Myocardial ischemia and coronary artery atherosclerosis. A comprehensive approach to postmortem studies

Light and electron-microscopic studies on guinea pig hearts after perfusion with nitro-blue tetrazolium (NBT)

Guinea pig hearts isolated by the Langendorff technique were perfused with a nitro-blue tetrazolium salt solution. In spite of a homogeneous dark-blue staining at the macroscopic examination, light-microscopic studies showed a spotty staining of the myocardial fibers. Since no microscopic alterations were found which could explain the unstained areas, ultramicroscopic studies were undertaken. At ultrastructural level, striking alterations of myocardial cells were observed. They consisted of mitochondrial lesions, alterations of the transversal tubuli, and intercalated discs. Arteriolar narrowing and capillary edema were found, suggesting that pathological changes in the microcirculation could be a possible reason for the spotty staining of the myocardial fibers. Some speculations on the nature and localization of the formazan granules are also reported.

[Comparative enzyme-histochemical studies on normal myocardium, in cases of coronary insufficiency and myocardial infarction (author's transl)]

Comparative histochemical studies with Tetrazolium salt solutions were performed on 25 human and 3 canine hearts. After perfusion of whole hearts with Tetrazolium solutions extensive unstained areas were observed which proved to be artefacts, since they reacted positively after incubation of the heart-slices. The perfusion method of Lichtig, Feldman, Glagov and Wissler (1973) which was proposed for macroscopic and microscopic diagnosis of ischemic cardiac lesions was not found to be suitable for the identification of microcirculatory disturbances. The usual incubation method, however, proved to be useful for the macroscopic localization of recent myocardial infarcts.

Risk factors and coronary heart disease--facts or fancy?

The importance of the many well-published epidemiologic studies for the philosophy of prevention of ischemic heart disease has led to this analysis of the background design and early results of three such studies, i.e., the Framingham study, the National Pooling Project, and the Stockholm Prospective Study. Besides indicating certain flaws in the early design, it is demonstrated that the authors usually press their factual data to conclusions that are not only really valid, with some exceptions. This analysis leads to the conclusion that high blood pressure and cigarette smoking seem to be much more important for the development of ischemic heart disease than high serum lipids in the populations studied. They are, furthermore, selected in such a way that the results cannot have any bearing on the general population and, in particular, on its lower and higher social strata.

A new method for determination of postmortem left ventricular volumes: clinico-pathologic correlations

A description is presented of a new and simple procedure for ventricular volume determination by means of pressure fixation of the heart and preparation of plastic molds of the ventricles which can be used to displace water in a graduated cylinder to determine the volume of the mold. Correlations between postmortem ventricular volume as measured by this method and antemortem stroke volume or clinical cardiac status indicate that a large left ventricular volume is often correlated with a low cardiac output and cardiogenic shock.