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Kawai A - - 1994
To evaluate the efficacy of University of Wisconsin solution for clinical heart transplantation, load-independent parameters were used to assess left ventricular function after transplantation. Donor hearts were arrested with and stored in buffered cold cardioplegic solution for control (n = 5) and University of Wisconsin solution for the experimental group ...
Nakatani S - - 1994
Diastolic suction has been demonstrated experimentally as a ventricular negative pressure when the ventricle is allowed to relax completely in the absence of filling, but it has not been extensively studied in the in vivo human heart. In balloon mitral valvuloplasty with a single balloon, the mitral orifice is occluded ...
Naganuma F - - 1994
To clarify how angiotensin converting enzyme inhibition affects left ventricular function through ventricular unloading, ventricular wall stress, ventricular volumes, and other cardiac indices and exercise tolerance were evaluated in 17 patients with mild to moderate chronic congestive heart failure before and after 3 months of treatment with enalapril. Echocardiographic examination ...
Meyer T E - - 1993
Although end-systolic pressure length and thickness relationships (ESPLR, ESPTR) are now widely used as substitutes for the end-systolic pressure volume relationships, there are some reservations about their use as an index of left ventricular (LV) performance. This study addressed three issues, namely: (1) which loading technique (decreasing preload by inferior ...
Park S E - - 1993
We hypothesized that the right latissimus dorsi cardiomyoplasty augments left ventricular performance. Five dogs underwent staged right latissimus dorsi cardiomyoplasty. Ventricular function was studied 1 to 3 weeks later. Left ventricular pressure was measured with a micromanometer and left ventricular dimensions with piezoelectric crystals. Inferior vena caval occlusion was used ...
Krams R - - 1993
Regional end-systolic pressure-segment length relationships (ESPSLR) were used to compare the degree of right and left ventricular stunning induced by a 10-min occlusion of the left anterior descending coronary artery and the response to subsequent atrial pacing (50 beats/min above intrinsic heart rate) without and with dobutamine (2 micrograms.kg-1.min-1) in ...
Erbas T - - 1993
Since somatostatin has been reported to have a negative inotropic and chronotropic effect on atria and positive inotropic effect on ventricle, present study was designed to investigate the acute effects of somatostatin analogue SMS 201-995 infusion on the left ventricular function in healthy volunteers. After labeling the autologous red blood ...
Schipper I B - - 1993
It has been shown that in the intact canine heart the left-ventricular end-systolic pressure/volume relation (ESPVR) depends on loading conditions: an increase in arterial vascular resistance causes a leftwards shift and a steeper slope of the ESPVR, suggesting an increased inotropic state. Our purpose was to investigate the possible contribution ...
Pagel P S - - 1993
Development of an index of myocardial contractility that is load independent and that can be derived from a single cardiac cycle in vivo has important intraoperative ramifications. Recently, a new index of contractile state based on maximal ventricular power (the rate of ventricular work) has been proposed that appears to ...
Vanoverschelde J L - - 1993
The relationship of myocardial O2 consumption (MVO2) to its potential hemodynamic and mechanical determinants was investigated in eight healthy normal volunteers at rest and during infusion of dobutamine (5-10 micrograms.kg-1.min-1). MVO2 was calculated from the monoexponential myocardial clearance of [1-11C]acetate with positron emission tomography, and left ventricular mechanical function was ...
Beyar R - - 1993
OBJECTIVE: The aim was to study the effects of the collagen mesh that interconnects the myocardial fibres on left ventricular mechanics and intramyocardial pressure. METHODS: An earlier model which integrates a symmetrical left ventricular geometry and transmural muscle fibre structure with muscle fibre mechanics was expanded to include radial stiffness ...
Huber T S - - 1993
OBJECTIVE: To test the hypothesis that the induction and maintenance of brain death leads to a decrease in myocardial contractility. DESIGN: Prospective, randomized, controlled trial. SETTING: Laboratory at a large, university-affiliated medical center. SUBJECTS: Sixteen adult, male, mongrel dogs weighing 15 to 25 kg. INTERVENTIONS: Myocardial contractile performance was evaluated ...
Peterseim D S - - 1993
The occurrence of brain death has been shown to significantly diminish left ventricular function in the adult porcine model. This study examined whether the pediatric myocardium is as sensitive as the adult myocardium to the detrimental effects of brain death in the porcine model. Left ventricular intracavitary pressure and major ...
