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Transthoracic echocardiography is widely used in intensive care unit (ICU) to manage patients with acute circulatory failure. Recently, automated ultrasound (US) measurement applications have been developed but their clinical performance has not been evaluated yet. The aim of this study was to assess the agreement between automated and manual measurements of the velocity-time integral in the left ventricular outflow tract (VTI-LVOT) using the auto-VTI® tool. This prospective, single-center, interventional study included ICU patients with acute circulatory failure. The examination involved two successive manual measurements of VTI-LVOT (mean of 3 consecutive heartbeats in regular sinus rhythm, and 5 heartbeats in irregular rhythm), followed by a measurement using auto-VTI® software. In patients receiving a fluid challenge, trending ability in detecting fluid responsiveness was also evaluated. Seventy patients were included between January 19, 2020, and September 24, 2020, at the Nîmes University Hospital. The feasibility of the auto-VTI® was 94%. The mean difference between the two methods was 11% with limits of agreement from - 19% to 42%. The proportion of agreement at the 15% difference threshold was 68% [58%; 80%]. The precision and least significant change measured for the manual measurement of VTI were 7.4 and 10.5%, respectively, and by inference for the automated method 28% and 40%. The new auto-VTI® tool, despite interesting feasibility, demonstrated an insufficient agreement with a systematic bias and an insufficient precision limiting its implementation in critically ill patients.Clinical trial registration: ClinicalTrials.gov identifier: NCT04360304.

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Background: Patients undergoing surgical resection of brain tumors frequently exhibit a spectrum of hemodynamic fluctuations necessitating careful fluid management. This study aimed to evaluate the feasibility of dynamic predictors of fluid responsiveness, such as delta down (DD), aortic velocity time integral variability (VTIAoV), and superior vena cava collapsibility index (SVCCI), in patients undergoing neurosurgery for brain tumors. Methods: In this prospective study, 30 patients scheduled to undergo elective neurosurgery for brain tumor resection were enrolled. Baseline measurements of vitals, anesthetic parameters, and study variables were recorded post-induction. Subsequently, patients received a fluid bolus of 10 mL/kg of colloid over 20 min, and measurements were repeated post-loading. Data were presented as mean ± standard deviation. The normally distributed continuous variables were compared using Student's t-test, with P < 0.05 considered statistically significant. The predictive capability of variables for fluid responsiveness was assessed using Pearson's coefficient analysis (r). Results: Of the 30 patients, 22 were identified as volume responders (R), while eight were non-responders (NR). DD >5 mmHg effectively distinguished between R and NR (P < 0.001), with a good predictive ability (r = 0.759). SVCCI >38% differentiated R from NR (P < 0.001), with excellent predictability (r = 0.994). Similarly, VTIAoV >20% was also a good predictor (P < 0.05; r = 0.746). Conclusion: Our study revealed that most patients undergoing surgical resection of brain tumors exhibited fluid responsiveness. Among the variables assessed, SVCCI >38% emerged as an excellent predictor, followed by VTIAoV >20% and DD >5 mm Hg, for evaluating fluid status in this population.

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OBJECTIVE: The echocardiographic assessment of the systemic right ventricle (sRV) performance during stress testing is limited and evaluation is not routinely performed. The aim of the study is to investigate sRV myocardial performance at rest and with exercise in patients with complete transposition of the great arteries (dTGA) who have undergone atrial switch operation. METHODS: In a single-center cross-sectional study, 41 patients with dTGA following the atrial switch operation and gender-matched 20 healthy volunteers underwent exercise echocardiography on a bicycle ergometer in the semi-supine position to assess sRV systolic function indices: tricuspid annular plane systolic excursion (TAPSE), right ventricular area change (FAC), global longitudinal strain (GLS) and systemic velocity time integral (VTI). RESULTS: Patients with sRV were characterized by lower systolic function assessed by TAPSE, s', FAC, GLS both at baseline and at peak exercise, compared with the control group. sRV GLS decreased during exercise in patients with sRV (-6 + 2.84) compared to increased in patients with systemic left ventricle (0.47 + 2.74), p < 0.001. There was no increase in VTI during exercise in patients with sRV, compared to controls (Δ VTI -0.01 ± 2.96 cm vs. Δ VTI 4.50 ± 3.13 cm, p < 0.001). There was a trend towards higher chronotropic incompetence in patients with sRV vs. control (61% vs. 45%, p = 0.28). CONCLUSION: Our results confirmed that patients with dTGA have reduced ability to increase myocardial contractility and stroke volume during exercise. Chronotropic incompetence was prevalent in dTGA patients.

