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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ebstein's anomaly of the tricuspid valve is associated with right ventricular dilatation in approximately two-thirds of cases. Dilatation may be massive. It involves not only the right ventricular wall proximal to the tricuspid valve (atrialized ventricle) but also the right ventricle distal to the valve (funtional right ventricle), including the right ventricular infundibulum. For further definition of the pathogenesis of dilatation of the functional right ventricle (distal chamber), a morphometric histopathologic study was performed on 10 hearts with Ebstein's anomaly and 10 normal age-matched control hearts. In the group with Ebstein's anomaly, five hearts exhibited dilated ventricles and five did not. The study demonstrated that dilatation of the right ventricle in Ebstein's anomaly was associated not only with thinning of the wall but also with an absolute decrease in the number of myocardial fibers counted through the thickness of the wall from endocardium to epidcardium.
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PMID:The right ventricular myocardium in Ebstein's anomaly: a morphometric histopathologic study. 43 Nov 24

To assess the early topographic changes after acute transmural myocardial infarction, we studied 28 patients during the first two weeks after infarction by serial two-dimensional echocardiography. Regional end-diastolic segment lengths and wall thicknesses for anterior and posterior left ventricular walls were calculated. Eight patients showed infarct expansion, with disproportionate dilatation and transmural thinning in the infarcted zone, that was significantly different (P less than 0.005) from changes in non-infarcted regions. This regional expansion led to an overall left ventricular dilatation in these eight patients of 25 per cent compared to 5 per cent in the 20 patients without infarct expansion. Although the eight patients with regional expansion did not have significantly higher peak creatine kinase or Killip classification, they had a significantly greater eight-week mortality (four of eight versus none of 20, P less than 0.004). Thus, regional cardiac dilatation may be an early, lethal consequence of transmural infarcts, and appears to be an important mechanism of acute cardiac dilatation after myocardial infarction.
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PMID:Regional cardiac dilatation after acute myocardial infarction: recognition by two-dimensional echocardiography. 75 78

During five years from 1985 to 1989, serial brain echography was performed in 399 preterm infants with gestation less than 35 weeks at Kitasato University Hospital. Twenty-eight (7.0%) infants without periventricular hemorrhage were revealed as having spastic cerebral palsy by neurodevelopmental evaluation in later infancy. Of these 28 infants, the following neonatal brain echographic findings were obtained; cystic periventricular leukomalacia in 14, and persistent periventricular echogenicity without cystic formation in 4. However, neonatal brain echograms were completely normal in 10 infants. Magnetic resonance (MR) studies were performed to find cerebral lesions in all 28 infants. Periventricular high intensity areas on T2 weighted images, irregularity of ventricular wall, ventricular dilatation, decreased volume in periventricular white matter and thinning of the posterior body of corpus callosum were common findings in those infants, and compatible with the MR findings of periventricular leukomalacia (PVL). Therefore our infants with no brain echo abnormality might have had small PVL lesions not detected by brain echography. The reliability of brain echography is still controversial in the diagnosis of nonhemorrhagic PVL. Careful follow up is essential even in the infant with no brain echo abnormality.
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PMID:[Imaging evolution and incidence of periventricular leukomalacia in preterm infants]. 156 49

Early in the acute phase of myocardial infarction the phenomenon of expansion may occur, with regional thinning and dilatation of necrotic region. This complication may be detected by echocardiography since the first hours of infarction. During the two subsequent weeks, an additional increase of left ventricular volume may occur, due to an increase of length of the infarcted segments and, as well, of the contractile segments which suffer a "volume overload hypertrophy". This is the phenomenon of remodeling. Finally during the first year post infarction, a progressive left ventricular dilatation may develop. This late dilatation seems to be due to an increase of perimeter of the contractile regions only. By the time this topographic changes have occurred, the left ventricle assumes a more spheric configuration. Left ventricular dilatation affects adversely cardiac function, with higher incidences of heart failure and death. Experimental and clinical studies show that, in selected patients, remodeling and ventricular dilatation may be attenuated by the administration of angiotensin-converting-enzyme inhibitors, with better indices of left ventricular function. Final results of several on-going multicenter studies are awaited for; they will allow a better definition of the role of ACE inhibitors on prevention and treatment of left ventricular dysfunction after myocardial infarction.
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PMID:[Expansion of infarction, dilatation and ventricular remodelling. Therapeutic potential of angiotensin-converting enzyme inhibitors]. 161 Jun 13