Her C - - 1993
OBJECTIVE: Since right ventricular ejection fraction is highly dependent on afterload, right ventricular ejection fraction may not reflect right ventricular contractile function in acute respiratory failure. Despite a severe reduction in right ventricular ejection fraction, the right ventricle may be able to generate pressure output that is sufficient enough to ...
Magovern J A - - 1993
BACKGROUND: We hypothesized that left ventricular function could be improved with cardiomyoplasty using the right latissimus dorsi. METHODS AND RESULTS: Five dogs underwent cardiomyoplasty using the right latissimus dorsi. Left ventricular volume and pressure were measured using sonomicrometry and a micromanometer catheter, respectively. Pressure volume loops were recorded with the ...
Liu C P - - 1993
BACKGROUND: Experimental studies indicate that in addition to diastolic dysfunction, hypertrophied myocardium can display depressed contractile responses, particularly at rapid heart rates, compounding reserve limitations. This study tests whether such abnormalities exist in intact human subjects at physiological paced rates and, if so, whether they are linked to simultaneous rate-dependent ...
Hexeberg E - - 1993
Previous studies have shown that the combined increase of preload and afterload leads to a more uniform wall contraction. As our previous information with a stable afterloaded situation showed considerable increase of left ventricular end-diastolic pressure, we have as yet no information of how afterload per se effects uniformity of ...
Kim H C - - 1993
An adaptive algorithm to detect full ejection points was developed for the automatic control of the electrohydraulic total artificial heart (EHTAH). To automatically control the EHTAH, systole in each ventricle is completed when a hyper-pressurization spike is detected on the oil side of that ventricle. A problem associated with the ...
Prabhu S D - - 1993
Studies of ventricular energetics using the relation between myocardial O2 consumption (MVO2) and pressure-volume area (PVA) have been performed extensively in the isolated heart, but not in the intact animal. We characterized the MVO2-PVA relation and its response to heart rate (HR) in eight closed-chest dogs instrumented with high-fidelity micromanometers, ...
Pelster B - - 1993
The influence of acetylcholine (ACh) on cardiac performance of larval (Taylor Kollros [TK] stages II-XVIII) and postmetamorphic (3-609 g) Rana catesbeiana was analyzed in situ (circulatory system intact) and in vitro (isolated heart or ventricular strip preparations). Topical application of ACh to the heart in situ resulted in a dose-dependent ...
Murphy C F - - 1993
OBJECTIVE: The aim was to investigate the behaviour of regional myocardium during mechanical alternans in a multidirectional manner. METHODS: Mechanical alternans was induced in 12 anaesthetised open chested pigs by rapid atrial pacing. In contrast to previous studies, regional mechanical activity was simultaneously assessed at up to three different sites ...
Yaku H - - 1993
The purpose of the present study was to evaluate the feasibility of partitioning myocardial O2 consumption (VO2) into mechanical and nonmechanical components in the whole heart preparation using a negative inotrope, 2,3-butanedione monoxime (BDM), which has been reported to have a selective effect on the contractile proteins in a low ...
Fuenmayor A J - - 1993
We studied eight patients to determine whether changes occur in the QRS amplitude when these patients are submitted to hemodialysis. The following variables were assessed before and after each (N = 28) hemodialysis session: (1) plasma sodium and potassium concentrations, (2) QRS amplitude, (3) the heart rate and its variability, ...
Kusuoka H - - 1993
Contractile function of the left ventricle is often measured regionally, particularly in intact animals. In this paper I dispute the validity of the common assumption that regional shortening accurately reflects whole-heart mechanics, even when contractility is homogeneous, by using an ellipsoidal model of the left ventricle to examine the relationship ...
Burkhoff D - - 1993
This study focuses on elucidating how ventricular afterloading conditions affect the time course of change of left ventricular pressure (LVP) throughout the cardiac cycle, with particular emphasis on revealing specific limitations in the time-varying elastance model of ventricular dynamics. Studies were performed in eight isolated canine hearts ejecting into a ...