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PURPOSE: Suboptimal response to cardiac resynchronization therapy (CRT) may be improved by optimization of device parameters using echocardiography. For this purpose, the aortic velocity-time integral (aVTI) has been used as a target metric to define optimal velocity timings for each ventricle. dP/dt is a parameter used for the assessment of myocardial contractility. In this study, we aimed to evaluate the effectiveness of Doppler-derived dP/dt in optimization by assessing the possible correlation between aVTI and dP/dt. METHODS: Patients with CRT admitted for routine follow-up were included in the study. Aortic VTI and dP/dt measurements were recorded in four different standard pacing configurations during reprogramming. RESULTS: A total of 45 patients were included in the final analysis. No correlation was found between the aVTI and the delta dP/dt value in the two configurations where the change in dP/dt was maximum (p = 0.894). In the two configurations where the change in aVTI was maximum, there was also no correlation between the delta dP/dt and the delta aVTI (p = 0.715). When patients were dichotomized according to the median value of dP/dt, there were no differences in aVTI, NYHA classes, LVEF, and mitral regurgitation (MR) severity (p = 0.4; p = 0.5; p = 0.7; p = 0.3; respectively). The change in both dP/dt and aVTI was statistically significant when switching from RV-only to QRS width-targeted configuration (p = 0.001; p = 0.041; respectively). CONCLUSION: In conclusion, aVTI recorded at different pacing configurations did not correlate with dP/dt during interventricular optimization. However, both parameters consistently showed a positive effect of biventricular pacing on contractile synchronization and stroke volume.

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Fluid management in obstetrical care is crucial because of the complex physiological conditions of pregnancy, which complicate clinical manifestations and fluid balance management. This expert review examined the use of point-of-care ultrasound to evaluate and monitor the response to fluid therapy in pregnant patients. Pregnancy induces substantial physiological changes, including increased cardiac output and glomerular filtration rate, decreased systemic vascular resistance, and decreased plasma oncotic pressure. Conditions, such as preeclampsia, further complicate fluid management because of decreased intravascular volume and increased capillary permeability. Traditional methods for assessing fluid volume status, such as physical examination and invasive monitoring, are often unreliable or inappropriate. Point-of-care ultrasound provides a noninvasive, rapid, and reliable means to assess fluid responsiveness, which is essential for managing fluid therapy in pregnant patients. This review details the various point-of-care ultrasound modalities used to measure dynamic changes in fluid status, focusing on the evaluation of the inferior vena cava, lung ultrasound, and left ventricular outflow tract. Inferior vena cava ultrasound in spontaneously breathing patients determines diameter variability, predicts fluid responsiveness, and is feasible even late in pregnancy. Lung ultrasound is crucial for detecting early signs of pulmonary edema before clinical symptoms arise and is more accurate than traditional radiography. The left ventricular outflow tract velocity time integral assesses stroke volume response to fluid challenges, providing a quantifiable measure of cardiac function, which is particularly beneficial in critical care settings where rapid and accurate fluid management is essential. This expert review synthesizes current evidence and practice guidelines, suggesting the integration of point-of-care ultrasound as a fundamental aspect of fluid management in obstetrics. It calls for ongoing research to enhance techniques and validate their use in broader clinical settings, aiming to improve outcomes for pregnant patients and their babies by preventing complications associated with both under- and overresuscitation.

