACKGROUND & AIMS: BACKGROUND:Ischemia-reperfusion injury results in conduit vessel endothelial dysfunction as assessed by flow-mediated dilatation (FMD). The effect on the potentially more important microvascular circulation has not been well studied. The objective of our study was to assess the effect of ischemia-reperfusion injury on microvascular function including peripheral arterial tonometry (PAT) hyperemic index. METHODS:45 healthy volunteers free of cardiovascular disease were recruited (mean age 35 ± 14 yrs, 29 men). Using ultrasound, the flow-mediated dilation (FMD) and hyperemic velocity (VTI) of the brachial artery were measured following a 5-minute forearm cuff occlusion. Simultaneously, the PAT hyperemic index was measured. Ischemia was then induced by a 15-minute upper arm occlusion and within 15 minutes of recovery the vascular measures were repeated. RESULTS:Ischemia caused a significant reduction in FMD (7.9 ± 4.0 to 4.7 ± 3.5, p = 0.0001). The hyperemic VTI, a measure of microvascular function, was unaffected following ischemia-reperfusion (92 ± 30 vs. 97 ± 37 cm, p = 0.236). Finally, PAT index was also unchanged by the intervention (2.07 ± 0.8 vs. 2.04 ± 0.7, p = 0.742). CONCLUSIONS AND DISCUSSIONS:Ischemia-reperfusion caused conduit and not resistance vessel endothelial dysfunction. The PAT-index was unchanged suggesting that this measure is more closely aligned with resistance than conduit vessel function. This has implications for its use as a measure of vascular function in clinical research.

背景与目标：

BACKGROUND & AIMS: AIMS:It has been shown that optimizing atrioventricular (AV) and interventricular (VV) delay improves cardiac performance in patients with biventricular pacemakers. However, there is no standard method for optimization available yet. The aim of this study was to compare echocardiographic parameters-displacement imaging, A wave duration, and aortic velocity time integral (VTI)-and acoustic cardiography derived electromechanical activation time (EMAT) using different approaches of AV and VV delay optimization. We tested whether the initial optimization of the AV interval followed by VV optimization at that optimal AV interval or initial optimization of the VV interval followed by AV optimization at the determined optimal VV interval was accurate and consistent, and how this compared to testing every conceivable combination of AV and VV intervals available. METHODS AND RESULTS:A group of 20 patients with biventricular pacemakers was included. Displacement imaging, A wave duration, and aortic VTI were determined at different combinations of AV (100, 150, 200, 250 ms) and VV (RV40, 0, LV40 ms) intervals. If AV duration was determined first, displacement imaging identified the best setting in 8/20, aortic VTI in 10/20, A duration in 13/20, and EMAT in 18/20 patients. With VV duration determined first, the best setting was more difficult to identify regardless of the method used. There was a poor agreement in optimal AV and VV delays of the different methods, and there was no single patient in whom all four methods yielded the same delay combination. CONCLUSION:It is advisable to measure a full grid of AV and VV delays to identify optimal settings rather than optimizing one of the two delays first. Different techniques for delay optimization resulted in different optimal delay combinations.

