Relationship of echocardiographic indices to pulmonary capillary wedge pressures in healthy volunteers.
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OBJECTIVES: We sought to determine the relationship between different echocardiographic indices and pulmonary capillary wedge pressures (PCWP) in normal volunteers. BACKGROUND: Indices based on tissue Doppler (TDE) and color M-mode (CMM) echocardiography have been proposed to reflect left (LV) ventricular filling pressures. These include the ratio of early diastolic transmitral velocity (E) to early myocardial velocity measured by TDE (E') and the ratio of E to the wave propagation velocity (Vp) measured from CMM images. These indices, however, have not been validated in normal individuals. METHODS: We studied seven volunteers during two phases of preload altering maneuvers, baseline, with two stages of lower body negative pressure, and repeat baseline with two stages of volume loading. The PCWP obtained from right heart catheterization was compared with diastolic indices using pulsed Doppler, TDE and CMM echocardiography. RESULTS: The PCWP ranged from 2.2 to 23.5 mm Hg. During preload alterations, significant changes in E and septal E' (both p < 0.05) but not lateral E' or Vp were observed. Furthermore, E, septal E' and E/Vp correlated with PCWP (all r > 0.80) but not combined E and TDE indices (both r < 0.15). Within individuals, a similar linear relationship was observed among E/Vp, E and septal E' (average r > 0.80). CONCLUSIONS: In subjects without heart disease, E, septal E' and E/Vp correlate with PCWP. Because the influence of ventricular relaxation is minimized, the ratio E/Vp may be the best overall index of LV filling pressures. (+info)
Cardiac exercise hemodynamics late after partial left ventriculectomy.
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BACKGROUND: Although some patients report favorable activity levels late after partial left ventriculectomy (PLV), their exercise physiology has not been well described. METHODS AND RESULTS: We performed upright bicycle hemodynamics in 10 patients (9 men) aged 56+/-12 years at 1.7 years after PLV. Ejection fraction was 25+/-4%. Patients biked 10+/-7 minutes. With exercise, the mean pulmonary arterial pressure rose from 36+/-12 to 52+/-10 mm Hg (P:=0.0003). The mean pulmonary capillary wedge pressure rose from 25+/-14 to 36+/-9 mm Hg (P:=0.0566), and the cardiac index rose from 2.2+/-0.5 to 3.8+/-1.6 L. min(-1). m(-2) (P:=0.0077). The mixed venous oxygenation with exercise declined from 44+/-9% to 24+/-17% (P:=0. 0220), and the pulmonary vascular resistance increased from 2.0+/-0. 9 to 2.3+/-1.1 Wood units (P:=0.5566). CONCLUSIONS: In late follow-up after PLV with exercise, the cardiac index is significantly augmented. However, there are further rises in pulmonary artery and pulmonary capillary wedge pressures, suggesting abnormal compliance, with marked decline in mixed venous oxygenation. Elucidating late physiology after PLV may help pave the way for future innovative heart failure surgeries. (+info)
Hemoglobin and red blood cells alter the response of expired nitric oxide to mechanical forces.
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Expired nitric oxide (NO(e)) varies with hemodynamic or ventilatory perturbations, possibly due to shear stress- or stretch-stimulated NO production. Since hemoglobin (Hb) binds NO, NO(e) changes may reflect changes in blood volume and flow. To determine the role of blood and mechanical forces, we measured NO(e) in anesthetized rabbits, as well as rabbit lungs perfused with buffer, red blood cells (RBCs) or Hb following changes in flow, venous pressure (P(v)), and positive end-expiratory pressure (PEEP). In buffer-perfused lungs decreases in flow and P(v) reduced NO(e), but NO(e) rose when RBCs and Hb were present. These findings are consistent with changes in vascular NO production, whose detection is obscured in blood-perfused lungs by the more dominant effect of Hb NO scavenging. PEEP decreased NO(e) in all perfused lungs but increased NO(e) in live rabbits. The NO(e) fall with PEEP in isolated lungs is consistent with flow redistribution from alveolar septal capillaries to extra-alveolar vessels and decreased surface area or a direct, stretch-mediated depression of lung epithelial NO production. In live rabbits, increased NO(e) may reflect blood flow reduction and decreased Hb NO scavenging and/or autonomic responses that increase NO production. We conclude that blood and systemic responses render it difficult to use NO(e) changes as an accurate measure of lung tissue NO production. (+info)
Using heart-lung interactions to assess fluid responsiveness during mechanical ventilation.
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According to the Frank-Starling relationship, a patient is a 'responder' to volume expansion only if both ventricles are preload dependent. Mechanical ventilation induces cyclic changes in left ventricular (LV) stroke volume, which are mainly related to the expiratory decrease in LV preload due to the inspiratory decrease in right ventricular (RV) filling and ejection. In the present review, we detail the mechanisms by which mechanical ventilation should result in greater cyclic changes in LV stroke volume when both ventricles are 'preload dependent'. We also address recent clinical data demonstrating that respiratory changes in arterial pulse (or systolic) pressure and in Doppler aortic velocity (as surrogates of respiratory changes in LV stroke volume) can be used to detect biventricular preload dependence, and hence fluid responsiveness in critically ill patients. (+info)
Predictors of disease course in patients with acute myocarditis.