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AIMS: Right ventricular (RV) failure is one of the leading causes of death in patients with pulmonary hypertension (PH). Conventional echocardiographic parameters are not included in risk stratification and follow-up for prognostic assessment due to PH's diverse nature and the RV's complex geometry. RV outflow tract velocity time integral (RVOT VTI) is a simple, non-invasive estimate of pulmonary flow and an echocardiographic surrogate of RV stroke volume. In this study, we aimed to define the prognostic value of RVOT VTI in PH patients. METHODS: Sixty-three subjects with idiopathic PAH (IPAH) (n = 23), connective tissue disease-associated PAH (CTD-associated PAH) (n = 19) and chronic thromboembolic pulmonary hypertension (CTEPH) (n = 21) were retrospectively included. A comprehensive two-dimensional echocardiographic evaluation, including RVOT-VTI measurement, was performed during the follow-up and the New York Heart Association functional class (NYHA FC), 6 min walk distance (6MWD) and brain natriuretic peptide (BNP) levels were recorded. RESULTS: The median age of the whole cohort was 63 years (52-68), and 47 (74.6%) of the patients were women. The median follow-up period was 20 months (11-33), and 20 (31.7%) patients died in this period. BNP values were higher [317 (210-641) vs 161 (47-466), P = 0.02], and 6MWD values were lower [197.5 ± 89.5 vs 339 ± 146.3, P < 0.0001] in the non-survivor group, and the non-survivor group had a worse NYHA-FC (P = 0.02). Among echocardiographic data, tricuspid annular plane systolic excursion (TAPSE) (15.4 ± 4.8 vs 18.6 ± 4.2, P = 0.01) and RVOT VTI (11.9 ± 4.1 vs 17.2 ± 4.3, P < 0.0001) values were lower whereas right atrial area (RAA) (26.9 ± 10.1 vs 22.2 ± 7.1, P = 0.04) values were higher in the non-survivor group. The area under curve of the RVOT VTI for predicting mortality was 0.82 [95% confidence interval (CI) 0.715-0.940, P < 0.0001], and the best cut-off value was 14.7 cm with a sensitivity of 80% and specificity of 77%. Survival was significantly lower in subjects with RVOT VTI ≤ 14.7 cm (log-rank P < 0.0001). Survival rates for patients with RVOT VTI ≤ 14.7 cm were 70% at 1 year, 50% at 2 years, %29 at 3 years and 21% at 5 years. The univariate determinants of all-cause mortality were BNP [hazard ratio (HR) 1.001 (1.001-1.002), P = 0.001], 6MWD [HR 0.994 (0.990-0.999), P = 0.012] and NYHA-FC III-IV [HR 3.335 (1.103-10.083), P = 0.03], TAPSE [HR 0.838 (0.775-0.929), P = 0.001], RAA [HR 1.072 (1.013-1.135), P = 0.016] and RVOT VTI [HR 0.819 (0.740-0.906), P < 0.0001]. RVOT VTI was found to be the only independent determinant of mortality [HR 0.857 (0.766-0.960), P = 0.008]. CONCLUSIONS: The decreased RVOT VTI predicts mortality in patients with PH and each 1 mm decrease in RVOT VTI increases the risk of mortality by 14.3%. This parameter might serve as an additional parameter in the follow-up of these patients especially when 6MWD and NYHA-FC could not be determined.

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Background: Residual mitral regurgitation (MR) is frequent after transcatheter edge-to-edge repair (TEER). There is controversy regarding the clinical impact of residual MR and its quantitative assessment by transthoracic echocardiography (TTE), which is often challenging with multiple eccentric jets and artifact from the clip. The utility of the velocity time integral (VTI) ratio between the mitral valve (MV) and left ventricular outflow tract (LVOT), (VTIMV/LVOT), a simple Doppler measurement that increases with MR, has not been assessed post TEER. Methods: Baseline characteristics, clinical outcomes, and TTE data from patients who underwent TEER between 2014 and 2021 across three academic centers were retrospectively analyzed. Post-procedure TTEs were evaluated for VTIMV/LVOT in the first three months after TEER. One-year outcomes including all-cause and cardiac mortality, major adverse cardiac events, and MV reintervention were compared between patients with high VTIMV/LVOT (≥2.5) and low (<2.5). Results: In total, 372 patients were included (mean age 78.7 ± 8.8 years, 68 % male, mean pre-TEER ejection fraction of 50.5 ± 14.7 %). Follow up TTEs were performed at a median of 37.5 (IQR 30-48) days post-procedure. Patients with high VTIMV/LVOT had significantly higher all-cause mortality (HR 2.10, p = 0.003), cardiac mortality (HR 3.03, p = 0.004) and heart failure admissions (HR 2.28, p < 0.001) at one-year post-procedure. There was no association between raised VTIMV/LVOT and subsequent MV reintervention. Conclusion: High VTIMV/LVOT has clinically significant prognostic value at one year post TEER. This tool could be used to select patients for consideration of repeat intervention.

