Herz
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Impaired diastolic function of the hypertrophied and stiffened left ventricle is a characteristic feature of hypertrophic cardiomyopathy (Figure 1). Altered left ventricular filling dynamics and reduced left ventricular distensibility or increased left ventricular diastolic chamber stiffness are associated with reduced left ventricular stroke volume, increased left ventricular filling pressures and compressive effects on the coronary microcirculation. These factors contribute importantly to the clinical presentation of many patients, including symptoms of fatigue, dyspnea and angina pectoris. ⋯ Other factors are nonuniform and asynchronous regional ventricular function due to differing increases in thickness of the ventricular walls and ischemia (Figure 4). Calcium channel blockers exert a favorable influence on left ventricular relaxation and filling (Figure 5); verapamil and diltiazem are preferable to nifedipine. Verapamil increases left ventricular stroke volume without an increase in the end-diastolic pressure (Figure 6), reduces regional asynchrony if present, and leads to a more homogeneous regional diastolic filling (Figure 4).(ABSTRACT TRUNCATED AT 250 WORDS)
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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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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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Oral contraceptives represent the most commonly employed means of contraception in the Federal Republic; they are used in 25% of all women in child-bearing age. The risk of myocardial infarction or cardiovascular death while taking oral contraceptives is determined primarily by three factors: the age of the user, the type and concentrations of estrogen and gestagen administered as well as the concomitant risk factors for coronary artery disease. With currently-used low-dose hormonal contraceptives, in young women (less than 30 years of age) who do not smoke and do not have other risk factors for coronary artery disease, there is no clear increase in the normally low risk of developing coronary artery disease or myocardial infarction. ⋯ The relevance of the duration of oral contraceptive use on the risk of infarction remains controversial. The number of young women with myocardial infarction and no or single-vessel coronary artery disease is significantly higher at 60% in women who have used oral contraceptives than in women of comparable age without oral contraceptive use (30%). The pathophysiological mechanism primarily responsible for myocardial infarction in oral contraceptive users and smokers appears to be thrombosis.