Smoke-like echo in the left atrial cavity in mitral valve disease: Its features and significance

In some patients with mitral stenosis, a smoke-like echo is observed in the left atrial cavity. The present study in 116 consecutive patients with rheumatic mitral valve disease investigated the echocardiographic features and clinical significance of this echo. The smoke-like echo is characterized by the following echocardiographic features: 1) it is composed of numerous microechoes; 2) it curls up slowly in the enlarged left atrial cavity; and 3) it vanishes as soon as it pours into the ventricular cavity. Hemostasis in the left atrial cavity was considered to be an important underlying condition for development of the echo. Hemorheologic conditions indicated that the shear rate of blood flow in the left atrial cavity was calculated to be low enough for the development of red blood cell aggregation.These conditions suggest that the source of the smokelike echo might be aggregated cells due to hemostasis in the left atrial cavity. Left atrial thrombi were detected in many patients who had this echo in the left atrial cavity. Although it has not been conclusively determined that the presence of the smoke-like echo is a necessary condition for thrombus formation, this echo appears to be closely related to thrombus formation in the left atrial cavity. It is concluded that the presence of this echo indicates severe left atrial hemostasis and is a warning for thrombus formation

Human matrix metalloproteinases: An ubiquitarian class of enzymes involved in several pathological processes

Human matrix metalloproteinases (MMPs) belong to the M10 family of the MA clan of endopeptidases. They are ubiquitarian enzymes, structurally characterized by an active site where a Zn(2+) atom, coordinated by three histidines, plays the catalytic role, assisted by a glutamic acid as a general base. Various MMPs display different domain composition, which is very important for macromolecular substrates recognition. Substrate specificity is very different among MMPs, being often associated to their cellular compartmentalization and/or cellular type where they are expressed. An extensive review of the different MMPs structural and functional features is integrated with their pathological role in several types of diseases, spanning from cancer to cardiovascular diseases and to neurodegeneration. It emerges a very complex and crucial role played by these enzymes in many physiological and pathological processes

A three-valued temporal logic for future contingents

It is now recognized that Lukasiewicz’s three-valued logic cannot supply a satisfactory treatment of future contingents. The defense of Lukasiewicz’s three-valued logic can be found in the work of Prior. Inspired by Prior’s suggestions to future contingents, we propose a new three-valued temporal logic FCP, in which the interpretation of negation differs from Lukasiewicz’s negation. It is shown in the logic that contingent propositions have the indeterminate truth-value while logically true propositions like the law of excluded middle have the determinate truth-values. We discuss some features of the proposed logic in comparison with the other approaches to future contingents in the literature

High prevalence of atrial fibrosis in patients with dilated cardiomyopathy

Objectives.We examined the extent of fibrotic changes in the left atrium of cardiomyopathic human hearts and investigated the relation of mechanical overload caused by left ventricular dysfunction to fibrosis of the left atrium.Background.Left atrial dysfunction in dilated cardiomyopathy may contribute to progression of heart failure. In contrast to fibrosis of the left ventricle, atrial fibrosis has not been extensively studied in cardiomyopathic hearts.Methods.The extent of fibrosis in the left atrium and left ventricle was determined by an automatic image analyzer in 38 autopsied hearts obtained from 9 patients who died of noncardiac illness (control group), 16 patients with dilated cardiomyopathy, 6 patients with hypertrophic cardiomyopathy with features mimicking dilated cardiomyopathy and 7 patients with a previous myocardial infarction. Transverse sections were obtained at the upper margins of the foramen ovale and left auricle in the left atrium and the median level of the left ventricle.Results.There were no significant differences in extent of left atrial dilation, left ventricular dysfunction or duration of illness among the three groups with cardiac disease. Percent area of left atrial fibrosis (mean ± SD) was significantly greater in the specimens from patients with dilated cardiomyopathy (13.1 ± 6.1%, p < 0.01) and hypertrophic cardiomyopathy mimicking dilated cardiomyopathy (26.5 ± 9.5%, p < 0.01) than in those from patients with an old myocardial infarction (3.8 ± 1.1%). Percent area of left ventricular fibrosis in hearts from patients with dilated cardiomyopathy (12.9 ± 8.6%) was significantly smaller than that in hearts from patients with hypertrophic cardiomyopathy mimicking dilated cardiomyopathy (35.8 ± 11.9%, p < 0.01) and a previous myocardial infarction (38.4 ± 8.0%, p < 0.01). Percent area of atrial fibrosis was significantly correlated with left ventricular ejection fraction in the group with a previous myocardial infarction but not in the other groups.Conclusions.There was a high degree of fibrotic change in the left atrium in the groups with dilated cardiomyopathy and hypertrophic cardiomyopathy mimicking dilated cardiomyopathy. Our findings suggest that atrial fibrosis in these patients may not have been related to mechanical overload of the left atrium but to some other, still unknown mechanisms

Salutary effect of disopyramide on left ventricular diastolic function in hypertrophic obstructive cardiomyopathy

ObjectivesThe purpose of this study was to estimate the effect of disopyramide on left ventricular diastolic function in patients with hypertrophic obstructive cardiomyopathy.BackgroundAlthough disopyramide has been reported to lessen clinical symptoms in patients with hypertrophic obstructive cardiomyopathy, few data exist regarding its effect on diastolic function in these patients.MethodsThirteen patients with hypertrophic cardiomyopathy (six with and seven without left ventricular outflow obstruction) were examined. Before and after intravenous disopyramide, hemodynamic and angiographic studies were performed.ResultsIn patients with outflow obstruction, pressure gradient at the outflow tract decreased from a mean ± SD of 100 ± 45 to 26 ± 33 mm Hg (p < 0.01). Although systolic function was similarly impaired in both groups, the time constant of left ventricular pressure decay (τ) shortened from 56 ± 10 to 44 ± 8 ms (p < 0.01) and the constant of left ventricular chamber stiffness (kc) decreased from 0.049 ± 0.017 to 0.038 ± 0.014 m2/ml (p < 0.01) only in patients with outflow obstruction. Shortening in τ correlated best with decrease in left ventricular systolic pressure (r = 0.84, p < 0.01). In contrast, τ was prolonged from 52 ± 10 to 64 ± 11 ms (p < 0.01) and kc was unchanged in patients without outflow obstruction.ConclusionsThe primary effects of disopyramide on the hypertrophied left ventricle were negative inotropic and negative lusitropic. However, left ventricular diastolic properties in patients with outflow obstruction were improved with a decrease in outflow pressure gradient. Relief of clinical symptoms in hypertrophic obstructive cardiomyopathy with disopyramide might be due in part to improvement of diastolic function, which appears secondary to the reduction in ventricular afterload