Stroke volumes and ventricular volumes determined from indicator dilution curves, Part 2 (original) (raw)
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Ventricular volumes determined from indicator dilution curves
Medical & Biological Engineering & Computing, 1979
A bolus of indicator substance injected into a ventricle or an atrium will be diluted in a stepwise manner according to the pulsatile nature of bloodflow. Provided the indicator is dispersed immediately and uniformly in the ventricle or atrium the time course of the indicator can be predicted. Dilution curves recorded in three dog experiments demonstrate a stepwise change of the indicator concentration in the ascending aorta following a bolus injection into the left atrium. The information thus retrieved is entered into equations describing the mathematical model in order to calculate the distribution volumes of the indicator in the left atrium and ventricle.
Nongeometric determination of right ventricular volumes from equilibrium blood pool scans
The American Journal of Cardiology, 1982
It has previously been shown that left ventricular volumes can be measured accurately from radionuclide gated blood pool scintigrams by quantitating the background-corrected and volume-normalized ventricular activity at end-diastole and end-systole. To determine if this same technique can be applied to the calculation of right ventricular volumes, simultaneous measurements of right ventricular stroke volume were performed using gated scintigraphy and the thermodilution technique in 60 patients without clinical or hemodynamic evidence of right-sided regurgitation. Three techniques for the acquisition of the radionuclide studies were evaluated. The best correlation between scintigraphic and thermodilutlon determinations of stroke volume was obtained for studies acquired with a 25' rotating slant hole collimator positioned in a 10 to 15" left anterior oblique projection with the collimator slant directed toward the cardiac apex along the axis of the interventricular septum: Thermodilution stroke volume = 4.2 (scintigraphic stroke volume)-I-10.3 ml (correlation coefficient [r]= 0.66; standard error of the estimate = 9.3 ml; probability [p] <O.OOOl). This scintigraphic acquisition technique was superior to (1) a straight bore collimator positioned in a septal projection (30 to 50" left anterior oblique with 15' caudal tilt), and (2) a 25' slant hole collimator positioned in a similar septal projection with the collimator slant directed caudally. This method was evaluated prospectively in an additional 14 patients, and there was excellent agreement between stroke volumes obtained with thermodilution and scintigraphic methods (r = 0.96, p <O.OOl). In addition, measurements of right ventricular ejection fraction by the equilibrium method agreed closely with those obtained with a gated first pass technique (r = 0.94, p <O.OOl, n = 14). With use of the scintigraphic rlght ventricular ejection fraction and the relation between scintigraphic and thermodilution measurements of right ventricular stroke volume, right ventricular end-diastolic and end-systolic volumes can be estimated. Thus, nongeometric radionuclide techniques may be used for the quantitation of right ventricular volumes.
A century of indicator dilution technique
Clinical Physiology and Functional Imaging, 2014
This review imparts the history and the present status of the indicator dilution technique with quantitative bolus injection. The first report on flow measurement with this technique appeared 100 years ago. In 1928, the use of intravascular dyes made possible a widespread application in animals and human during the next decades. Multiple indicators, radioactive tracers, inlet-outlet detection and residue detection were introduced in the 1950s and 1960s, and refined along with the development of indicator kinetics. From the 1970s, a wide clinical use in the study of heart, brain, lungs, liver and kidneys developed, and powerful computers in the 1980s and 1990s accorded the technique a new dimension. Today, the indicator dilution technique, on one hand, is applied in the same way as 100 years ago, on the other hand it forms the basis of quantitative SPECT, positron emission tomography, and dynamic MR scans. The technique still undergoes refinement and elaboration as a lasting concept with a high potential for further development.
Left ventricular volume determination using Albunex
Journal of The American Society of Echocardiography, 1996
The aim of this study was to assess the ability of intravenous injection of Albunex to improve left ventricular volume determination in patients with various cardiac diseases. It is conceivable that the intravenous injection of microbubbles could improve echocardiographic left ventricular border delineation leading to improved interobserver variability. Echocardiograms were obtained during simultaneous intravenous injection of 0.08 and 0.12 ml/kg Albunex (four-chamber view). Within 6 hours after the recording of the contrast echocardiograms routine left heart angiography was performed. Volumes were measured using the slice method in native and contrast echocardiograms as well as in the angiograms by two independent investigators. The mean dif-ferences of angiographic-native echocardiographic and angiographic-contrast echocardiographie volumes (ml) as well as the calculated ejection fraction and their confidence intervals were tabulated and significance was an ticipated if the confidence interval did not include zero. Significant changes to angiographic values could be observed concerning end-diastolic, echocardiographic, and contrast echocardiographic volumes at end diastole and end systole, while ejection fractions were similar. Differences between observers were significantly smaller in the contrast echocardiographic images than in the native echocardiographic images, k]bunex led to a significantly decreased interobserver variability. (J AM SOC ECHOCARDIOGR 1996;9:1-8.)