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BACKGROUND: Clinical manifestations of acute myocarditis, with distinct onset, vary from asymptomatic to fatal. The predictors of the course of the disease in patients with acute myocarditis at initial presentation have not yet been established. In this study, we examined the predictive values of various parameters in the disease course of patients with myocarditis. METHODS AND RESULTS: Twenty-one consecutive patients who had been diagnosed as having acute myocarditis by histological examinations were analyzed. The patients with myocarditis were divided into the survival group (n=13) and the fatal group (n=8). We examined the parameters of the clinical state, hemodynamic variables, required therapies, biochemical laboratory data, and cytokines. The control groups were composed of 23 patients with old myocardial infarction and 20 healthy volunteers. The fatal group had lower blood pressure and higher pulmonary capillary wedge pressure compared with those values in the survival group. Mechanical ventilation support was more frequently required in the fatal group. Serum levels of soluble Fas (sFas) and soluble Fas ligand (sFasL) were significantly higher in the myocarditis group than in the 2 control groups. Furthermore, levels were significantly higher in the fatal group than in the survival group for sFas (13.93+/-4.77 versus 3.77+/-0.52 ng/mL, respectively; P:<0.001) and sFasL (611.4+/-127.7 versus 269.5+/-37.3 pg/mL, respectively; P:<0.05). Other clinical states, hemodynamic variables, required therapies, and biochemical laboratory parameters were not different between the 2 groups. CONCLUSIONS: Elevation of sFas and sFasL levels at initial presentation appear to be a good serological marker to predict the prognosis of acute myocarditis. (+info)
Independent and additive prognostic value of right ventricular systolic function and pulmonary artery pressure in patients with chronic heart failure.
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OBJECTIVES: We sought a better understanding of the coupling between right ventricular ejection fraction (RVEF) and pulmonary artery pressure (PAP), as it might improve the accuracy of the prognostic stratification of patients with heart failure. BACKGROUND: Despite the long-standing view that systolic function of the right ventricle (RV) is almost exclusively dependent on the afterload that this cardiac chamber must confront, recent studies claim that RV function is an independent prognostic factor in patients with chronic heart failure. METHODS: Right heart catheterization was performed in 377 consecutive patients with heart failure. RESULTS: During a median follow-up period of 17 +/- 9 months, 105 patients died and 35 underwent urgent heart transplantation. Pulmonary artery pressure and thermodilution-derived RVEF were inversely related (r = 0.66, p < 0.001). However, on Cox multivariate survival analysis, no interaction between such variables was found, and both turned out to be independent prognostic predictors (p < 0.001). It was found that RVEF was preserved in some patients with pulmonary hypertension, and that the prognosis of these patients was similar to that of the patients with normal PAP. In contrast, when PAP was normal, reduced RV function did not carry an additional risk. CONCLUSIONS: These observations emphasize the necessity of combining the right heart hemodynamic variables with a functional evaluation of the RV when trying to define the individual risk of patients with heart failure. (+info)
Estimating pulmonary capillary wedge pressures using Doppler variables of early diastolic left ventricular inflow.
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The present study was performed to determine whether a multilineal regression model based on the early diastolic transmitral flow peak velocity (E) and the propagation velocity of early diastolic inflow (PV) could estimate the pulmonary capillary wedge pressure (PCWP). PCWP and Doppler variables were simultaneously recorded in 30 patients. PCWP was estimated by multilinear regression analysis using E and PV. The predictive accuracy of the equation obtained from the analysis was tested prospectively in a separate group of 65 patients divided into 3 groups: left ventricular (LV) systolic dysfunction (Group A), LV hypertrophy (Group B), and preserved systolic function without hypertrophy (Group C). The initial results obtained in groups B and C, respectively, were: r=0.77; r=0.81. These results indicate that a multilinear regression model based on E and PV is a noninvasive method of accurately estimating PCWP in a variety of cardiac disease states. (+info)
Hemodynamic effects of tezosentan, an intravenous dual endothelin receptor antagonist, in patients with class III to IV congestive heart failure.
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BACKGROUND: Endothelin-1, a powerful mediator of vasoconstriction, is increased in patients with congestive heart failure and appears to be a prognostic marker that strongly is correlated with the severity of disease. However, little is known about the potential immediate beneficial effects of acute blockade of the endothelin system in patients with symptomatic left ventricular dysfunction. We assessed the hemodynamic effects and safety of tezosentan, an intravenous dual endothelin receptor antagonist, in patients with moderate to severe heart failure. METHODS AND RESULTS: This randomized placebo-controlled study evaluated the hemodynamic effects of 6-hour infusions of tezosentan at 5, 20, 50, and 100 mg/h compared with placebo in 61 patients with New York Heart Association class III to IV heart failure. Plasma endothelin-1 and tezosentan concentrations were also determined. Treatment with tezosentan caused a dose-dependent increase in cardiac index ranging from 24.4% to 49.9% versus 3.0% with placebo. Tezosentan also dose-dependently reduced pulmonary capillary wedge pressure and pulmonary and systemic vascular resistances, with no change in heart rate. No episodes of ventricular tachycardia or hypotension requiring drug termination were observed during tezosentan infusion. Tezosentan administration resulted in dose-related increased plasma endothelin-1 concentrations. CONCLUSIONS: The present study demonstrated that tezosentan can be safely administered to patients with moderate to severe heart failure and that by virtue of its ability to antagonize the effects of endothelin-1, it induced vasodilatory responses leading to a significant improvement in cardiac index. Further studies are under way to determine the clinical effects of tezosentan in the setting of acute heart failure. (+info)