The Use of Point-of-Care Ultrasound to Evaluate Pulsus Paradoxus in Children With Asthma.

Pulsus paradoxus (PP) is defined as a fall of systolic blood pressure of greater than 10 mm Hg during the inspiratory phase of respiration. Measurement of PP is recommended by national and international asthma guidelines as an objective measure of asthma severity but is rarely used in clinical practice. Cardiac point-of-care ultrasound with pulsed wave Doppler imaging measuring respiratory-phasic changes of mitral valve inflow velocities is well described in cardiac tamponade as "sonographic" PP. We present 10 cases of acute asthma presenting to an emergency department showing the finding of sonographic determined PP in the apical 4-chamber view of the heart on pulsed wave Doppler imaging.

Intervendor Discordance of Fetal and Neonatal Myocardial Tissue Doppler and Speckle-Tracking Measurements.

BACKGROUND: Fetal and neonatal studies report a wide range of cardiac parameters derived by pulsed-wave Doppler tissue imaging (DTI) and two-dimensional speckle-tracking echocardiographic (STE) imaging. The use of different ultrasound systems and their vendor-specific software compromises the ability to compare echocardiographic findings among various studies. The aim of this study was to evaluate intervendor reproducibility as well as intra- and interobserver repeatability of DTI and STE measurements in normal-term fetuses and neonates. METHODS: A prospective study was conducted of term fetuses (n = 196) from uncomplicated pregnancies assessed days before the onset of labor and a few hours after birth. Fetal and neonatal DTI and STE parameters were obtained and analyzed using vendor-specific software on three ultrasound systems: Toshiba Aplio MX versus GE Vivid E9 and GE Vivid E9 versus Philips EPIQ. A reproducibility study in fetuses and neonates (n = 118) was performed by systematic scanning with head-to-head comparison. RESULTS: DTI reproducibility showed moderate to good correlation, with good agreement for fetuses and neonates on Toshiba versus GE (intraclass correlation coefficient [ICC] = 0.4-0.8). Correlation of DTI measurements on GE versus Philips was poor to moderate for fetuses (ICC = 0.1-0.6) and moderate to good for neonates (ICC = 0.5-0.8), with wider limits of agreement. Fetal and neonatal STE parameters revealed very poor correlation (ICC = 0.1-0.3) and agreement among ultrasound vendors. Intra- and interobserver repeatability demonstrated good to excellent correlation of all fetal and neonatal DTI and STE measurements, with good agreement irrespective of the ultrasound platform used. CONCLUSIONS: These findings demonstrate reliable assessment of fetal and neonatal DTI and STE measurements when performed on the same ultrasound platform, whereas ultrasound machines and software from different vendors give significantly divergent estimates of DTI and STE parameters in fetuses and neonates. These intervendor discrepancies have significant clinical and research implications and should be considered when interpreting and comparing study findings, establishing reference standards, or performing systematic reviews.

Prognostic Value of a Simple Echocardiographic Parameter, the Right Ventricular Systolic to Diastolic Duration Ratio, in Patients with Advanced Heart Failure with Non-Ischemic Dilated Cardiomyopathy.

The prognostic value of the right ventricular (RV) systolic to diastolic duration ratio (S/D ratio) in patients with advanced heart failure is not clear.We enrolled 45 patients with DCM (40 ± 13 years, 33 male) who were admitted to our hospital for evaluation or treatment of heart failure. The RV systolic and diastolic durations were measured using continuous Doppler imaging of tricuspid regurgitation, and the RV S/D ratio was calculated. Cardiac events were defined as cardiac death or left ventricular assist device implantation within the first year. Twenty-eight cardiac events occurred. The RV S/D ratio was significantly higher in the event group than in the event-free group (1.8 ± 0.8 versus 1.2 ± 0.5, P = 0.008). Univariate analysis showed that the RV S/D ratio, plasma brain natriuretic peptide concentration, left atrial volume index, and mitral deceleration time were associated with these events. Receiver operating characteristic curve analysis revealed that the optimal RV S/D cutoff value to predict events was 1.2 (sensitivity 79%, specificity 65%, area under the curve 0.745). Kaplan-Meier analysis indicated a significantly higher event rate in patients with an RV S/D ratio > 1.2 (log-rank test, P = 0.003). The addition of an RV S/D ratio > 1.2 improved the prognostic utility of a model that included conventional variables (P = 0.014).In patients with advanced heart failure with DCM, the RV S/D ratio was higher in patients with events than in those without events. The addition of the RV S/D ratio to conventional parameters may provide better prognostic information.

