Oxford Archaeology carried out a programme of archaeological investigation between 2014 and 2016 at Worthy Down Camp near Winchester. Apart from worked flint of possible Mesolithic date, the earliest ...archaeological evidence belonged to the late Neolithic period in the form ofa pit3 which contained finds that appeared to consist of mixed midden material relating to everyday subsistence and a specialised focus on pig-keeping. Two pits were dated to the middle Bronze Age. One pit contained the remains of at least five pottery vessels in Deverel-Rimbury style. The results of organic residue analysis suggest that some of the vessels had been used to process dairy products. Occupation resumed in the late Bronze Age after a hiatus. The features assigned to this period zvere dispersed but relate to settlement and farming activity. Parts of a large ditch shown by cropmarks to extend for several kilometres were uncovered in the excavation. Dating evidence suggests that the ditch continued to receive material into the late Roman period or beyond, but it is possible that the ditch was originally dug as a boundary or trackway in the Iron Age or earlier.
The present study examined cardiac characteristics of borderline hypertensive men with a positive parental history of hypertension. Hemodynamics in relation to left ventricular function and structure ...were evaluated in 15 borderline hypertensive men with a parental history of hypertension and in 20 normotensive control subjects with a negative parental history. Groups were matched in age, height, weight and percent body fat. Left ventricular mass and dimensions were measured by M-mode echocardiography, and left ventricular function was assessed by radionuclide ventriculography. Both groups had similar left ventricular mass, dimensions and wall thicknesses. In relation to control subjects, borderline hypertensive men had a significantly higher heart rate and blood pressure (BP) (p < 0.001), but a similar cardiac index. Borderline hypertensive men had a higher peripheral resistance index (p < 0.02), longer time to peak filling rate, and reduced cardiac efficiency, whereas they had higher contractility, minute and stroke work indexes than did control subjects (all p < 0.05); they also had higher diastolic BP (p < 0.03) during exercise, and sustained higher BP during recovery than did controls. Although this group of borderline hypertensive men did not have an altered cardiac anatomy, they had an increased vascular resistance, an altered diastolic function and a reduced cardiac efficiency while undergoing a greater work load. These cardiodynamic profiles are consistent with functional vascular changes and a parallel compensation by the heart.
The goals of the study described were: (1) to develop a computer-controlled regurgitant cardiac valve phantom, compatible with artifact-free magnetic resonance imaging (MRI) and color Doppler ...ultrasound (CFM); (2) to create regurgitant lesions in the phantom which appear similar to those detected clinically, (3) to measure physiologic pressure differences between chambers, compliances, and regurgitant fractions as seen in mild, moderate, and severe regurgitation. Mean chamber pressure differences ranged from 43-142 mmHg over the range of diseases simulated, regurgitant flow rates ranged from approximately 0.54-18.6 L/min, and compliance values ranged from 0.83 to 21.95 cc/mmHg fluid. No coherent or incoherent artifacts were observed in MRI or CFM images. Images showed a high degree of similarity to regurgitant lesions detected with each modality, confirming that all design goals were met. The system should allow extensive comparative analysis of Doppler ultrasound and MRI flow jets under a wide range of controllable hemodynamic conditions in future experiments.< >
A concentric beam Doppler ultrasonic flowmeter has been developed. This instrument has capacity for independent assessment of volumetric flow, as it determines flow cross-section area, stroke length, ...and pulse rate from the Doppler signals alone. The method is practically independent of the angle of interrogation. We used this device and obtained noninvasive estimates of cardiac output in 54 patients undergoing invasive assessment of cardiac output by thermodilution, Fick, or indicator dye methods (x). Correlations against pooled cardiac output reference standards ranged from r = .86 (y = .86x + 1.03) in 26 studies of high confidence to r = .45 (y = .30x + 2.62) in 17 studies under difficult conditions. The overall correlation was r = .68 (y = .63x + 1.49, n = 87). Noninvasive results of experienced and inexperienced operators were similar (r = .87). The instrument returned accurate assessments of heart rate (r = .83), but underestimated stroke length (r = .72) and appeared to be limited in the assessment of aortic diameters less than 28 or greater than 31 mm (r = .23). We conclude that stand-alone Doppler assessment of cardiac output is appealing and feasible, but difficult or impossible in many ICU scenarios. Further evolution of the concentric beam Doppler approach is needed and anticipated.
Aortic regurgitation and mitral stenosis are hemody-namically similar, insofar as both result in passive ventricular filling across a narrow orifice driven by a declining pressure gradient. Because ...mitral stenosis is successfully characterized by Doppler ultrasound determination of the velocity half-time, or time constant, aortic regurgitation might be quantified in an analogous fashion. Eighty-six patients with diverse causes of aortic regurgitation underwent continuous wave Doppler examination before cardiac catheterization or urgent aortic valve replacement. The Doppler velocity half-time was defined as the time required for the diastolic aortic regurgitation velocity profile to decay by 29%, whereas catheterization pressure half-time was calculated as the time required for transvalvular pressure to decay by 50%.