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PURPOSE: The echocardiography parameters may predict the maintenance of sinus rhythm after cardioversion of a supraventricular arrhythmia (SVA). MATERIALS AND METHODS: Patients in septic shock with onset of an SVA, normal to moderately reduced LV systolic function (EF_LV˃̳35%) and on a continuous noradrenaline of <1.0 µg/kg.min were included. Echocardiography was performed at the arrhythmia onset, 1 h and 4 h post cardioversion on an infusion of propafenone or amiodarone. RESULTS: Cardioversion was achieved in 96% of the 209 patients within a median time of 6(1.8-15.6)h, 134(64.1%) patients experienced at least one SVA recurrence after cardioversion. At 4 h the left atrial emptying fraction (LA_EF, cut-off 38.4%, AUC 0.69,p˂0.001), and transmitral A wave velocity-time-integral (Avti, cut-off 6.8 cm, AUC 0.65,p = 0.001) showed as limited predictors of a single arrhythmia recurrence. The LA_EF 44(36,49)%, (p = 0.005) and the Avti 8.65(7.13,9.50)cm, (p < 0.001) were associated with sustained sinus rhythm and decreased proportionally to increasing numbers of arrhythmia recurrences (p < 0.001 and p = 0.007, respectively). The enlarged left atrial end-systolic diameter at the arrhythmia onset (p = 0.04) and elevated systolic pulmonary artery pressure at 4 h (p = 0.007) were weak predictors of multiple(˃3) recurrences. CONCLUSION: The LA_EF and Avti are related to arrhythmia recurrences post-cardioversion suggesting potential guidance to the choice between rhythm and rate control strategies. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03029169, registered on 24th of January 2017.

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BACKGROUND: There is a close linkage between anxiety disorders (ADs), and development of cardiovascular disease (CVD) and atrial fibrillation (AF). We aimed to investigate left atrial function index (LAFI) and its components, LA mechanical functions and atrial conduction times in AD patients and age- and gender-matched control group patients for the first time in the literature. METHODS: A total of 48 AD patients and 33 healthy subjects were enrolled to the study prospectively. Echocardiographic parameters including two-dimensional conventional echocardiography, diastolic functions, LA mechanical functions, LAFI, atrial conduction times and atrial electromechanical delay (AEMD) were calculated. RESULTS: The velocity-time integral of the LV outflow tract (LVOT-VTI), LAFI and LA conduit volume were significantly lower in AD patients. Atrial electromechanical coupling as established from lateral mitral annulus (PA lateral) was significantly higher in AD group than control group. Inter-AEMD and left intra-AEMD were also higher in AD group compared to control group. Age, gender, body surface area (BSA), conduit volume, LVOT-VTI and LAFI were significant factors associated with AD in univariate analysis. However, only BSA and LVOT-VTI (Odds ratio [OR]: 0.79, 95 CI%: 0.66-0.95, p = 0.013) were independently associated with AD in multivariate analysis. Age, gender, conduit volume and LAFI (OR: 0.25, 95 CI%: 0.03-2.12, p = 0.204) were not found to be independent associates of AD. CONCLUSION: LAFI is impaired in patients suffering from AD compared to their age- and gender-matched counterparts but this impairment originates from lower levels of LVOT-VTI calculations in AD patients. Thus, LVOT-VTI, but not LAFI, is independently associated with AD.

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OBJECTIVES: The aim of the study was to compare left ventricle stroke volume in healthy, eutrophic fetuses in the 2nd and 3rd trimesters evaluated using the velocity time integral and aortic annulus area with left ventricular stroke volume measured using Simpson's single-plane rule and to determine the discrepancy equation. METHODS: The study included 354 fetuses. In each fetus, during the same examination, simultaneous assessment of stroke volume was performed by pulsed-wave Doppler using the product of the velocity time integral and aortic annulus area and by the fetalHQ® software using Simpson's single-plane rule. The Mann-Whitney U test was used to compare the "product-derived" stroke volume and stroke volume using fetalHQ® software values in the 2nd and 3rd trimesters separately. The agreement between the two methods were verified using Bland-Altman analysis. A linear regression model was used to obtain the discrepancy equation. RESULTS: In the 2nd trimester, the mean percentage difference between both the techniques showed that the stroke volume values determined using pulsed-wave Doppler were, on average, 88% higher than the stroke volume values determined using fetalHQ®. The upper limit of agreement between the compared techniques was approximately 146% and the lower limit of agreement was equal to 29.6%. In the 3rd trimester, the results indicated that the stroke volume values determined using pulsed-wave Doppler were, on average, 76% higher than the stroke volume values determined using fetalHQ®. The upper limit of agreement between the compared techniques was approximately 129% and the lower limit of agreement was 23%. Based on the results of the linear regression models, discrepancy formulas of the stroke volume values were obtained. The equations to calculate the predicted mean and standard deviations were used to compute the reference intervals for the mean, 5th and 95th centiles. CONCLUSION: The calculation of left ventricular stroke volume using pulsed Doppler has higher result in relation to stroke volume determined using Simpson's rule significantly. The aortic annulus area showed a higher correlation regarding stroke volume than the velocity time integral in both the 2nd and 3rd trimesters. Stroke volume increased with the increase in aortic annulus area, whereas the velocity time integral remained relatively constant. The retrospective analysis of the collected material enabled the determination of the discrepancy equation.