Dynamic fetal cardiovascular magnetic resonance imaging using Doppler ultrasound gating.

BACKGROUND: Fetal cardiovascular magnetic resonance (CMR) imaging may provide a valuable adjunct to fetal echocardiography in the evaluation of congenital cardiovascular pathologies. However, dynamic fetal CMR is difficult due to the lack of direct in-utero cardiac gating. The aim of this study was to investigate the effectiveness of a newly developed Doppler ultrasound (DUS) device in humans for fetal CMR gating. METHODS: Fifteen fetuses (gestational age 30-39 weeks) were examined using 1.5 T CMR scanners at three different imaging sites. A newly developed CMR-compatible DUS device was used to generate gating signals from fetal cardiac motion. Gated dynamic balanced steady-state free precession images were acquired in 4-chamber and short-axis cardiac views. Gating signals during data acquisition were analyzed with respect to trigger variability and sensitivity. Image quality was assessed by measuring endocardial blurring (EB) and by image evaluation using a 4-point scale. Left ventricular (LV) volumetry was performed using the single-plane ellipsoid model. RESULTS: Gating signals from the fetal heart were detected with a variability of 26 ± 22 ms and a sensitivity of trigger detection of 96 ± 4%. EB was 2.9 ± 0.6 pixels (4-chamber) and 2.5 ± 0.1 pixels (short axis). Image quality scores were 3.6 ± 0.6 (overall), 3.4 ± 0.7 (mitral valve), 3.4 ± 0.7 (foramen ovale), 3.6 ± 0.7 (atrial septum), 3.7 ± 0.5 (papillary muscles), 3.8 ± 0.4 (differentiation myocardium/lumen), 3.7 ± 0.5 (differentiation myocardium/lung), and 3.9 ± 0.4 (systolic myocardial thickening). Inter-observer agreement for the scores was moderate to very good (kappa 0.57-0.84) for all structures. LV volumetry revealed mean values of 2.8 ± 1.2 ml (end-diastolic volume), 0.9 ± 0.4 ml (end systolic volume), 1.9 ± 0.8 ml (stroke volume), and 69.1 ± 8.4% (ejection fraction). CONCLUSION: High-quality dynamic fetal CMR was successfully performed using a newly developed DUS device for direct fetal cardiac gating. This technique has the potential to improve the utility of fetal CMR in the evaluation of congenital pathologies.

Evaluation of a Portable Doppler Ultrasound Gating Device for Fetal Cardiac MR Imaging: Initial Results at 1.5T and 3T.

PURPOSE: Fetal cardiac MRI has the potential to play an important role in the assessment of fetal cardiac pathologies, but it is up to now not feasible due to a missing gating method. The purpose of this work was the evaluation of Doppler ultrasound (DUS) for external fetal cardiac gating with regard to compatibility, functionality, and reliability. Preliminary results were assessed performing fetal cardiac MRI. METHODS: An MRI conditional DUS device was developed to obtain a gating signal from the fetal heart. The MRI compatibility was evaluated at 1.5T and 3T using B1 field maps and gradient echo images. The quality and sensitivity of the DUS device to detect the fetal heart motion for cardiac gating were evaluated outside the MRI room in 15 fetuses. A dynamic fetal cardiac phantom was employed to evaluate distortions of the DUS device and gating signal due to electromagnetic interferences at 1.5T and 3T. In the first in vivo experience, dynamic fetal cardiac images were acquired in four-chamber view at 1.5T and 3T in two fetuses. RESULTS: The maximum change in the B1 field and signal intensity with and without the DUS device was <6.5% for 1.5T and 3T. The sensitivity of the DUS device to detect the fetal heartbeat was 99.1%. Validation of the DUS device using the fetal cardiac phantom revealed no electromagnetic interferences at 1.5T or 3T and a high correlation to the simulated heart frequencies. Fetal cardiac cine images were successfully applied and showed good image quality. CONCLUSION: An MR conditional DUS gating device was developed and evaluated revealing safety, compatibility, and reliability for different field strengths. In a preliminary experience, the DUS device was successfully applied for in vivo fetal cardiac imaging at 1.5T and 3T.