Kawaguchi O - - 1993
We studied the effects of ejection velocity and resistive properties of the left ventricle (LV) on myocardial oxygen consumption (VO2) in 13 excised cross-circulated dog hearts. Increases in peak ejection velocity (-dV/dt) from 4.0 +/- 1.3 (SD) end-diastolic volume (EDV)/s to 12.7 +/- 5.3 EDV/s with constant EDV and end-systolic ...
Holmes J W - - 1993
Aerodynamic tests are designed to give information about the performance of a model when subjected to an airflow. The introduction of pressure sensitive paint provides a new method for obtaining the pressure distribution on the surface of wind-tunnel models. A paint, the luminescence of which is dependent on air pressure, ...
Dahlgren G - - 1993
Transthoracic two-dimensional echocardiography was used to measure left ventricular diameter in end-systole and end-diastole during anesthetic induction in 11 patients before coronary artery bypass grafting. Midazolam, 0.1 mg/kg, and fentanyl, 6 to 10 micrograms/kg, were used followed by pancuronium, 0.1 mg/kg. Lidocaine, 1.5 mg/kg, was given topically in the airways ...
Chirife R - - 1993
Ejection fraction (EF), the ratio between stroke volume (SV) and end-diastolic volume (EDV), is a valuable contractility indicator. Unlike SV, the Frank-Starling effect is automatically compensated in the calculation of EF. It was the aim of this study to evaluate the physiological behavior of impedance derived measurements of relative right ...
Adler D - - 1993
A comprehensive discrete analysis of the hemodynamic variables during sustained mechanical alternans (SMA) shows that these variables are governed by simple mathematical relations. The analysis shows that the value of the slope created by the two alternating beats on the stroke volume-end diastolic (SV-EDV) plane is gamma = (mu - ...
Cho P W - - 1993
Reports of clinical improvement in human studies of dynamic cardiomyoplasty lack support by consistent objective hemodynamic evidence. Animal studies have also yielded conflicting results, likely due to nonuniform models, particularly the use of unconditioned wraps, and to limitations in commonly used study modalities caused by exaggerated heart motion during wrap ...
Shoucri R M - - 1993
This study presents new mathematical relations to link oxygen consumption to different areas under the end-systolic pressure-volume relation (ESPVR). The approach consists of approximating the relation between oxygen consumption and left ventricular pressure by a quadratic polynomial, and then relating the coefficients of the quadratic polynomial to different areas under ...
Dávila-Román V G - - 1993
Analysis of the pressure-dimension relationship provides a sensitive index of myocardial contractility, but widespread application of this method is limited because it requires invasive measurement techniques. The recent development of two-dimensional echocardiographic automatic boundary detection permits accurate and reproducible on-line measurement of ventricular cavity areas that can be combined with ...
Reich D L - - 1993
BACKGROUND: Intraoperative blood volume changes are difficult to monitor in pediatric patients. The authors tested the hypothesis that transesophageal echocardiography would identify changes in cardiac filling resulting from manipulations of blood volume. METHODS: Eleven patients (3-15 kg) were studied following sternal closure after repair of congenital heart lesions. Transesophageal echocardiography ...
Andoh T - - 1993
It has been reported that continuous negative extrathoracic pressure ventilation (CNETPV) depresses cardiac output less than continuous positive pressure ventilation (CPPV) does, and this difference may be related to the different effects of two ventilatory modes on preload. We performed simultaneous measurements of hemodynamics and left ventricular short axis dimensions ...
Ko W - - 1993
The effects on the postischemic myocardium of amrinone and dobutamine were studied in canine hearts that underwent 90 minutes of hypothermic (10 degrees C) arrested ischemia. In an isolated heart preparation cross-circulated by a support dog, left ventricular pressure-volume loops were collected under a constant afterload based on a mock ...
De Tombe P P - - 1993
Recent clinical and animal studies have suggested that ventricular-vascular coupling normally operates at either optimal ventricular efficiency (EFF = stroke work/myocardial oxygen consumption) or stroke work (SW) and that efficiency in particular is compromised by cardiac dysfunction. These distinctions between coupling states at maximal work vs. efficiency are largely based ...
Shintani H - - 1993
BACKGROUND: The importance of the mitral apparatus to left ventricular function has been suggested in clinical studies. The effect of disruption of the mitral apparatus on left ventricular diastolic and systolic properties has not been fully documented. METHODS AND RESULTS: We investigated the end-diastolic and end-systolic pressure-volume and stroke work-end-diastolic ...