背景与目标：

BACKGROUND & AIMS: Study hypothesis:We sought to investigate the association between echocardiographic optimisation and ventricular activation time in cardiac resynchronisation therapy (CRT) patients, obtained through the use of electrocardiographic mapping (ECM). We hypothesised that echocardiographic optimisation of the pacing delay between the atrial and ventricular leads-atrioventricular delay (AVD)-and the delay between ventricular leads-interventricular pacing interval (VVD)-would correlate with reductions in ventricular activation time. Background:Optimisation of AVD and VVD may improve CRT patient outcome. Optimal delays are currently set based on echocardiographic indices; however, acute studies have found that reductions in bulk ventricular activation time correlate with improvements in acute haemodynamic performance. Materials and methods:Twenty-one patients with established CRT criteria were recruited. After implantation, patients underwent echo-guided optimisation of the AVD and VVD. During this procedure, the participants also underwent noninvasive ECM. ECM maps were constructed for each AVD and VVD. ECM maps were analysed offline. Total ventricular activation time (TVaT) and a ventricular activation time index (VaT10-90) were calculated to identify the optimal AVD and VVD timings that gave the minimal TVaT and VaT10-90 values. We correlated cardiac output with these electrical timings. Results:Echocardiographic programming optimisation was not associated with the greatest reductions in biventricular activation time (VaT10-90 and TVaT). Instead, bulk activation times were reduced by a further 20% when optimised with ECM. A significant inverse correlation was identified between reductions in bulk ventricular activation time and improvements in LVOT VTI (p < 0.001), suggesting that improved ventricular haemodynamics are a sequelae of more rapid ventricular activation. Conclusions:EAM-guided programming optimisation may achieve superior fusion of activation wave fronts leading to improvements in CRT response.

背景与目标：

BACKGROUND & AIMS: BACKGROUND:Point-of-care transthoracic echocardiography (POC-TTE) is essential in shock management, allowing for stroke volume (SV) and cardiac output (CO) estimation using left ventricular outflow tract diameter (LVOTD) and left ventricular velocity time integral (VTI). Since LVOTD is difficult to obtain and error-prone, the body surface area (BSA) or a modified BSA (mBSA) is sometimes used as a surrogate (LVOTDBSA, LVOTDmBSA). Currently, no models of LVOTD based on patient characteristics exist nor have BSA-based alternatives been validated. METHODS:Focused rapid echocardiographic evaluations (FREEs) performed in intensive care unit patients over a 3-year period were reviewed. The age, sex, height, and weight were recorded. Human expert measurement of LVOTD (LVOTDHEM) was performed. An epsilon-support vector regression was used to derive a computer model of the predicted LVOTD (LVOTDCM). Training, testing, and validation were completed. Pearson coefficient and Bland-Altman were used to assess correlation and agreement. RESULTS:Two hundred eighty-seven TTEs with ideal images of the LVOT were identified. LVOTDCM was the best method of SV measurement, with a correlation of 0.87. LVOTDmBSA and LVOTDBSA had correlations of 0.71 and 0.49 respectively. Root mean square error for LVOTDCM, LVOTDmBSA, and LVOTDBSA respectively were 13.3, 37.0, and 26.4. Bland-Altman for LVOTDCM demonstrated a bias of 5.2. LVOTDCM model was used in a separate validation set of 116 ideal images yielding a linear correlation of 0.83 between SVHEM and SVCM. Bland Altman analysis for SVCM had a bias of 2.3 with limits of agreement (LOAs) of - 24 and 29, a percent error (PE) of 34% and a root mean square error (RMSE) of 13.9. CONCLUSIONS:A computer model may allow for SV and CO measurement when the LVOTD cannot be assessed. Further study is needed to assess the accuracy of the model in various patient populations and in comparison to the gold standard pulmonary artery catheter. The LVOTDCM is more accurate with less error compared to BSA-based methods, however there is still a percentage error of 33%. BSA should not be used as a surrogate measure of LVOTD. Once validated and improved this model may improve feasibility and allow hemodynamic monitoring via POC-TTE once it is validated.

背景与目标：

BACKGROUND & AIMS: Fifty patients with rheumatic mitral stenosis aged twelve to thirty-six (twenty +/- six) years were studied by two-dimensional, pulsed and color Doppler echocardiography during, seventy-two hours after, and biweekly for three months after balloon mitral valvuloplasty (BMV). Transesophageal echocardiography (TEE) done immediately after BMV (in the catheterization laboratory) detected a new atrial septal defect (ASD) in 46 (92%) patients. These measured 1 to 2 (mean 1.2 +/- 0.3) mm in diameter. Doppler color flow mapping guided the location of the ASD in most of the cases. A narrow jet of left-to-right shunt could be evaluated by pulsed Doppler studies. Velocity time integral (VTI) of the jet across one cardiac cycle and the diameter of the ASD were used to calculate the left-to-right shunt (shunt = VTI x pi (D/2)2 x heart rate). The estimated shunt was 0.04-0.39 (mean 0.20 +/- 0.10) L/minute. A repeat study at seventy-two hours revealed the defect in 40 (80%) patients. At three months, the defect persisted in only 5 (10%) cases. The mean interval of closure of ASD was 4.6 +/- 2.2 weeks. The authors conclude(1) ASD occurs commonly after BMV, (2) the septal defect and the resultant left-to-right shunt are insignificant, and (3) ASD disappears in the majority of cases by three months after BMV.