Incremental value of right atrial strain for early diagnosis of hemodynamic deterioration in pulmonary hypertension: a new noninvasive tool for a more comprehensive diagnostic paradigma.

AIMS: Increased right atrial size is related to adverse prognosis in pulmonary hypertension. The potential incremental value of right atrial function assessment is still unclear. We tested the relationship between right atrial two-dimensional speckle-tracking echocardiography impairment and hemodynamic, functional and clinical deterioration in patients with pulmonary hypertension. METHODS: We prospectively evaluated 36 patients (27 female, 9 male; mean age 68 ±â€Š13 years) with suspected pulmonary hypertension undergoing right heart catheterization and 16 matched controls. All patients underwent baseline evaluation by New York Heart Association functional class, 6-min walking test, brain natriuretic peptide (BNP), and standard two-dimensional echocardiography in less than 48 h of right heart catheterization. Right atrial two-dimensional speckle-tracking echocardiography was assessed by averaging all segments in standard four-chamber apical view. RESULTS: Right atrial global integral strain was significantly lower in patients compared with controls (11.40 ±â€Š5.22% vs. 25.72 ±â€Š5.95 P < 0.001). Moreover, right atrial global strain, but not right atrial area or volume, was correlated with invasively measured cardiac index (CI) (r = 0.72; P < 0.0001) and pulmonary vascular resistances in all patients, even though stronger in subjects with precapillary pulmonary hypertension (r = -0.42, P = 0.018; r = -0.54, P = 0.007 respectively; P = 0.007). It was also correlated with New York Heart Association (P = 0.027), BNP (P = 0.002), and 6-min walking test (P = 0.006). After multivariate analysis including right atrial volume, tricuspid annular plane systolic excursion, left atrial strain, and BNP, right atrial global strain showed the strongest correlation with CI. Area under the curve optimal cutoff for predicting CI at least 2.4 l/min/m was 17% (area under the curve: 0.83, sensitivity: 90%, specificity: 54%). CONCLUSION: Right atrial global strain can identify right atrial functional impairment before structural changes and may be implemented in a comprehensive, noninvasive right heart assessment for diagnosis and follow-up of pulmonary hypertension patients.

Identification of the main determinants of abdominal aorta size: a screening by Pocket Size Imaging Device.

BACKGROUND: Ultrasound exam as a screening test for abdominal aorta (AA) can visualize the aorta in 99% of patients and has a sensitivity and specificity approaching 100% in screening settings for aortic aneurysm. Pocket Size Imaging Device (PSID) has a potential value as a screening tool, because of its possible use in several clinical settings. Our aim was to assess the impact of demographics and cardiovascular (CV) risk factors on AA size by using PSID in an outpatient screening. METHODS: Consecutive patients, referring for a CV assessment in a 6 months period, were screened. AA was visualized by subcostal view in longitudinal and transverse plans in order to determine the greatest anterior-posterior diameter. After excluding 5 patients with AA aneurysm, 508 outpatients were enrolled. All patients underwent a sequential assessment including clinical history with collection of CV risk factors, physical examination, PSID exam and standard Doppler echoc exam using a 2.5 transducer with harmonic capability, both by expert ultrasound operators, during the same morning. Standard echocardiography operators were blinded on PSID exam and viceversa. RESULTS: Diagnostic accuracy of AA size by PSID was tested successfully with standard echo machine in a subgroup (n = 102) (rho = 0.966, p < 0.0001). AA diameter was larger in men than in women and in ≥50 -years old subjects than in those <50 -years old (both p < 0.0001). AA was larger in patients with coronary artery disease (CAD) (p < 0.0001). By a multivariate model, male sex (p < 0.0001), age and body mass index (both p < 0.0001), CAD (p < 0.01) and heart rate (p = 0.018) were independent predictors of AA size (cumulative R 2 = 0.184, p < 0.0001). CONCLUSION: PSID is a reliable tool for the screening of determinants of AA size. AA diameter is greater in men and strongly influenced by aging and overweight. CAD may be also associated to increased AA diameter.