An acute myocardial infarction, particularly one that is large and transmural, can produce expansion and alterations in the topography of both the infarcted and non-infarcted regions or the ventricle. This remodelling can importantly affect the function of the ventricle and the prognosis. Side-to-side slippage of myocytes in the myocardium occurring in association with ventricular dilatation is responsible for wall thinning. The increased internal load that is sustained through the cardiac cycle is thought to promote further stress, dilatation and hypertrophy of the non-infarcted area. The collagen network has been showed to be high responsible for the remodelling of the interstitium and therefore for the scar formation involved in the expansion. The process for ventricular enlargement can be influenced by infarct size, healing end ventricular wall stresses. The process of scarification can be interfered with during the acute infarct period by the administration of glucorticosteroids and non-steroidal anti-inflammatory agents, which results in thinner infarct and further expansion. A most effective way to prevent or minimize the increase in ventricular size is to limit the initial insult. Acute thrombolytic reperfusion therapy may work in this way. Finally early and long-term therapy with an angiotensin converting enzyme inhibitor can favorably alter the loading conditions of the left ventricle, reducing progressive enlargement with a prolongation in survival.
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PMID:[Left ventricular remodelling]. 184

An abnormal elevation in collagen concentration or myocardial fibrosis occurs in the hypertrophied left ventricle of the rat with renovascular hypertension (RHT). The structural nature and functional consequences of this fibrosis and the mechanisms involved in its appearance were reviewed for various phases of hypertrophy. Within days after the onset of renal ischemia, type I collagen messenger ribonucleic acid is expressed. An interstitial fibrosis follows, characterized by an increased dimension of existing perimysial fibers and the appearance of fibrillar collagen in spaces previously devoid of collagen, together with a perivascular fibrosis of intramyocardial coronary arteries. These expressions of myocardial fibrosis are associated with an increase in diastolic and systolic myocardial stiffness. Endomyocardial fibrosis serves to further increase diastolic stiffness while myocytes encircled by fibrillar collagen become atrophic. Each of these consequences of myocardial fibrosis reduce myocyte length-dependent force generation. At 32 weeks of RHT there is an obvious diastolic and systolic dysfunction of the ventricle together with heart failure that includes ventricular dilatation, wall thinning and reduced ejection fraction. The mechanisms involved in mediating fibrosis in RHT appear to be multiple. Myocyte necrosis and fibroblast proliferation have been associated with elevated circulating angiotensin II. Necrosis in RHT was not seen with captopril pretreatment or in the hypertension and hypertrophy that accompanied infrarenal aorta banding. An alteration in coronary artery permeability may be responsible for the perivascular fibrosis that is not seen with captopril pretreatment. Thus in RHT, the hemodynamic status of the ventricle determines myocyte hypertrophy while the elevation in circulating angiotensin II is responsible for the remodeling of nonmyocyte compartments, including the appearance of myocardial fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Myocardial fibrosis and pathologic hypertrophy in the rat with renovascular hypertension. 213 51

An important antecedent to the development of late congestive heart failure is left ventricular dilatation and remodeling following myocardial infarction, which occurs in 30-40% of acute anterior transmural infarcts. Dilatation and remodeling commence within the first 24 hours following myocardial infarction and may be steadily progressive over months to years. Both the infarcted and uninfarcted regions of the myocardium are equally involved in the process. The remodeling process comprises left ventricular wall thinning (mainly due to cell slippage), chamber dilatation, and compensatory hypertrophy of the uninfarcted segment of the myocardium. The hypertrophy may initially be physiologic but may ultimately become a pathologic process, and thereby contribute to pump dysfunction. The possible reasons why the ventricular hypertrophy may ultimately be dysfunctional include alterations in local architecture and their sequelae alone or in concert with local changes in the beta-adrenergic, alpha-adrenergic, or renin angiotensin systems. At the present time, there are encouraging data to suggest that nitroglycerin, or the angiotensin converting enzyme inhibitor captopril, may ameliorate this process.
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PMID:Left ventricular dilatation and failure post-myocardial infarction: pathophysiology and possible pharmacologic interventions. 214 59

