Acute myocardial infarction: biological role of postinfarction tissue
Malyshev I. I., Romanova
L. P., Vorobyova O. V.
ABSTRACT
This study aimed
to analyze morphological changes of postinfarction
tissue during the restorative period after acute myocardial infarction (AMI),
which, in our opinion, can change the perception of AMI in terms of its
biological significance.
Methods. Objects
of the study were cardiac biopsy specimens from 27 AMI patients who died
in the hospital within 7 to 34 days after the onset of AMI, as well as heart
biopsy specimens from 8 people aged 45 to 61 years old
who deceased due to an unnatural cause (car accident) and whose autopsies
revealed large foci of postinfarction tissue. The
deceased patients had history of coronary heart disease (CHD) and arterial
hypertension (AH).
Results. During
the autopsy we diagnosed extensive intramural
myocardial infarctions localized in the anterior-lateral walls of the left
ventricle with the infarction zone spreading to the apex and the anterior part
of the interventricular septum. All deceased patients had a severe
atherosclerotic lesion in left anterior descending artery; thrombotic masses were revealed in the upper third of coronary artery in 19
deceased patients (11 men and 8 women). Postinfarction
fibrous tissue was detected at the infarction site on
average by 29 to 30 days after the onset of AMI. The special feature was that
its fibers were oriented parallel to the preserved muscle fibers, and the
remains of the preserved muscle tissue fibers, breaking on the border with the
infarction site, were continued by the fibers of newly formed postinfarction connective tissue. There was a small amount
of glycogen and oxidation-reduction enzymes present in the postinfarction
tissue, which were also present in the preserved cardiomyocytes.
Conclusion. Thus,
according to the results obtained, AMI is a compensatory-adaptive process
aimed at correcting the anatomical-physiological mismatch between hypertrophied
myocardium and the state of coronary vessels affected by atherosclerotic
process in postnatal (often late) ontogenesis.
Key words: myocardial infarction, regeneration, compensatory-adaptive process,
vascular atherosclerosis.
For citation:
Malyshev I., Romanova LP, Vorobyova OV Acute myocardial infarction: biological role
of postinfarction tissue. International Journal of
Heart and Vascular Diseases. 2023;
11(38):31-34. DOI:10.24412/2311-1623-2023-38-37-42