Participants' above-chance recognition of own-heart sound combined with poor metacognitive awareness suggests implicit knowledge of own heart cardiodynamics.

Mounting evidence suggests that interoceptive signals are fundamentally important for the experience of the self. Thus far, studies on interoception have mainly focused on the ability to monitor the timing of ongoing heartbeats and on how these influence emotional and self-related processes. However, cardiac afferent signalling is not confined to heartbeat timing and several other cardiac parameters characterize cardiodynamic functioning. Building on the fact that each heart has its own self-specific cardio-dynamics, which cannot be expressed uniquely by heart rate, we devised a novel task to test whether people could recognize the sound of their own heart even when perceived offline and thus not in synchrony with ongoing heartbeats. In a forced-choice paradigm, participants discriminated between sounds of their own heartbeat (previously recorded with a Doppler device) versus another person's heart. Participants identified the sound of their own heart above chance, whereas their metacognition of performance - as calculated by contrasting performance against ratings of confidence - was considerably poorer. These results suggest an implicit access to fine-grained neural representations of elementary cardio-dynamic parameters beyond heartbeat timing.

Comparison of Two Different Ultrasound Systems for the Evaluation of Tissue Doppler Velocities in Fetuses.

INTRODUCTION: Recent studies have reported variations of up to 30% between different ultrasound machines for tissue Doppler imaging (TDI), a problem that can significantly impact clinical diagnosis, patient management and research studies. The objective of this study was to assess repeatability and agreement between fetal myocardial peak velocities evaluated by TDI with two different ultrasound systems. MATERIALS AND METHODS: Systolic (S'), early (E') and late (A') diastolic myocardial peak velocities at mitral and tricuspid annuli as well as at the basal septum were evaluated by spectral TDI in 150 fetuses using two different ultrasound systems: Siemens Antares (Siemens Medical Systems, Malvern, Pa., USA) and Vivid Q (General Electric Healthcare, Horten, Norway). A method comparison study was performed, calculating intraclass correlation coefficients (ICC), and agreement was assessed by Bland-Altman plots. RESULTS: Annular peak velocities showed lower values when measured by Vivid Q compared to values measured by Siemens Antares. ICC ranged from 0.07 (septal S') to 0.33 (right A'), showing very poor repeatability for clinical application. Agreement between the two systems was also poor, with high coefficients of variation for all measurements. CONCLUSIONS: Fetal annular peak velocities obtained with different ultrasound systems are not directly comparable. This is consistent with previous data in adults and warrants the need of system-specific reference values, suggesting that the same ultrasound machine should be used for longitudinal follow-up.

In vitro evaluation of an ultrasonic cardiac output monitoring (USCOM) device.

Non-invasive cardiac output monitoring techniques provide high yield, low risk mechanisms to identify and individually treat shock in the emergency setting. The non-invasive ultrasonic cardiac output monitoring (USCOM) device uses an ultrasound probe applied externally to the chest; however limitations exist with previous validation strategies. This study presents the in vitro validation of the USCOM device against calibrated flow sensors and compares user variability in simulated healthy and septic conditions. A validated mock circulation loop was used to simulate each condition with a range of cardiac outputs (2-10 l/min) and heart rates (50-95 bpm). Three users with varying degrees of experience using the USCOM device measured cardiac output and heart rate by placing the ultrasound probe on the mock aorta. Users were blinded to the condition, heart rate and cardiac output which were randomly generated. Results were reported as linear regression slope (ß). All users estimated heart rate in both conditions with reasonable accuracy (ß = 0.86-1.01), while cardiac output in the sepsis condition was estimated with great precision (ß = 1.03-1.04). Users generally overestimated the cardiac output in the healthy simulation (ß = 1.07-1.26) and reported greater difficulty estimating reduced cardiac output compared with higher values. Although there was some variability between users, particularly in the healthy condition (P < 0.01), all estimations were within a clinically acceptable range. In this study the USCOM provided a suitable measurement of cardiac output and heart rate when compared with our in vitro system. It is a promising technique to assist with the identification and treatment of shock.

