Herz
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The ultimate goal of any imaging technique for the investigation of the anatomy of the beating heart is a 3D-display of the cardiac morphology throughout a complete heart cycle. The reason for this interest is quite clear: 3D-imaging has the potential for a better understanding of the individual morphology under normal and pathological conditions and especially, if complex therapeutic decisions have to been made. In the clinical practice, the echocardiographer attempts to obtain a spatial information by a mental reassembling of the 2D echocardiographic images, that are obtained from different imaging planes. ⋯ The process of 3D-reconstruction is a sequence of repeated steps of image processing. The first step is the elimination of a problem, that is common to all image reconstruction techniques from tomographic information: the imaging planes are recorded at different time points, and mostly under varying conditions. Although several gating techniques are implemented into the image acquisition, some variability is unavoidable, simply because neither the heart nor the surroundings can be frozen during image acquisition.(ABSTRACT TRUNCATED AT 400 WORDS)
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The extent of myocardial damage occurring during acute myocardial infarction is time dependent, and there is abundant evidence from most clinical trials that mortality reduction is greatest in patients treated early with thrombolytic agents, although beneficial effects have been shown with treatment initiated up to 12 hours after onset of symptoms. This temporal dependence of benefit was most clearly seen with the 47% mortality reduction obtained with streptokinase given within the first hour in the GISSI-1 trial (Table 1). The process of infarction may be completely aborted if reperfusion is initiated within 30 minutes after symptom onset. ⋯ The paramedics then obtained a computer-interpreted ECG which was transmitted to the emergency department in the hospital where a physician made the decision on the form of treatment. The thrombolytic agent was then administered by the paramedic. In the European Myocardial Infarction Project (EMIP) an emergency physician was personally present and responsible in the prehospital setting, whereas in the Grampian Region Early Anistreplase Trial (GREAT) general practitioners made the decision for enrolling the patient.
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Cardiogenic shock in acute myocardial infarction patients is the most common cause of in-hospital death. Various studies showed, that 60 to 100% of patients in cardiogenic shock will die, if no early reperfusion of their coronary artery could be established. The incidence of cardiogenic shock has decreased during the last years, most likely due to early thrombolytic therapy and administration of nitroglycerin. ⋯ Results of early surgery in papillary muscle rupture or ventricular septal defects are much better than delayed interventions. Rupture of the free wall is usually a fatal event. In summary, the most successful therapy of cardiogenic shock is early emergency PTCA.(ABSTRACT TRUNCATED AT 400 WORDS)
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Both the hibernating and the stunned myocardium are characterized by reversible contractile dysfunction. In hibernating myocardium ischemia is still ongoing, whereas in stunned myocardium blood flow is fully or almost fully restored. Both the hibernating and the stunned myocardium retain an inotropic reserve. ⋯ Myocardial stunning per se requires no therapy at all, since by definition blood flow is normal and contractile function will recover spontaneously. If, however, myocardial stunning involves large parts of the left ventricle and thus impairs global left ventricular function, the extent of myocardial stunning can be reduced by inotropic stimulation, without inducing further damage to the myocardium. In the experimental setting, antioxidant agents, calcium antagonists and ACE inhibitors attenuate stunning, most effectively when administered before ischemia.
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Transesophageal echocardiography is an important diagnostic tool available to the critical care physician. Indications for the use of transesophageal echocardiography in the intensive care unite include: critical illness and circulatory shock, thoracic aortic dissection, pulmonary embolism and endocarditis. Probe insertion is easy and is successful in 98% of intensive care patients. ⋯ Right ventricular infarction: The transgastric view is usefull in detecting right ventricular wall motion abnormalities and dilatation. Hemodynamically significant right ventricular infarction occurs in the posterior wall, which makes the transesophageal approach ideal. We studied a group of 39 patients with right ventricular infarction.(ABSTRACT TRUNCATED AT 400 WORDS)