Doppler velocity and catheterization pressure half-times were linearly related (r = 0.91). Doppler velocity half-times were inversely related to regurgitant fraction (r = −0.88). Angiographic severity (1+ = mild to 4 + = severe) was also inversely related to pressure and velocity half-time; a Doppler half-time threshold of 400 ms separated mild (1 +, 2 +) from significant (3 +, 4 +) aortic regurgitation with high specificity (0.92) and predictive value (0.90). The Doppler velocity half-time was independent of pulse pressure, mean arterial pressure, ejection fraction and left ventricular end-diastolic pressure. Estimation of transvalvular aortic pressure half-time utilizing continuous wave Doppler ultrasound is a reliable and accurate method for the noninvasive evaluation of the severity of aortic regurgitation.
Aortic valve area was calculated noninvasively in 30 patients with aortic stenosis undergoing cardiac catheterization. Continuous wave Doppler ultrasound was employed to estimate the mean ...transvalvular pressure gradient. The mean left ventricular outflow tract flow velocity and cross-sectional area were determined from pulsed Doppler and two-dimensional ultrasound recordings. Electrical Irans-thoracic bioimpedance cardiography performed simultaneously with the ultrasonic study and repeated at the time of catheterization measured heart rate, systolic ejection period and cardiac output. These noninvasive data permitted calculation of aortic valve area using the Gorlin equation (range 0.21 to 1.75 cm2) and the continuity equation (range 0.25 to 1.9 cm2). Subsequent cardiac catheterization showed valve area to range from 0.21 to 1.75 cm2.
The mean Doppler pressure gradient estimate was highly predictive of the gradient measured at catheterization (r = +0.92, SEE = 10). Bioimpedance cardiac output measurements agreed with the average of Fick and indicator dye estimates (r = +0.90, SEE = 0.52). Valve area estimates utilizing continuous wave Doppler ultrasound and electrical bioimpedance were superior (r = +0.91, SEE = 0.12) to estimates obtained utilizing the continuity equation (r = +0.76, SEE = 0.29) and were more reliable in the detection of patients with severe aortic stenosis (9 of 11 versus 6 of 11).
These data show that 1) electrical bioimpedance methods accurately estimate cardiac output in the presence of aortic stenosis; 2) the hybridized bioimpedance-Doppler ultrasound method yields accurate estimates of aortic stenosis area; and 3) the speed, accuracy and cost-effectiveness of aortic stenosis evaluation may be unproved by this hybridized approach.
Contrast echocardiography has been shown to be a sensitive method for detecting patent foramen ovale in embolic stroke, implying paradoxical embolization. However, not all two-dimensional ...echocardiographic studies are of diagnostic quality, and direct evidence for paradoxical cerebral embolization remains lacking. We addressed these problems by simultaneously using transcranial Doppler ultrasound and contrast echocardiography to compare relative sensitivity and concordance in the detection of right-to-left vascular shunting. Forty-six patients with stroke, transient neurologic defect, or question of atrial septal defect underwent study at rest and during Valsalva strain. Two-dimensional echocardiography detected shunting in 26% at rest and 15% during Valsalva strain, whereas transcranial Doppler study returned rates of 41% and 41%, respectively. Concordance was 82% and 75%, respectively. Discordant studies almost always had evidence of paradoxical contrast embolization by transcranial Doppler and intermediate findings by two-dimensional echocardiography. Transcranial Doppler is a sensitive, unambiguous technique for the detection of anatomic substrates and target organ involvement in patients suspected to have paradoxical cerebral embolization.
Measurements of systolic ejection dynamics by impedance cardiography were compared with simultaneous Doppler echocardiography in normal subjects and coronary artery disease patients. Patients with ...chest pain admitted for elective coronary angiography were monitored by simultaneous impedance cardiography and Doppler echocardiography before, during, and after treadmill exercise. Ensemble-averaged ECG, impedance cardiogram (ICG), the first derivative of ICG (dZ/dt), and Doppler waveforms were analyzed to identify systolic ejection variables. The timing of aortic valve opening was well correlated (r = 0.78) the timing of peak ejection velocity was very well correlated (r = 0.86), and the timing of aortic valve closure was moderately correlated (r = 0.69 and r = 0.73) in these subjects. The thoracic electrical impedance acceleration and normalized impedance acceleration indices were moderately correlated with Doppler model acceleration (r = 0.74, r = 0.79). The impedance cardiogram waveforms are of complex origin and are related to both aortic blood velocity and aortic blood acceleration. Users of dZ/dt timing features for determining aortic valvular events might consider alternative impedance features to improve ejection time accuracy.
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