Medical & Biological Engineering & Computing, 2011
While several models have proven to result in accurate estimations when measuring cardiac output using indicator dilution, the mono-exponential model has primarily been chosen for deriving coronary blood/plasma volume. In this study, we compared four models to derive coronary plasma volume using indicator dilution; the mono-exponential, power-law, gamma-variate, and local density random walk (LDRW) model. In anesthetized goats (N = 14), we determined the distribution volume of high molecular weight (2,000 kDa) dextrans. A bolus injection (1.0 ml, 0.65 mg/ml) was given intracoronary and coronary venous blood samples were taken every 0.5-1.0 s; outflow curves were analyzed using the four aforementioned models. Measurements were done at baseline and during adenosine infusion. Absolute coronary plasma volume estimates varied by *25% between models, while the relative volume increase during adenosine infusion was similar for all models. The gamma-variate, LDRW, and mono-exponential model resulted in volumes corresponding with literature, whereas the power-model seemed to overestimate the coronary plasma volume. The gammavariate and LDRW model appear to be suitable alternative models to the mono-exponential model to analyze coronary indicator-dilution curves, particularly since these models are minimally influenced by outliers and do not depend on data of the descending slope of the curve only.
Accuracy and precision of angiographic volumetry methods for left and right ventricle
International Journal of Cardiology, 1996
We imaged and quantified 60 ventricle casts (30 LV, 30 RV) to evaluate the accuracy and reliability of angiographic ventricle volumetry. We analyzed the seven biplane methods most frequently used in clinical routine: Arcilla, Arvidsson, Dodge, Ferlinz, Simpson (LV + RV) and Wynne. The ventricle contours were defined by (1) manual drawing on the computer screen, (2) manual drawing using a graphical tablet and (3) automatic contour detection. A high interclass variation in volume accuracy between the different methods was observed (S.D. = 12.7 ml). The volume methods for the LV (mean differences MDLV: [-2.2, +8.5] ml, average MDLv = 1.8 ml) are more accurate than for the RV (MI&: (-11.4, +33.1] ml, average MDav = 12.1 ml). The intrinsic error is about the same for all approaches and is very high: average S.D. = 20 ml, RMS = 185 ml. Manual contour definition results in a volume over-estimation (average MD,,,.,, = +32.8 ml, r = 0.731) compared with automatic contour detection (average MD,,, = +6.2 ml, r = 0.810). LV hypertrophy results in a volume under-estimation of the LV (MDLV = -7 ml) and an overestimation of the RV (MDRv = +6 ml). RV hypertrophy leads to the opposite effect. It was shown that ventricle volmetry and the calculation of derived parameters (ejection fraction) is extremely case dependent and can only be an estimate of the actual value.
Admittance to detect alterations in left ventricular stroke volume
Heart Rhythm, 2014
BACKGROUND Implantable cardioverter-defibrillators monitor intracardiac electrograms (EGMs) to discriminate between ventricular and supraventricular tachycardias. The incidence of inappropriate shocks remains high because of misclassification of the tachycardia in an otherwise hemodynamically stable individual. Coupling EGMs with an assessment of left ventricular (LV) stroke volume (SV) could help in gauging hemodynamics during an arrhythmia and reducing inappropriate shocks.
Critical Care, 2011
Recently, a non-invasive, continuous ventricular stroke volume monitoring system using skin electrodes has been developed. In contrast to impedance-based methods, the new technique (ventricular field recognition) enables measurement of changes in ventricular volume. A prototype using this new method was built (the hemologic cardiac profiler, HCP) and validated against a reference method in a pig model during variations in cardiac output. Methods: In six Dalland pigs, cardiac output was simultaneously measured with the HCP (CO-HCP), and an invasive ultrasonic flow-probe around the ascending aorta (CO-FP). Variations in CO were achieved by change in ventricular loading conditions, cardiac pacing, and dobutamine administration. Data were analysed according to Bland-Altman analysis and Pearson's correlation.