[Changes in the diameter and length of hypertrophic cardiomyocytes in the dilated left ventricle of cardiac surgical patients]. / Izmenenie diametra i dliny gipertrofirovannykh kardiomiotsitov dilatirovannogo levogo zheludochka u kardiokhirurgicheskikh bol'nykh.

AIM: to investigate changes in the diameter and length of hypertrophic cardiomyocytes (CMCs) in the dilated left ventricle (LV). SUBJECTS AND METHODS: Light microscopy, morphometry, and statistical analysis were used to investigate the status of the contractile apparatus and changes in the length, diameter of CHC and diameter of CMC nuclei, by using intraoperative dilated LV biopsy samples from 31 patients with valvular disorders and dilated cardiomyopathy. Morphological findings were compared with the clinical parameters of the patients. RESULTS: CMCs in the patients with the dilated LV were hypertrophic and were at different stages of restructuring with progressive myofibrillar loss (PML). In 81% of patients, the diameter of CMCs was not significantly changed as their zones of PML extended. The length of CMCs, which correlated with the enlarged LV cavity, was increased in 52% of patients during cell restructuring with PML. In 42% of patients, the CMC nuclear diameter increased during restructuring with PML, which appeared to be associated with CMC polyploidization; in some of these patients (19% of the total number of patients), the diameter of CMCs increased in parallel with the higher diameter of their nuclei. CONCLUSION: The findings suggest that after completion of their transverse growth, hypertrophic CMCs are involved in a restructuring process with PML. The findings are consistent with the hypothesis that dilatation of the hypertrophied LV cavity is related to the preferential elongation of CMCs with an inadequate increase in their diameter. The results of the investigation may assume that the higher CMC diameter that brings to completion before the entry of the cells into the restructuring process with PML, resumes in the cells, the ploidy of which increases in the course of restructuring with PML, triggering an additional mechanism for raising the CMC diameter at this stage of myocardial hypertrophy. The results are indicative of different mechanisms for increasing the diameter and length of hypertrophic CMCs, since the diameter of CMCs directly correlates with that of their nuclei, and the length increases as the zones of PML extend in the CMCs.

[Cardiomyocyte structural rearrangement in patients with dilated cardiomyopathy and valvular heart disease].

Light and electron microscopies were used to analyze cardiomyocyte structural changes in the dilated left ventricle in patients with dilated cardiomyopathy and valvular heart diseases. The patients were found to have cardiomyocyte hypertrophy and ultrastructural rearrangement with a tissue-specific reduction. There was hypertrophic cardiomyocyte lengthening that continued after these cells stopped growing thicker, as well as occurred due to the loss of myofibrils, which increased during the cell rearrangement, and directly correlated with the lower ejection fraction and higher end-systolic volume of the left ventricle.

[Left ventricle dilatational lesion. Problems of nosology, diagnostics, and treatment].

The article deals with the problem concerning the use of the term "specific cardiomyopathy", adopted by WHO in 1995, in cases of advanced left ventricle lesion in patients with valvular heart defects. The group of patients with dilated left ventricle cavity, related to acquired heart diseases, is rather heterogeneous and large in number, and includes about 50% of the patients who underwent an operation. In the authors' opinion, it is reasonable to divide them into the following main subgroups: patients with quickly regressing symptomatic left ventricle dilatation, resulting from volume overload; patients with valvular cardiomyopathy (the terminal stage of heart defect); patients with left ventricle dilatational lesion, typical of the intermediate stage with characteristic pathological remodeling and the disturbance of its segmental contractility. The authors consider such a division to be useful for further study of patients with left ventricle dilatation due to valvular heart defects.