Herz
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Ventricular dysfunction due to an abnormality of the heart which is associated with typical hemodynamic, renal and hormonal reactions, characterizes the clinical syndrome heart failure. The traditional definition of heart failure as the inability to pump an amount of blood sufficient to cover the metabolic needs of the body in the presence of adequate venous return, emphasizes mainly the reduction in cardiac output but not the increase in intracardiac pressures. Pressure or volume overload, decreased contractility, loss of muscle mass or restricted filling represent the most important pathological processes leading to heart failure. ⋯ With increasing derangement of cardiac function, there is recruitment of the compensatory mechanisms: hypertrophy of the cardiac muscle, Frank-Starling mechanism, activation of the sympathetic nervous system, the renin-angiotensin-aldosterone system and the arginine-vasopressin system. The goal is maintenance of adequate blood pressure and cardiac output whereby blood flow is redistributed in favor of the heart and brain and away from the skin, musculature and visceral organs. Activation of the neurohumoral system can lead to excessive vasoconstriction as well as sodium and water retention resulting in an undesired elevation of preload and afterload which, in turn, leads to further worsening of the heart failure.(ABSTRACT TRUNCATED AT 400 WORDS)
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Review Comparative Study
Interruption of the inferior vena cava for prevention of pulmonary embolism: transvenous filter devices.
The availability of a safe, effective, and easily introducible percutaneous vena cava filter is crucial in the management of certain patients with pulmonary embolism. If thrombolytic or anticoagulant therapy for pulmonary embolism is contraindicated or fails, interruption of the inferior vena cava (IVC) blood flow is the logical alternative. Indications for filter insertion include a contraindication to anticoagulation, or recurrent pulmonary embolism despite adequate anticoagulation therapy. ⋯ Despite these problems, IVC filters have been extremely useful in the management of pulmonary embolism among certain subsets of patients. Percutaneously inserted filters have now superseded surgical vena caval interruption in most US centers. Newer filters are currently under development in the US and Europe, and feature improved filtering function, anti-tilt abilities, retrievability, memory wire properties, and improved ease of insertion.
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Pulmonary embolism was first described by Laennec in 1819. After introduction of the Trendelenburg surgical technique, Kirschner, in 1925, performed the first successful embolectomy. In a review of the literature, in 42 patients, survival rate was 45% on use of a modified Trendelenburg method employing cross-clamping of the vena cava. ⋯ If surgery is delayed until vasoactive drugs are no longer effective, an irreversible condition is frequently incurred in spite of operative removal of the obstruction. More favorable results can be achieved when the indication for surgery is based only on the degree of obstruction since, in this case, the condition of shock will not be prolonged and a hemodynamically-stable patient can be subjected to surgery. 3. Thrombolytic treatment
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With color Doppler ultrasonography, since its inception two years ago, through combination of color-coded flow and gray-coded vessel and tissue imaging, a new technique is available with which, based on the information derived from the Doppler principle, characterization is enabled of the direction of blood flow coded in red or blue, the velocity in varying color intensities and turbulent flow through color mixing. For determination of the velocity of flow at any point in the vessel, additionally, the pulsed Doppler method is available. The diagnosis of obstruction is based on delineation of plaques in the vascular lumen as well as changes in profile of the flowing blood. ⋯ Additionally, information can be obtained with regard to the proximal and distal anastomoses, flow patterns in the region of preserve venous valves, stenoses and arterio-venous fistulas. Pseudoaneurysms are seen as cavity-like perivascular structures devoid of echo signals, the contiguous access to the lumen of which can be verified by display of pulsatile, systolic-diastolic flow in the color-coded image. With color Doppler ultrasonography abnormal flow patterns incurred through atherosclerotic changes in the vessel wall, stenoses, anastomoses, aneurysms and pseudoaneurysms can be reliably detected.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
[Enoximone, a new phosphodiesterase inhibitor: the spectrum of applications during heart surgery--a comparison with dobutamine].
During cardiac surgery treatment of deterioration of myocardial function is usually based on catecholamines. Development of selective phosphodiesterase-(PDE-)III-inhibitors seems to be a new aspect in treating myocardial dysfunction. Therefore the hemodynamic effects of the new PDE-inhibitor enoximone were investigated in 20 coronary surgery patients unable to be weaned from extracorporeal circulation (ECC) without pharmacological intervention (MAP less than 60 mmHg, CI less than 2.00 l/min.m2, PCP greater than 15 mmHg). ⋯ Ten minutes after weaning from ECC additional pharmacologic therapy (calcium, vasodilators, epinephrine) was necessary in eight dobutamine treated patients in contrast to four patients in the enoximone group (calcium, epinephrine). In patients with impaired myocardial performance during weaning from ECC enoximone seems to be an alternative therapy and is judged to be of some advantage compared to dobutamine application in this situation. The mechanism for improvement appears to be enhanced contractility owing to its positive inotropic effects, as well as a decrease in left ventricular outflow resistance resulting from peripheral vasodilation.