Validation of high temporal resolution spiral phase velocity mapping of temporal patterns of left and right coronary artery blood flow against Doppler guidewire.

BACKGROUND: Temporal patterns of coronary blood flow velocity can provide important information on disease state and are currently assessed invasively using a Doppler guidewire. A non-invasive alternative would be beneficial as it would allow study of a wider patient population and serial scanning. METHODS: A retrospectively-gated breath-hold spiral phase velocity mapping sequence (TR 19 ms) was developed at 3 Tesla. Velocity maps were acquired in 8 proximal right and 15 proximal left coronary arteries of 18 subjects who had previously had a Doppler guidewire study at the time of coronary angiography. Cardiovascular magnetic resonance (CMR) velocity-time curves were processed semi-automatically and compared with corresponding invasive Doppler data. RESULTS: When corrected for differences in heart rate between the two studies, CMR mean velocity through the cardiac cycle, peak systolic velocity (PSV) and peak diastolic velocity (PDV) were approximately 40 % of the peak Doppler values with a moderate - good linear relationship between the two techniques (R(2): 0.57, 0.64 and 0.79 respectively). CMR values of PDV/PSV showed a strong linear relationship with Doppler values with a slope close to unity (0.89 and 0.90 for right and left arteries respectively). In individual vessels, plots of CMR velocities at all cardiac phases against corresponding Doppler velocities showed a consistent linear relationship between the two with high R(2) values (mean +/-SD: 0.79 +/-.13). CONCLUSIONS: High temporal resolution breath-hold spiral phase velocity mapping underestimates absolute values of coronary flow velocity but allows accurate assessment of the temporal patterns of blood flow.

The effect of aorta unfolding and remodelling on oesophageal Doppler readings as probe depth is varied.

BACKGROUND: The thoracic aorta elongates and unfolds with advancing age. Lateral displacement and tortuosity of the descending part may affect oesophageal Doppler monitoring (ODM) readings because probe alignment becomes slanted. This investigation aimed to relate aortic displacement as it appears on the chest radiograph with variations in ODM readings as the probe is inserted to different depths. METHODS: In anaesthetized patients a series of three to five ODM stroke volume (SV) readings were obtained at insertion depths of 35-45 cm during stable haemodynamics. The coefficient of variation (CV=standard deviation/mean %) was calculated. The degree of descending aorta unfolding was measured by (i) lateral displacement (LD), that is, the difference in the maximum and minimum distances between the midline and para-aortic line; and (ii) curvature angle (CA), the angle formed by a tangential line from the intersection of the para-aortic line and the diaphragm to its curve with the vertical line. RESULTS: Data from 70 patients were analysed. The median CV of SV readings was 14% (range 4-48). Variation between ODM readings, shown by the CV of SV readings, increased linearly with aortic unfolding: R2=0.44 for LD and R2=0.60 for CA. Patients with a CA ≤15° were younger and had significantly lower CVs of ODM readings than those with a CA >15° (P=0.001). Age and hypertension was associated with increased CA. CONCLUSIONS: Increased lateral displacement and tortuosity of the descending aorta reduces the reliability of ODM measurements as probe depth is varied, especially with aging.

Goal-Directed Fluid Therapy Guided by Cardiac Monitoring During High-Risk Abdominal Surgery in Adult Patients: Cost-Effectiveness Analysis of Esophageal Doppler and Arterial Pulse Pressure Waveform Analysis.