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BACKGROUND: Using peripheral arteries to infer central hemodynamics is common among hemodynamic monitors. Doppler ultrasound of the common carotid artery has been used in this manner with conflicting results. We investigated the relationship between changing common carotid artery Doppler measures and stroke volume (SV), hypothesizing that more consecutively-averaged cardiac cycles would improve SV-carotid Doppler correlation. METHODS: Twenty-seven healthy volunteers were recruited and studied in a physiology laboratory. Carotid artery Doppler pulse was measured with a wearable, wireless ultrasound during central hypovolemia and resuscitation induced by a stepped lower body negative pressure protocol. The change in maximum velocity time integral (VTI) and corrected flow time of the carotid artery (ccFT) were compared with changing SV using repeated measures correlation. RESULTS: In total, 73,431 cardiac cycles were compared across 27 subjects. There was a strong linear correlation between changing SV and carotid Doppler measures during simulated hemorrhage (repeated-measures linear correlation [Rrm ]=0.91 for VTI; 0.88 for ccFT). This relationship improved with larger numbers of consecutively-averaged cardiac cycles. For ccFT, beyond four consecutively-averaged cardiac cycles the correlation coefficient remained strong (i.e., Rrm of at least 0.80). For VTI, the correlation coefficient with SV was strong for any number of averaged cardiac cycles. For both ccFT and VTI, Rrm remained stable around 25 consecutively-averaged cardiac cycles. CONCLUSIONS: There was a strong linear correlation between changing SV and carotid Doppler measures during central blood volume loss. The strength of this relationship was dependent upon the number of consecutively-averaged cardiac cycles.

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The left ventricular outflow tract velocity time integral (LVOT VTI) is commonly used in the intensive care unit as a measure of stroke volume (SV) and how the SV changes in response to an intervention; therefore, the LVOT VTI is used to guide intravenous fluid management. Various peripheral Doppler surrogates are proposed to infer the LVOT VTI (e.g., measures from the common carotid artery). A recently-described, novel method of insonation has an excellent ability to detect change in the LVOT VTI. This approach raises important facets of Doppler flow and insonation error, as well as the general principles at play when using a peripheral artery to infer changes from the left ventricle. Relating the VTI of a peripheral artery to the LVOT VTI was recently described mathematically and may help clinicians think about the Doppler relationship between central and peripheral flow.

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BACKGROUND: Present evidence suggests that the Doppler ultrasonographic indices, such as carotid artery blood flow (CABF) and velocity time integral (VTI), had the ability to predict fluid responsiveness in non-obstetric patients. The purpose of this study was to assess their capacity to predict fluid responsiveness in spontaneous breathing parturients undergoing caesarean section and to determine the effect of detecting and management of hypovolemia (fluid responsiveness) on the incidence of hypotension after anaesthesia. METHODS: A total of 72 full term singleton parturients undergoing elective caesarean section were enrolled in this study. CABF, VTI, and hemodynamic parameters were recorded before and after fluid challenge and assessed by carotid artery ultrasonography. Fluid responsiveness was defined as an increase in stroke volume index (SVI) of 15% or more after the fluid challenge. RESULTS: Thirty-one (43%) patients were fluid responders. The area under the ROC curve to predict fluid responsiveness for CABF and VTI were 0.803 (95% CI, 0.701-0.905) and 0.821 (95% CI, 0.720-0.922). The optimal cut-off values of CABF and VTI for fluid responsiveness was 175.9 ml/min (sensitivity of 74.0%; specificity of 78.0%) and 8.7 cm/s (sensitivity of 67.0%; specificity of 90.0%). The grey zone for CABF and VTI were 114.2-175.9 ml/min and 6.8-8.7 cm/s. The incidence of hypotension after the combined spinal-epidural anaesthesia (CSEA) was significantly higher in the Responders group 25.8% (8/31) than in the Non-Responders group 17.1(7/41) (P < 0.001). The total incidence of hypotension after CSEA of the two groups was 20.8% (15/72). CONCLUSIONS: Ultrasound evaluation of CABF and VTI seem to be the feasible parameters to predict fluid responsiveness in parturients undergoing elective caesarean section and detecting and management of hypovolemia (fluid responsiveness) could significantly decrease incidence of hypotension after anaesthesia. TRIAL REGISTRATION: The trial was registered at the Chinese Clinical Trial Registry (ChiCTR) ( www.chictr.org ), registration number was ChiCTR1900022327 (The website link: https://www.chictr.org.cn/showproj.html?proj=37271 ) and the date of trial registration was in April 5, 2019. This study was performed in accordance with the Declaration of Helsinki and approved by the Research Ethics Committee of Women's Hospital, Zhejiang University School of Medicine (20,180,120).

