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      Ventricular remodeling after myocardial infarction. Experimental observations and clinical implications.

      1 , 1

      Circulation

      Ovid Technologies (Wolters Kluwer Health)

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          Abstract

          An acute myocardial infarction, particularly one that is large and transmural, can produce alterations in the topography of both the infarcted and noninfarcted regions of the ventricle. This remodeling can importantly affect the function of the ventricle and the prognosis for survival. In the early period, infarct expansion has been recognized by echocardiography as a lengthening of the noncontractile region. The noninfarcted region also undergoes an important lengthening that is consistent with a secondary volume-overload hypertrophy and that can be progressive. The extent of ventricular enlargement after infarction is related to the magnitude of the initial damage to the myocardium and, although an increase in cavity size tends to restore stroke volume despite a persistently depressed ejection fraction, ventricular dilation has been associated with a reduction in survival. The process of ventricular enlargement can be influenced by three interdependent factors, that is, infarct size, infarct healing, and ventricular wall stresses. A most effective way to prevent or minimize the increase in ventricular size after infarction and the consequent adverse effect on prognosis is to limit the initial insult. Acute reperfusion therapy has been consistently shown to result in a reduction in ventricular volume. The reestablishment of blood flow to the infarcted region, even beyond the time frame for myocyte salvage, has beneficial effects in attenuating ventricular enlargement. The process of scarification can be interfered with during the acute infarct period by the administration of glucocorticosteroids and nonsteroidal antiinflammatory agents, which result in thinner infarcts and greater degrees of infarct expansion. Modification of distending or deforming forces can importantly influence ventricular enlargement. Even short-term augmentations in afterload have deleterious long-term effects on ventricular topography. Conversely, judicious use of nitroglycerin seems to be associated with an attenuation of infarct expansion and long-term improvement in clinical outcome. Long-term therapy with an angiotensin converting enzyme inhibitor can favorably alter the loading conditions on the left ventricle and reduce progressive ventricular enlargement as demonstrated in both experimental and clinical studies. With the former therapy, this attenuation of ventricular enlargement was associated with a prolongation in survival. The long-term clinical consequences of long-term angiotensin converting enzyme inhibitor therapy after myocardial infarction is currently being evaluated. Although studies directed at attenuating left ventricular remodeling after infarction are in the early stages, it does seem that this will be an important area in which future research might improve long-term outcome after infarction.

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          Most cited references 54

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          Effect of captopril on progressive ventricular dilatation after anterior myocardial infarction.

          We conducted a double-blind, placebo-controlled trial to determine whether ventricular dilatation continues during the late convalescent phase after myocardial infarction and whether therapy with captopril alters this process. Fifty-nine patients with a first anterior myocardial infarction and a radionuclide ejection fraction of 45 percent or less underwent cardiac catheterization 11 to 31 days after infarction, when they were not in overt congestive heart failure. They were randomly assigned to placebo or captopril and were followed for one year. A repeat catheterization was performed to evaluate interval changes in hemodynamic function and left ventricular volume. Thirty-eight male patients were evaluated with maximal-exercise treadmill tests every three months. No differences were detected at base line in clinical, hemodynamic, or quantitative ventriculographic variables. During one year of follow-up, the end-diastolic volume of the left ventricle increased by a mean [+/- SEM] of 21 +/- 8 ml (P less than 0.02) in the placebo group, but by only 10 +/- 6 ml (P not significant) in the captopril group. The left ventricular filling pressure remained elevated with placebo but decreased (P less than 0.01) with captopril. In a subset of 36 patients who were at high risk for ventricular enlargement because they had persistent occlusion of the left anterior descending coronary artery, captopril prevented further ventricular dilatation (P less than 0.05). Patients given captopril also had increased exercise capacity (P less than 0.05). This preliminary study indicates that after anterior myocardial infarction, ventricular enlargement is progressive and that captopril may attenuate this process, reduce filling pressures, and improve exercise tolerance.
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            • Record: found
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            The histopathologic evolution of myocardial infarction.

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              • Record: found
              • Abstract: not found
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              Late effects of acute infarct dilation on heart size: a two dimensional echocardiographic study.

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                Author and article information

                Journal
                Circulation
                Circulation
                Ovid Technologies (Wolters Kluwer Health)
                0009-7322
                1524-4539
                April 1990
                April 1990
                : 81
                : 4
                : 1161-1172
                Affiliations
                [1 ]Department of Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, MA 02115.
                Article
                10.1161/01.CIR.81.4.1161
                2138525
                © 1990

                Molecular medicine, Neurosciences

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