BACKGROUND: Several minimally invasive techniques for cardiac output monitoring such as the esophageal Doppler (ED) and arterial pulse pressure waveform analysis (APPWA) have been shown to improve surgical outcomes compared with conventional clinical assessment (CCA). OBJECTIVE: To evaluate the cost-effectiveness of these techniques in high-risk abdominal surgery from the perspective of the French public health insurance fund. METHODS: An analytical decision model was constructed to compare the cost-effectiveness of ED, APPWA, and CCA. Effectiveness data were defined from meta-analyses of randomized clinical trials. The clinical end points were avoidance of hospital mortality and avoidance of major complications. Hospital costs were estimated by the cost of corresponding diagnosis-related groups. RESULTS: Both goal-directed therapy strategies evaluated were more effective and less costly than CCA. Perioperative mortality and the rate of major complications were reduced by the use of ED and APPWA. Cost reduction was mainly due to the decrease in the rate of major complications. APPWA was dominant compared with ED in 71.6% and 27.6% and dominated in 23.8% and 20.8% of the cases when the end point considered was "major complications avoided" and "death avoided," respectively. Regarding cost per death avoided, APPWA was more likely to be cost-effective than ED in a wide range of willingness to pay. CONCLUSIONS: Cardiac output monitoring during high-risk abdominal surgery is cost-effective and is associated with a reduced rate of hospital mortality and major complications, whatever the device used. The two devices evaluated had negligible costs compared with the observed reduction in hospital costs. Our comparative studies suggest a larger effect with APPWA that needs to be confirmed by further studies.

Effects of fluid administration on arterial load in septic shock patients.

PURPOSE: To determine the effects of fluid administration on arterial load in critically ill patients with septic shock. METHODS: Analysis of septic shock patients monitored with an oesophageal Doppler and equipped with an indwelling arterial catheter in whom a fluid challenge was performed because of the presence of systemic hypoperfusion. Measures of arterial load [systemic vascular resistance, SVR = mean arterial pressure (MAP)/cardiac output (CO); net arterial compliance, C = stroke volume (SV)/arterial pulse pressure; and effective arterial elastance, Ea = 90% of systolic arterial pressure/SV] were studied both before and after volume expansion (VE). RESULTS: Eighty-one patients were analysed, 54 (67%) increased their CO by at least 10% after VE (preload responders). In the whole population, 29 patients (36%) increased MAP by at least 10 % from preinfusion level (pressure responders). In the preload responder group, only 24 patients (44%) were pressure responders. Fluid administration was associated with a significant decrease in Ea [from 1.68 (1.11-2.11) to 1.57 (1.08-1.99) mmHg/mL; P = 0.0001] and SVR [from 1035 (645-1483) to 928 (654-1452) dyn s cm(-5); P < 0.01]. Specifically, in preload responders in whom arterial pressure did not change, VE caused a reduction in Ea from 1.74 (1.22-2.24) to 1.55 (1.24-1.86) mmHg/mL (P < 0.0001), affecting both resistive [SVR: from 1082 (697-1475) to 914 (624-1475) dyn s cm(-5); P < 0.0001] and pulsatile [C: from 1.11 (0.84-1.49) to 1.18 (0.99-1.44) mL/mmHg; P < 0.05] components. There was no relationship between preinfusion arterial load parameters and VE-induced increase in arterial pressure. CONCLUSION: Fluid administration significantly reduced arterial load in critically patients with septic shock and acute circulatory failure, even when increasing cardiac output. This explains why some septic patients increase their cardiac output after fluid administration without improving blood pressure.

Focused ultrasound of the pleural cavities and the pericardium by nurses after cardiac surgery.