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INTRODUCTION: Catheterisation is the gold standard used to evaluate pulmonary blood flow in patients with a Blalock-Thomas-Taussig shunt. It involves risk and cannot be performed frequently. This study aimed to evaluate if echocardiographic measurements obtained in a clinical setting correlate with catheterisation-derived pulmonary blood flow in patients with a Blalock-Thomas-Taussig shunt as the sole source of pulmonary blood flow. METHODS: Chart review was performed retrospectively on consecutive patients referred to the catheterisation lab with a Blalock-Thomas-Taussig shunt. Echocardiographic parameters included peak, mean, and diastolic gradients across the Blalock-Thomas-Taussig shunt and forward and reverse velocity time integral across the distal transverse aorta. In addition to direct correlations, we tested a previously published formula for pulmonary blood flow calculated as velocity time integral across the shunt × heart rate × Blalock-Thomas-Taussig shunt area. Catheterisation parameters included pulmonary and systemic blood flow as calculated by the Fick principle. RESULTS: 18 patients were included. The echocardiography parameters and oxygen saturation did not correlate with catheterisation-derived pulmonary blood flow, systemic blood flow, or the ratio of pulmonary to systemic blood flow. As the ratio of reverse to forward velocity time integral across the transverse aorta increased, the probability of shunt stenosis decreased. CONCLUSION: Echocardiographic measurements obtained outside the catheterisation lab do not correlate with catheterisation-derived pulmonary blood flow. The ratio of reverse to forward velocity time integral across the transverse aortic arch may be predictive of Blalock-Thomas-Taussig shunt narrowing; this finding should be investigated further.

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This study aims to evaluate the effect of assessing velocity time integral at different locations across ventricular outflow tracts for calculating cardiac output (CO) in neonates. Velocity time integral (VTI) and CO were measured at 3 different locations across right and left ventricular outflow tracts using transthoracic echocardiography in healthy term neonates without any major congenital heart disease. ANOVA with Bonferroni correction was used to determine the differences between the VTI and CO sampled at these three locations. Forty-one neonates met inclusion criteria with mean gestational age of 38.6 ± 1 weeks and mean birth weight of 3155 ± 463 g. The median hours after birth when echocardiography was obtained was 23 h (range 11-68 h after birth). Left CO were 121 ± 30 mL/kg/min, 155 ± 38 mL/kg/min, and 176 ± 36 mL/kg/min measured below the valve, hinges of the valve, and tip of the valve, respectively. Right CO were 197 ± 73 mL/kg/min, 270 ± 83 mL/kg/min, and 329 ± 104 mL/kg/min measured below the valve, hinges of the valve, and tip of the valve, respectively. A statistically significant difference (P < 0.001) was found in the VTI and CO measured at the 3 different locations across both left and right ventricular outflow tracts.     Conclusions: There is a significant difference in measurements of VTI and CO depending on the location of Doppler gate sampling across the ventricular outflow tracts. Consistency and precision in Doppler gate location are essential for measuring VTI and calculating CO while assessing changes in hemodynamic status in critically ill infants. What is Known: • Targeted Neonatal Echocardiography is increasingly applied to measure cardiac output in critically ill neonates and serial assessments are performed to assess the trend in changes in cardiac output. • Noninvasive measurement using velocity time integral to calculate cardiac output is commonly performed. However, location of Doppler sample gate to measure ventricular outflow tract velocity time integral is not consistent. What is New: • Statistically significant changes in measured velocity time integral and cardiac output are noted based on the location of Doppler gate sampling. • To monitor the cardiac output for trending, it is important to be consistent with regards to the location of the Doppler sample gate to assess changes in cardiac output in critically ill newborns.

