Document Type : Original Article
Authors
1
Cardiovascular Research Center, Rajaie Cardiovascular Institute, Tehran, Iran.
2
Department of Internal Medicine, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.
3
Department of Surgery and Radiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. & Institute of Biomedical Research, University of Tehran, Tehran, Iran.
4
Institute of Biomedical Research, University of Tehran, Tehran, Iran.
5
Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
6
Institute of Biomedical Research, University of Tehran, Tehran, Iran. & Department of Animal and Poultry Health and Nutrition, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.
7
Azadi avenueDepartment of Internal Medicine, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. & Institute of Biomedical Research, University of Tehran, Tehran, Iran.
Abstract
Background: Myocardial infarction (MI), commonly known as a heart attack, is a major manifestation of cardiovascular disease and a leading cause of death. Characterizing the pathophysiological consequences of MI in an appropriate animal model is essential for translational research. Therefore, this study investigated changes in clinical signs, arterial blood gases, electrolyte concentrations, and acid–base parameters 24 hours after experimentally induced MI in sheep to further characterize this large-animal model for translational research.
Methods: Six healthy male sheep were included in this experimental study. After confirmation of health status, myocardial infarction (MI) was induced through left lateral thoracotomy and ligation of a lateral branch of the left anterior descending (LAD) coronary artery. Clinical cardiovascular, respiratory, and general findings were recorded and scored, and arterial blood was collected from the auricular artery for blood gas and electrolyte analysis before surgery and 24 hours after MI induction.
Results: Compared with baseline, heart rate and respiratory rate increased significantly 24 hours after MI induction. Significant changes were also observed in heart rhythm, heartbeat intensity, heart and respiratory sounds, mucous membrane appearance, appetite, and general physical condition. Tachycardia, tachypnea, reduced heartbeat intensity, irregular cardiac rhythm, additional heart sounds, predominantly crackles on respiratory auscultation, mucosal hyperemia, reduced appetite, and depressed or withdrawn behavior were observed. Arterial blood analysis showed significant decreases in PO2, SatO2, base excess (BE), and K+, as well as significant increases in PCO2, Na+, Cl-, and anion gap.
Conclusion: Experimental MI in sheep is associated with significant cardiopulmonary and biochemical changes 24 hours after induction. The reduced BE and increased anion gap indicate a shift toward increased metabolic acid burden, accompanied by a significant rise in arterial PCO2. Since arterial pH remained unchanged, these findings should not be interpreted as overt mixed metabolic and respiratory acidemia.
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