Histological and morphometric changes in cardiac conduction fibers after spontaneous myocardial infarction in horses and dogs.
Abstract: Arrhythmic sudden cardiac death in dogs and horses often results from ventricular arrhythmia secondary to myocardial damage. Despite this, limited data exist on the histomorphometric changes in cardiac conduction fibers (CCFs) and cardiac conduction cells (CCCs) following spontaneous myocardial infarction (MI). This study aimed to characterize morphometric and histological alterations in conduction fibers and their junctions with cardiomyocytes in infarcted hearts of horses and dogs. Unassigned: Ten hearts from horses and 10 from dogs that had died suddenly were examined. Histological and immunohistochemical analyses were performed using hematoxylin and eosin, Masson's trichrome, and periodic acid-Schiff staining to identify conduction fibers and assess glycogen accumulation. The thickness and density of conduction fibers, as well as the diameter of conduction cells, were measured using image analysis software. Statistical comparisons were conducted using t-tests, analysis of variance, and Cohen's d-test. Unassigned: In horses, the diameter of CCCs was significantly smaller in infarcted cases (55.74 μm) compared to normal hearts (79.08 μm) (p < 0.001). In dogs, slight hypertrophy of CCCs (31.21 μm) was observed in normal hearts, whereas infarcted hearts exhibited reduced diameters (26.83 μm) (p = 0.114). The density of CCFs was 9.06% in horses and 7.99% in dogs (p = 0.846), while fiber thickness was 30.06 μm in horses and 29.86 μm in dogs (p = 0.263). Horses exhibited extensive myocardial fibrosis, particularly in the middle third and posterior left ventricle, while dogs displayed milder lesions distributed across the ventricle. Unassigned: This study demonstrates a reduction in CCC size in horses and minor hypertrophy in dogs, coupled with fibrotic myocardial lesions of varying severity. The observed histomorphometric changes provide insight into the structural impact of MI on conduction cells, which may contribute to ventricular arrhythmias in these species. These findings have implications for veterinary cardiology and the management of MI-related arrhythmic conditions.
Copyright: © Gómez-Torres, et al.
Publication Date: 2025-04-19 PubMed ID: 40453948PubMed Central: PMC12123274DOI: 10.14202/vetworld.2025.827-836Google Scholar: Lookup
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Summary
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This research article details the histological and morphometric changes in cardiac conduction fibers after spontaneous myocardial infarction (heart attacks) in horses and dogs. These changes may be linked to arrhythmic sudden cardiac death in these animals.
Study Methodology
- The researchers analyzed the hearts of ten horses and ten dogs that died suddenly.
- They performed histological and immunohistochemical analyses using various staining techniques to identify conduction fibers and evaluate glycogen buildup.
- Advanced image analysis software was utilized to measure the thickness and density of the conduction fibers and the diameter of the conduction cells.
- The results were evaluated using various statistical methods, including t-tests, the analysis of variance, and the Cohen’s d-test.
Study Findings
- The study found that in horses, conduction cells were significantly smaller in the infarcted cases compared to normal hearts.
- In dogs, slight hypertrophy (increase in size) of the conduction cells was observed in the normal hearts, but the infarcted hearts had reduced cell diameters.
- The researchers observed that the density of conduction fibers was approximately the same in horses and dogs, as was the thickness of the fibers.
- Horses presented extensive myocardial fibrosis, especially in the middle third and posterior left ventricle, whereas dogs displayed milder lesions distributed across the ventricle.
Implications of the Study
- This research outcomes show significant changes in cardiac conduction cells and fibers following spontaneous heart attacks in horses and dogs.
- The findings indicate a reduction in cell size in horses and minor hypertrophy in dogs, along with varying degrees of fibrotic lesions in the myocardium.
- These observations shed light on the structural impact of myocardial infarction on conduction cells, potentially contributing to ventricular arrhythmias in these animals.
- The research has important implications for vets specializing in cardiology and could influence the treatment management of myocardial infarction-related arrhythmic conditions.
Cite This Article
APA
Gómez-Torres F, Ballesteros-Acuña L, Ruíz-Sauri A.
(2025).
Histological and morphometric changes in cardiac conduction fibers after spontaneous myocardial infarction in horses and dogs.
Vet World, 18(4), 827-836.
https://doi.org/10.14202/vetworld.2025.827-836 Publication
Researcher Affiliations
- Department of Basic Sciences, School of Medicine, Universidad Industrial de Santander, Cra 32 # 29-31, 68002, Bucaramanga, Colombia.
- Department of Basic Sciences, School of Medicine, Universidad Industrial de Santander, Cra 32 # 29-31, 68002, Bucaramanga, Colombia.
- Department of Pathology, Faculty of Medicine and Odontology, University of Valencia, Av. de Blasco Ibáñez, 15. 46010. Valencia, Spain.
- INCLIVA Biomedical Research Institute, Av. de Blasco Ibáñez, 17. 46010, Valencia, Spain.
Conflict of Interest Statement
The authors declare that they have no competing interests.
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