背景与目标： 通过二维，脉冲和彩色多普勒超声心动图对50例12至36岁 (二尖瓣狭窄) 的二尖瓣狭窄患者进行了研究。球囊二尖瓣成形术 (BMV)。BMV (在导管实验室) 后立即进行经食管超声心动图 (TEE) 在46 (92%) 例患者中发现了新的房间隔缺损 (ASD)。这些测量的直径为1至2 (平均1.2 +/- 0.3) mm。在大多数情况下，多普勒彩色血流图可指导ASD的位置。可以通过脉冲多普勒研究来评估从左向右分流的窄射流。在一个心动周期内射流的速度时间积分 (VTI) 和ASD的直径用于计算从左向右分流 (分流 = VTI x pi (D/2)2 x心率)。估计分流为0.04-0.39 (平均0.20 +/- 0.10) L/分钟。72小时的重复研究揭示了40 (80%) 名患者的缺陷。在三个月时，缺陷仅在5 (10%) 例中持续存在。ASD的平均闭合间隔为4.6 +/- 2.2周。作者得出的结论是 :( 1) BMV后ASD通常发生; (2) 间隔缺损和由此产生的左右分流无关紧要; (3) 在BMV后三个月内，大多数情况下ASD消失。

BACKGROUND & AIMS: BACKGROUND:The assessment of hemodynamics in patients supported with left ventricular assist devices (LVADs) is often challenging. Physical examination maneuvers correlate poorly with true hemodynamics. We assessed the value of novel transthoracic echocardiography (TTE)-derived variables to reliably predict hemodynamics in patients supported with LVAD. METHODS AND RESULTS:A total of 102 Doppler-TTE images of the LVAD outflow cannula were obtained during simultaneous invasive right heart catheterization (RHC) in 30 patients supported with continuous-flow LVADs (22 HMII, 8 HVAD) either during routine RHC or during invasive ramp testing. Properties of the Doppler signal though the outflow cannula were measured at each ramp stage (RS), including the systolic slope (SS), diastolic slope (DS), and velocity time integral (VTI). Hemodynamic variables were concurrently recorded, including Doppler opening pressure (MAP), heart rate (HR), right atrial pressure, pulmonary artery pressure, pulmonary capillary wedge pressure (PCWP), Fick cardiac output (CO) and systemic vascular resistance (SVR). Univariate and multivariate regression analyses were used to explore the dependence of PCWP, CO, and SVR on DS, SS, VTI, MAP, HR, and RS. Multivariate linear regression analysis revealed significant contributions of DS on PCWP (PCWPpred = 0.164DS + 4.959; R = 0.68). Receiver operating characteristic (ROC) curve analysis revealed that PCWPpred could predict an elevated PCWP ≥18 mm Hg with a sensitivity (Sn) of 94% and specificity (Sp) of 85% (area under the ROC curve 0.88). CO could be predicted by RS, VTI, and HR (COpred = 0.017VTI + 0.016HR + 0.12RS + 2.042; R = 0.61). COpred could predict CO ≤4.5 L/min with Sn 73% and Sp 79% (AUC 0.81). SVR could be predicted by MAP, VTI, and HR (SVRpred = 15.44MAP - 5.453VTI - 6.349HR + 856.15; R = 0.84) with Sn 84% and Sp 79% (AUC 0.91) to predict SVR ≥1200 dyn-s/cm5. CONCLUSIONS:Doppler-TTE variables derived from the LVAD outflow cannula can reliably predict PCWP, CO, and SVR in patients supported with LVADs and may mitigate the need for invasive testing.