Infarct expansion and infarct extension are events early in the course of myocardial infarction with serious short- and long-term consequences. Infarct expansion, disproportionate thinning, and dilatation of the infarct segment probably begin within hours of acute infarction and usually reach peak extent within seven to 14 days. Clinical data suggest that infarct expansion occurs in approximately 35% to 45% of anterior transmural myocardial infarctions and to a lesser extent in infarctions at other sites. Although expansion usually develops in large infarcts, the extent of transmural necrosis rather than absolute infarct size predicts its occurrence. Expansion has an adverse effect on infarct structure and function for several reasons. Functional infarct size is increased because of infarct segment lengthening, and expansion results in over-all ventricular dilatation. Thus, patients with expansion of an infarct have poorer exercise tolerance, more congestive heart failure symptoms, and greater early and late mortality than those without expansion. Infarct rupture and late aneurysm formation are two additional structural consequences of infarct expansion. Experimental and clinical data suggest that the incidence and severity of expansion can be modified by interventions. Increased ventricular loading conditions and steroidal and nonsteroidal antiinflammatory agents make expansion more severe. Reperfusion of the infarct segment and pharmacologic interventions that decrease ventricular afterload lessen the severity of expansion. Previous myocardial infarction and preexisting ventricular hypertrophy may also limit the development of infarct expansion. Infarct extension is defined clinically as early in-hospital reinfarction after a myocardial infarction. The pathologic finding of infarct extension is necrotic and healing myocardium of several different recent ages within the same vascular territory. Although this pathologic criterion usually cannot be verified, studies employing invasive and noninvasive assessment of patients with early reinfarction provide evidence that the new myocardial injury is usually in the same vascular risk region as the original infarction. A variety of different criteria have been applied in the clinical diagnosis of infarct extension, and this has resulted in a large range of estimated frequencies from under 10% to as high as 86%. High estimates are found in studies using one or two nonspecific criteria such as ST segment shift or reelevation of total CK. The lowest rates have been found when combinations of criteria are used.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Myocardial infarct expansion, infarct extension, and reinfarction: pathophysiologic concepts. 288 58

We investigated the natural course of 59 patients with hypertrophic cardiomyopathy (HCM) in follow-up periods of one to 13 years and analyzed the clinical, hemodynamic and echocardiographic parameters to determine the factors influencing the prognosis. Among these patients, 44 (75%) remained stable in a compensated condition with or without medications. Five patients died suddenly and two died of congestive heart failure. Heart failure developed in another eight. At the initial evaluation, these 15 patients had high left ventricular end-diastolic pressure (mean: 22 +/- 8 mmHg) significantly higher than that of 44 compensated patients (mean: 13 +/- 6 mmHg, p less than 0.001). There were no differences in age at the initial evaluation between compensated and end stage groups. Atrial fibrillation occurred persistently in three and transiently in two among ten patients with heart failure during follow-up periods. Ventricular dimensions and systolic function did not statistically differ between the two groups. However, six patients with heart failure had cavity dilatation and deteriolated ventricular contractile function at the initial evaluation. Four of them did not show any change in left ventricular hypertrophy, but the regional thinning of the wall was observed in the remaining two. There were no characteristic features to predict sudden death in the clinical, hemodynamic or echocardiographic parameters. Thus, increased left ventricular end-diastolic pressure, atrial fibrillation, left ventricular dilatation and the regional thinning of the left ventricular wall are useful predictive markers for poor prognosis in HCM.
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PMID:[Natural course of hypertrophic cardiomyopathy: clinical, hemodynamic and echocardiographic features in the end stage]. 297 74

Serial two-dimensional echocardiographic and thallium-201 scintigraphic findings are described in a patient with acute myocarditis diagnosed by endomyocardial biopsy. On the 4th day of illness, just before the onset of congestive heart failure, the echocardiogram showed asymmetric septal hypertrophy (IVS/PW = 16 mm/10 mm = 1.6) and thallium-201 scintigram showed the ventricular septal thickening. On the 8th day of illness, when severe congestive heart failure was seen, asymmetric septal hypertrophy disappeared (IVS/PW = 8 mm/8 mm = 1.0), the left ventricle dilated markedly (LVDd = 63 mm), and the wall motion became poor (EF = 0.24). After one month, when congestive heart failure and clinical inflammatory findings disappeared, the contractility somewhat improved (EF = 0.43), although marked left ventricular dilatation remained. Thallium-201 scintigram showed some scattered persistent perfusion defects, thinning of the ventricular septal thickening, and dilatation of the left ventricle. The right ventricular endomyocardial biopsy revealed the histologic findings of the late stage of acute myocarditis. It is concluded that transient thickening of the ventricular wall may represent early changes in acute myocarditis.
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PMID:Reversible asymmetric septal hypertrophy in acute myocarditis. Serial findings of two-dimensional echocardiogram and thallium-201 scintigram. 316 41


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