Mols P - - 1993
The effects of aminophylline on pulmonary vascular tone, systemic hemodynamics, and ventricular ejection fractions reported in the literature show some discrepancies. We therefore studied in COPD patients the effects of aminophylline on hemodynamics, on ventricular ejection fractions, and on systolic and diastolic functions of each ventricle, and we measured simultaneously ...
Patel R - - 1993
We prospectively compared auscultatory findings of third heart sounds with radionuclide ventriculographic analysis of systolic and diastolic function. Cardiac auscultation was done to detect an S3 in patients referred for radionuclide ventriculographic analysis of ventricular function. Of 49 adult men with the diagnosis of chronic, nonvalvular heart failure who were ...
Porembka D T - - 1993
The cardiovascular response in sepsis is the result of subcellular dysfunction and impaired metabolism from the complex interaction of cytokine and mediator with cellular involvement. The typical cardiovascular abnormalities seen are tachycardia, hypotension (relative decrease in preload), increased cardiac index, decrease in left ventricular stroke work index, decrease in ejection ...
Krams R - - 1993
OBJECTIVE: In order to determine whether the relatively high oxygen consumption of stunned myocardium is related to decreased mechanical efficiency, myocardial oxygen consumption (MVO2) and its major determinants were studied in 10 open chest anaesthetised pigs. METHODS: According to the time varying elastance concept, MVO2 is determined by contractility (Emax) ...
Nakamoto T - - 1993
OBJECTIVE: The aim was to determine the slope (EES) of the left ventricular end systolic pressure-volume line (ESPVL) without altering preload or afterload in conscious dogs. METHODS: Dogs (n = 10) were instrumented to determine left ventricular volume from ultrasonic left ventricular internal dimensions, and to measure left ventricular pressure ...
Tsutsui H - - 1993
Cardiac hypertrophy in response to systolic pressure loading frequently results in contractile dysfunction of unknown cause. In the present study, pressure loading increased the microtubule component of the cardiac muscle cell cytoskeleton, which was responsible for the cellular contractile dysfunction observed. The linked microtubule and contractile abnormalities were persistent and ...
Delhaas T - - 1993
To determine the relation between regional electrical activation time and fiber strain, epicardial electrical activation and deformation were measured in six open-chest dogs at the left ventricular anterior free wall after 15 min of right atrial, left ventricular free wall, left ventricular apex, or right ventricular outflow tract pacing, when ...
Abrams J H - - 1993
Ventricular pressure-volume (PV) loops provide information about ventricular function. Methodologic constraints have limited derivation of PV loops to the laboratory. The present study addresses derivation of PV loops from a direct left ventricular pressure measurement and left ventricular volume derived from continuous cardiac output. The measurements were performed in vivo ...
Ilia R - - 1993
Left ventricular end-diastolic pressure at rest, left ventricular ejection fraction, thallium segmental abnormalities, as well as sex, age and presence of diabetes mellitus, hypertension, hypercholesterolemia and smoking excess were analyzed in 40 patients with abnormal thallium stress test and normal coronary angiograms. Of these patients, 25 had elevated left ventricular ...
Wisenbaugh T - - 1993
OBJECTIVES: This study examined the long-term (3-month) effects of nebivolol, a new beta-adrenergic blocking agent, on cardiac performance in patients with dilated cardiomyopathy. BACKGROUND: Several beta-blocking drugs have been reported to have a beneficial hemodynamic effect in patients with dilated cardiomyopathy, but few data obtained in a placebo-controlled randomized study ...
Nevo E - - 1993
Optimal ventriculoarterial coupling, in terms of maximal energetic efficiency, was recently analyzed by analytic and experimental studies. Whereas for normal hearts the analytic predictions agreed well with measured data, failing hearts were found to operate remote from the predicted optimal conditions. An analysis of optimal coupling is developed in the ...
Gratama J W - - 1993
To determine how much myocardial O2 consumption (VO2) would increase during an additional load on the heart in shunt as compared with control lambs, we studied 12 7-wk-old lambs with an aortopulmonary left-to-right shunt (59 +/- 3% of left ventricular output, mean +/- SE) and 11 control lambs during exercise ...
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