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BACKGROUND: Prophylactic vasopressor infusion can effectively assist with fluid loading to prevent spinal anesthesia-induced hypotension. However, the ideal dose varies widely among individuals. We hypothesized that hypotension-susceptible patients requiring cesarean section (C-section) could be identified using combined ultrasound parameters to enable differentiated prophylactic medical interventions. METHODS: This prospective observational trial was carried out within a regional center hospital for women and children in Sichuan Province, China. Singleton pregnant women undergoing combined spinal-epidural anesthesia for elective C-sections were eligible. Women with contraindications to spinal anesthesia or medical comorbidities were excluded. Velocity time integral (VTI) and left ventricular end-diastolic area (LVEDA) in the supine and left lateral positions were measured on ultrasound before anesthesia. Stroke volume, cardiac output, and the percentage change (%) in each parameter between two positions were calculated. Vital signs and demographic data were recorded. Spinal anesthesia-induced hypotension was defined as a mean arterial pressure decrease of > 20% from baseline. The area under the receiver operating characteristic curve (AUROC) was used to analyze the associations of ultrasound measurements, vital signs, and demographic characteristics with spinal anesthesia-induced hypotension. This exploratory study did not have a predefined outcome; however, various parameter combinations were compared using the AUROC to determine which combined parameters had better predictive values. RESULTS: Patients were divided into the normotension (n = 31) and hypotension groups (n = 57). A combination of heart rate (HR), LVEDAs, and VTI% was significantly better at predicting hypotension than was HR (AUROC 0.827 vs. 0.707, P = 0.020) or LVEDAs (AUROC 0.827 vs. 0.711, P = 0.039) alone, but not significantly better than VTI% alone (AUROC 0.827 vs. 0.766, P = 0.098). CONCLUSION: The combined parameters of HR and LVEDAs with VTI% may predict spinal anesthesia-induced hypotension more precisely than the single parameters. Future research is necessary to determine whether this knowledge improves maternal and neonatal outcomes. TRIAL REGISTRATION: ChiCTR1900025191.

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The velocity time integral (VTI) is a clinical Doppler ultrasound measurement of blood flow, measured by the area under the wave curve and equivalent to the distance traveled by the blood. This retrospective study assessed the middle cerebral artery (MCA) VTI of fetuses in pregnancies complicated by maternal alloimmunization. Doppler indices of the MCA were retrieved from electronic medical records. Systolic deceleration-diastolic time, systolic acceleration time, VTI, and peak systolic velocity (PSV) were measured at 16-40 weeks gestation. Cases with PSV indicating fetal anemia (cutoff 1.5 MoM) and normal PSV were compared. The study included 255 Doppler ultrasound examinations. Of these, 41 were at 16-24 weeks (group A), 100 were at 25-32 weeks (group B), and 114 were at 33-40 weeks (group C). VTI increased throughout gestation (5.5 cm, 8.6 cm, and 12.1 cm in groups A, B, and C, respectively, p = 0.003). VTI was higher in waveforms calculated to have MCA-PSV ≥ 1.5 MoM compared to those with MCA-PSV < 1.5 MoM (9.1 cm vs. 14.1 cm, respectively, p < 0.001), as was VTI/s (22.04 cm/s vs. 33.75 cm/s, respectively; p < 0.001). The results indicate that the MCA VTI increases significantly among fetuses with suspected anemia, indicating higher perfusion of hemodiluted blood to the brain. This feasible measurement might provide a novel additional marker for the development of fetal anemia.

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BACKGROUND: Pulmonary stenosis (PS) usually is evaluated using echocardiography. A multiparametric approach, in addition to the maximum pressure gradient (PG), might be indicated to better characterize PS severity and address its management. HYPOTHESIS/OBJECTIVES: Our hypothesis was that right heart size and function are associated with echocardiographic and clinical severity of pulmonary stenosis in dogs. ANIMALS: Client-owned dogs with PS. METHODS: Prospective, multicenter, observational study. Enrolled dogs underwent complete echocardiographic examination. Associations among right heart echocardiographic variables, PS transvalvular PG >80 mm Hg and presence of clinical signs (exercise intolerance, syncope, right-sided congestive failure, or some combination of these) were assessed using logistic regression analysis. RESULTS: Eighty-eight dogs with PS. Twenty-eight dogs were symptomatic. Increased right ventricular end-diastolic free wall thickness (odds ratio [OR] > 100; 95% confidence interval [95%CI], 50- > 100; P = .01) and decreased aorta-to-pulmonary artery velocity time integral ratio (OR, < 0.001; 95%CI, 0.0-0.001; P = .005) were independently associated with PS PG >80 mm Hg. Decreased tricuspid annular plane systolic excursion (OR, 0.35; 95%CI, 0.15-0.77; P = .01) and increased right ventricular end-diastolic area (OR, 1.4; 95%CI, 1.08-2.02; P = .01) were independently associated with clinical severity. CONCLUSION AND CLINICAL IMPORTANCE: Structural and functional right heart echocardiographic variables are associated with echocardiographic and clinical severity in dogs with PS. A multiparametric approach is advised to better assess PS severity.