背景与目标：

BACKGROUND & AIMS: :The goal of our study was to investigate the value of color-coded Virtual Touch tissue imaging (VTI) using acoustic radiation force impulse (ARFI) technology in the characterization of breast lesions and to compare it with conventional ultrasound (US). Conventional US and color-coded VTI were performed in 196 solid breast lesions in 196 consecutive women (age range 17-91 y; mean 48.17 ± 14.46 y). A four-point scale VTI score was assigned for each lesion according to the color pattern both in the lesion and in the surrounding breast tissue. The mean VTI score was significantly higher for malignant lesions (3.80 ± 0.66, range 1-4) than for benign ones (2.02 ± 1.20, range 1-4) (p < 0.001), and the optimal cut-off value was between score 3 and score 4. The area under the receiver operating characteristic (ROC) curve for combined conventional US and VTI (0.945) was significantly higher than that for conventional US (0.902) and for VTI (0.871) (p = 0.0021 and p < 0.001, respectively). It was concluded that color-coded VTI with the proposed four-point scale score system combined with conventional US might have the potential to aid in the characterization of benign and malignant breast lesions.

背景与目标： : 我们研究的目的是研究使用声辐射力冲动 (ARFI) 技术的彩色编码虚拟触摸组织成像 (VTI) 在乳腺病变特征中的价值，并将其与常规超声 (US) 进行比较。在连续196名女性 (年龄范围17-91岁; 平均48.17 ± 14.46岁) 的196个乳腺实体病变中进行了常规US和颜色编码的VTI。根据病变和周围乳腺组织中的颜色模式，为每个病变分配四点VTI评分。恶性病变的平均VTI评分 (3.80 ± 0.66，范围1-4) 明显高于良性病变 (2.02 ± 1.20，范围1-4) (p <0.001)，最佳临界值介于3分和4分之间。组合常规US和VTI (0.945) 的接收器工作特性 (ROC) 曲线下的面积显著高于常规US (0.902) 和VTI (0.871) (分别为p = 0.0021和p <0.001)。结论是，将颜色编码的VTI与拟议的四点量表评分系统结合使用常规US可能具有帮助表征良性和恶性乳腺病变的潜力。

BACKGROUND & AIMS: INTRODUCTION/OBJECTIVE:This study consist of an experiment comparing acoustic characteristics of vowel production among females. The aim of this investigation was to explore the stability among vowels with quantification of acoustic changes in the voice related to speech production associated with an ample variety of vowel sounds. An additional goal was to establish a systematic control of variables and standardization of the data collection procedures. METHODS:All data were collected in a quiet environment using the Computerized Speech Lab (CSL; Kay Elemetrics, Montvale, NJ), a computer-based system designed to measure characteristics of voice. Jitter and shimmer, measures of perturbation that reflect characteristics of voice, were applied. Two additional acoustic measures were examined: (1) noise-to-harmonic ratio (NHR), a general evaluation of presence of noise in the voice signal; and (2) voice turbulence index (VTI), related to turbulence caused by abnormal adduction of vocal folds. A systematic methodology of data collection was organized, in an effort to establish a research protocol based on relevant literature, involving (1) keeping constant fundamental frequency (F0) and intensity, (2) positioning of participants and recording equipment, and (3) environmental noise. RESULTS AND CONCLUSION:When measured acoustic parameters of vowels were compared, results revealed that the vowel sounds had a significant effect on shimmer and VTI. Furthermore, speech sounds classified as back vowels exhibited less perturbation and noise in the acoustic signal: the high-back vowels [u] and []; and the mid-back vowels [o] and [], demonstrated most of the statistically significant reduced values of shimmer and VTI among the 12 vowels compared. Further comparisons among front and back vowels grouped in clusters associated to more and less variability led to statistically significant differences in shimmer, NHR, and VTI. Overall, speech sounds classified as back vowels exhibited less variability and noise. Based on the results of this study, back vowels of the English language should be used in voice acoustic tasks in females, given the higher stability of their acoustic signal, as compared with other vowels tested.