OBJECTIVES: We aimed to study the feasibility and reliability of focused ultrasound (US) examinations to quantify pericardial (PE)- and pleural effusion (PLE) by a pocket-size imaging device (PSID) performed by nurses in patients early after cardiac surgery. DESIGN: After a 3-month training period, with cardiologists as supervisors, two nurses examined 59 patients (20 women) with US using a PSID at a median of 5 days after cardiac surgery. The amount of PE and PLE was classified in four categories by US (both) and chest x-ray (PLE only). Echocardiography, including US of the pleural cavities, by experienced cardiologists was used as reference. RESULTS: Focused US by the nurses was more sensitive than x-ray to detect PLE. The correlations of the quantification of PE and PLE by the nurses and reference was r (95% confidence interval) 0.76 (0.46-0.89) and 0.81 (0.73-0.89), both p < 0.001. PE and PLE were drained in one and six (eight cavities) patients, all classified as large amount by the nurses. CONCLUSIONS: Cardiac nurses were able to obtain reliable measurements and quantification of both PE and PLE bedside by focused US and outperform the commonly used chest x-ray regarding PLE after cardiac surgery.

2-D left ventricular flow estimation by combining speckle tracking with Navier-Stokes-based regularization: an in silico, in vitro and in vivo study.

Despite the availability of multiple ultrasound approaches to left ventricular (LV) flow characterization in two dimensions, this technique remains in its childhood and further developments seem warranted. This article describes a new methodology for tracking the 2-D LV flow field based on ultrasound data. Hereto, a standard speckle tracking algorithm was modified by using a dynamic kernel embedding Navier-Stokes-based regularization in an iterative manner. The performance of the proposed approach was first quantified in synthetic ultrasound data based on a computational fluid dynamics model of LV flow. Next, an experimental flow phantom setup mimicking the normal human heart was used for experimental validation by employing simultaneous optical particle image velocimetry as a standard reference technique. Finally, the applicability of the approach was tested in a clinical setting. On the basis of the simulated data, pointwise evaluation of the estimated velocity vectors correlated well (mean r = 0.84) with the computational fluid dynamics measurement. During the filling period of the left ventricle, the properties of the main vortex obtained from the proposed method were also measured, and their correlations with the reference measurement were also calculated (radius, r = 0.96; circulation, r = 0.85; weighted center, r = 0.81). In vitro results at 60 bpm during one cardiac cycle confirmed that the algorithm properly measures typical characteristics of the vortex (radius, r = 0.60; circulation, r = 0.81; weighted center, r = 0.92). Preliminary qualitative results on clinical data revealed physiologic flow fields.

Handheld ultrasound versus physical examination in patients referred for transthoracic echocardiography for a suspected cardiac condition.

OBJECTIVES: The purpose of this study was to test the hypothesis that handheld ultrasound (HHU) provides a more accurate diagnosis than physical examination in patients with suspected cardiovascular abnormalities and that its use thus reduces additional testing and overall costs. BACKGROUND: Despite the limitations of physical examination and the demonstrated superiority of HHU for detecting cardiac abnormalities, it is not routinely used for the bedside diagnosis of cardiac conditions. METHODS: Patients referred for a standard echocardiogram for common indications (cardiac function, murmur, stroke, arrhythmias, and miscellaneous) underwent physical examination and HHU by different cardiologists, who filled out a form that also included suggestions for additional testing, if necessary, based on their findings. RESULTS: Of 250 patients, 142 had an abnormal finding on standard echocardiogram. Of these, HHU correctly identified 117 patients (82%), and physical examination correctly identified 67 (47%, p < 0.0001). HHU was superior to physical examination (p < 0.0001) for both normal and abnormal cardiac function. It was also superior to physical examination in correctly identifying the presence of substantial valve disease (71% vs. 31%, p = 0.0003) and in identifying miscellaneous findings (47% vs. 3%, p < 0.0001). Of 108 patients without any abnormalities on standard echocardiography, further testing was suggested for 89 (82%) undergoing physical examination versus only 60 (56%) undergoing HHU (p < 0.0001). Cost modeling showed that HHU had an average cost of $644.43 versus an average cost of $707.44 for physical examination. This yielded a savings of $63.01 per patient when HHU was used versus physical examination. CONCLUSIONS: When used by cardiologists, HHU provides a more accurate diagnosis than physical examination for the majority of common cardiovascular abnormalities. The finding of no significant abnormality on HHU is also likely to result in less downstream testing and thus potentially reduce the overall cost for patients being evaluated for a cardiovascular diagnosis.