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Objective We aimed to assess the usefulness of using the right ventricle outflow tract (RVOT) velocity-time integral (VTI) for echocardiographic monitoring of cardiac output compared to the gold standard, the VTI along the left ventricle outflow tract (LVOT). Design Prospective observational study. Setting A tertiary intensive care unit. Patients 100 consecutive patients. Interventions: echocardiographic monitoring in critically ill patients. Main variables of interest We used intraclass correlation coefficients (ICC) to compare echocardiographic measurements of LVOT VTI through apical window with RVOT VTI through the parasternal and modified subcostal windows and to assess interobserver reproducibility. Preplanned post hoc analyses compared the ICC between ventilated and nonventilated patients. Results At the time of echocardiography, 44 (44%) patients were mechanically ventilated and 28 (28%) were receiving vasoactive drugs. Good-quality measurements were obtained through the parasternal short-axis and/or apical views in 81 (81%) patients and in 100 (100%) patients through the subcostal window. Consistency with LVOT VTI was moderate for RVOT VTI measured from the modified subcostal view (ICC 0.727; 95%CI: 0.62–0.808) and for RVOT VTI measured from the transthoracic view (0.715; 95%CI: 0.59–0.807). Conclusions Measurements of RVOT VTI are moderately consistent with measurements of LVOT VTI. Adding the modified subcostal window allows monitoring RVOT VTI in all the patients of this selected cohort, even those under mechanical ventilation (AU)

Objetivo Valorar la utilidad de la integral velocidad-tiempo (IVT) del tracto de salida del ventrículo derecho (TSVD) para la monitorización del gasto cardíaco comparado con el gold standard, el IVT del tracto de salida del ventrículo izquierdo (TSVI). Diseño Estudio prospectivo observacional. Ámbito UCI de un hospital terciario. Paciente Cien pacientes consecutivos. Intervenciones Ecocardiografías realizadas para monitorización hemodinámica. Variables de interés principales Usamos el coeficiente de correlación intraclase (CCI) para comparar las mediciones de IVT TSVI a través de la ventana apical con el IVT TSVD a través de la ventana paraesternal y subcostal modificada y la reproducibilidad interobservador. Se planeó un análisis post hoc para comparar los resultados en pacientes ventilados con no ventilados. Resultados En el momento de la ecografía, 44 (44%) pacientes estaban en ventilación mecánica y 28 (28%) recibían fármacos vasoactivos. Mediciones de buena calidad se obtuvieron a través de la ventana paraesternal o apical en 81 (81%) pacientes, y en 100 (100%) con la ventana subcostal modificada. La consistencia del IVT TSVI fue moderada con el IVT TSVD medido con la ventana subcostal modificada (CCI 0,727; IC 95%: 0,62-0,808) y la transtorácica (0,715; IC 95%: 0,59-0,807). Conclusiones El IVT TSVD presenta una consistencia moderada cuando se compara con el IVT TSVI. Añadir la ventana subcostal modificada permite monitorizar el IVT TSVD en todos los pacientes de esta cohorte, incluso aquellos con ventilación mecánica (AU)

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BACKGROUND: Progression to combined post- and pre-capillary pulmonary hypertension (PH) provides prognostic information in human patients with post-capillary PH. Pulmonary vascular resistance estimated by echocardiography (PVRecho) is useful for the stratification of dogs with myxomatous mitral valve disease (MMVD) and detectable tricuspid regurgitation. OBJECTIVES: To evaluate the prognostic value of PVRecho in dogs with MMVD. ANIMALS: Fifty-four dogs with MMVD and detectable tricuspid regurgitation. METHODS: Prospective cohort study. All dogs underwent echocardiography. The PVRecho was calculated based on tricuspid regurgitation and the velocity-time integral of the pulmonary artery flow. To evaluate the influence of echocardiographic variables on cardiac-related deaths, Cox proportional hazard analysis was performed. Additionally, Kaplan-Meier curves classified by PVRecho tertiles were made and compared using log-rank tests to evaluate the influence of PVRecho on all-cause mortality and cardiac-related death. RESULTS: The median follow-up time was 579 days. Forty-one dogs with MMVD (PH severity [number]: no or mild, 21/33; moderate, 11/11; severe, 9/10) died during the study. In the multivariable Cox proportional hazard analysis adjusted for age, sildenafil administration, and American College of Veterinary Internal Medicine stage of MMVD, left atrial to aortic diameter ratio and PVRecho remained significant (adjusted hazard ratio [95% confidence interval]: 1.2 [1.1-1.3] and 2.1 [1.6-3.0], respectively). Higher PVRecho showed a significant association with lower survival rates. CONCLUSIONS AND CLINICAL IMPORTANCE: Left atrial enlargement and high PVRecho were independent prognostic factors in dogs with MMVD and detectable tricuspid regurgitation.

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