背景与目标：

BACKGROUND & AIMS: BACKGROUND:To report first clinical experience on three cases of congenital complete heart block and the use of a pacemaker system with a maximum lower rate interval of 95 beats per minute. METHODS:We retrospectively analyzed three patients treated with a pacemaker system with a maximum lower rate interval of 95 beats per minute suffering from congenital complete heart block. We report a follow up period of 2.9 years, focusing on the patients' growth, development, and adverse events, as well as pacemaker function. RESULTS:In all three patients pacemaker function was impeccable, including minute ventilation sensor rate adaption. All patients showed limited growths as expected, adequate development, good feeding tolerability and circadiane heart rate adaption. One patient experienced skin traction and revision. All patients showed high aortic velocity time integral values after birth. CONCLUSION:The use of a pacemaker system with a maximum lower rate interval of 95 beats per minute in infants suffering from congenital complete heart block and showing high aortic VTI values seems to be feasible and to result in limited growths but adequate development.

背景与目标：

BACKGROUND & AIMS: BACKGROUND:It remains unclear which echocardiographic measure is most suitable for serial measurement in real-world aortic stenosis (AS) follow-up. We determine whether the dimensionless index (DI) between aortic valve and left ventricular outflow tract velocities is measured more consistently using velocity-time-integral (VTI) or peak velocities (V(peak)) in real life. METHODS:Serial echocardiograms acquired within 6 months in subjects with AS were analysed with blinding, to compare the variability over time of DI calculated using V(peak), with that of DI calculated using VTI. RESULTS:Paired echocardiograms, acquired on average 72 days apart, were analysed from 70 patients with a range of severities of AS (59% severe). DI, calculated using either V(peak) or VTI, did not significantly change over this short time. Coefficient of variation was significantly better when DI was calculated using V(peak) than VTI (12.6 versus 25.4%, p<0.0001). The variabilities of mean and peak trans-aortic valve 4v(2) and left ventricular outflow tract VTI were no better: 26.9%, 19.1% and 22.1% respectively. CONCLUSIONS:Serially-followed variables require minimal noise to maximise detection of genuine change. For AS surveillance, calculating DI--or effective orifice area--from the ratio of V(peak) rather than VTIs would reduce 95% confidence intervals from ± 51% to a still-disappointing ± 25%. Guidelines recommend noisy surveillance measures, causing conscientious echocardiographers to 'peek' at previous values, and impairing clinicians' faith in echocardiographically-observed changes when making clinical decisions. For us in echocardiography to improve our ability to contribute to AS follow-up requires us to first acknowledge and discuss this honestly.

背景与目标：

BACKGROUND & AIMS: INTRODUCTION:Recent studies suggest that women with end-stage renal disease (ESRD) may have higher rates of mortality than men, but it is unknown whether sex differences in vascular function explain this disparity. The cardiac, endothelial function, and arterial stiffness in ESRD (CERES) study is an ongoing, prospective observational study designed to investigate vascular function, myocardial injury, and cardiovascular outcomes in ESRD. METHODS:Among 200 CERES participants (34% women), we evaluated arterial wave reflections as augmentation index normalized to a heart rate of 75 (AIx75), arterial stiffness as pulse wave velocity, and macro- and microvascular endothelial dysfunction as flow-mediated dilation and velocity time integral (VTI). Over a median of 14 months, participants were followed for the composite outcome of cardiovascular hospitalization or all-cause death. FINDINGS:Women had higher arterial wave reflection (Mean, SD AIx75 30% ± 9% for women vs. 21% ± 10% for men; P < 0.001) and worse microvascular function (VTI 55 ± 30 cm for women vs. 70 ± 27 cm for men; P = 0.007). After multivariable adjustment, female sex remained associated with a 0.5-SD higher AIx75 (95% CI [0.01, 0.9]) and 0.3-SD lower VTI (95%CI [0.1, 0.7]). Women experienced higher adjusted rates of the composite outcome (HR 2.5; 95%CI [1.1, 5.6]; P = 0.03), and further adjustment for arterial wave reflection attenuated this risk. DISCUSSION:Vascular dysfunction may partly explain the association of female sex with higher cardiovascular risk and mortality in patients with ESRD. Further studies are needed to explore whether sex differences in vascular function predict long-term outcomes, and whether hormonal or inflammatory factors explain these associations.

背景与目标：

BACKGROUND & AIMS: BACKGROUND:Acute changes of the AV-delay in CRT patients have a significant impact on hemodynamics. However, the chronic functional effects of AV-delay optimization have not been systematically examined despite of their potential role for chronic functional improvement. METHODS:Therefore, in this study we investigated whether optimization of AV-delay in CRT patients as assessed by echocardiographic measurement of the velocity time integral of the left ventricular outflow tract (LVOT-VTI) chronically changes (1) echocardiographic parameters of systolic and diastolic left ventricular function, (2) walking distance in the 6-min walk test, (3) levels of NT-proBNP and (4) quality of life as assessed by a standard questionnaire. 33 patients underwent optimization of AV-delay 31+/-8 weeks after initiation of CRT. Follow up (FU) was conducted 43+/-5 days later. RESULTS:E/Ea, the ratio of peak E-wave of mitral inflow and of TDI of the mitral annulus, significantly decreased immediately post-optimization (11+/-1 vs. 14+/-1 at baseline, p<0.05) and further decreased at FU (8+/-1, p<0.05 vs. immediately post-optimization) indicating improvement of diastolic function, while traditional parameters of diastolic function derived from pulse wave Doppler remained unchanged. There was a slight increase of LV-ejection fraction as assessed by echocardiography acutely after optimization (baseline: 25+/-2%, optimized: 28+/-1%, p<0.05), while LV-ejection fraction at FU did not differ from baseline. 6-min walk test improved from 449+/-17 m (baseline) to 475+/-17 m at FU (p<0.05). During this period NT-proBNP significantly decreased from 3193+/-765 ng/l to 2593+/-675 ng/l (p<0.05). Quality of life was unchanged at FU. CONCLUSION:This study demonstrates for the first time chronic functional improvement due to AV-delay optimization in patients with CRT.

背景与目标：

BACKGROUND & AIMS: BACKGROUND:We report a novel method to estimate regional blood flow in the atelectatic lung using transesophageal echocardiography in an experimental dog model. To verify the efficacy of the method, we investigated the ability of this experimental model to detect changes in regional pulmonary blood flow. METHODS:Fourteen anesthetized and ventilated mongrel dogs were randomized into an isoproterenol group (n = 7) or a dopamine group (n = 7). To produce an atelectatic lesion, 60 mL/kg of saline was infused into the left pleural space. The velocity time integral (VTI) derived from pulse Doppler was evaluated as an index of blood flow in the atelectatic lesion. To investigate the response of the method to changes in blood flow, the VTI and the shunt fraction (Qs/Qt) were measured during systemic administration of isoproterenol 0.05 microg x kg(-1) x min(-1) (as a pulmonary vasodilator) and dopamine 10 microg x kg(-1) x min(-1) (as a pulmonary vasoconstrictor). RESULTS:Both VTI and Qs/Qt were increased significantly by isoproterenol administration. There was a significant correlation between the percentage changes of VTI and Qs/Qt with isoproterenol administration (r2 = 0.50, P < 0.001). Both VTI and Qs/Qt were unchanged during administration of dopamine. CONCLUSIONS:Transesophageal echocardiography may be useful in detecting changes in regional pulmonary blood flow in an atelectatic lesion.

背景与目标：