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Updated: Jun 22, 2026
Acute Myocardial Infarction in Rats
Published on: February 17, 2011
Chronic coronary artery constriction leads to moderate myocyte loss and left ventricular dysfunction and failure in
Insights
Coronary artery narrowing in rats caused significant cardiac dysfunction and failure. This led to ventricular remodeling, myocyte loss, and compensatory hypertrophy, impacting cardiac dynamics.
Area of Science:
- Cardiovascular Research
- Pathophysiology
- Animal Models
Background:
- Coronary artery disease is a leading cause of heart failure.
- Understanding the cardiac remodeling process following coronary narrowing is crucial.
Purpose of the Study:
- To investigate the effects of induced coronary artery narrowing on ventricular performance, myocardial damage, and myocyte hypertrophy in rats.
- To characterize the progression from cardiac dysfunction to failure.
Main Methods:
- Induction of coronary artery narrowing (19%-61%) in rats.
- Assessment of ventricular performance, myocardial damage, and myocyte hypertrophy 1 month post-induction.
- Separation of animals into ventricular dysfunction and failure groups based on hemodynamic parameters.
Main Results:
- Coronary narrowing induced significant increases in left ventricular end diastolic pressure (LVEDP) and right ventricular pressures.
- Ventricular dysfunction and failure groups showed decreased left ventricular peak systolic pressure (LVPSP), developed pressure (DP), and dP/dt values.
- Animals exhibited ventricular dilation, wall thinning, myocyte loss, and compensatory hypertrophy, with more severe changes in the failure group.
Conclusions:
- Induced coronary narrowing leads to cardiac abnormalities, including increased diastolic wall stress and ventricular remodeling.
- Compensatory hypertrophy of viable myocytes occurs despite myocyte loss.
- The study provides insights into the pathophysiology of heart failure secondary to coronary artery disease.
Abstract:
Coronary artery narrowing, ranging from 19% to 61%, was induced in rats and ventricular performance, myocardial damage, and myocyte hypertrophy were examined 1 mo later. Animals were separated into two groups, exhibiting ventricular dysfunction and failure, respectively. Dysfunction consisted of a 2.4-fold increase in left ventricular end diastolic pressure (LVEDP), 15% decrease in left ventricular peak systolic pressure (LVPSP), 24% reduction in developed pressure (DP), and a 16% depression in-dP/dt. Failure was defined on the basis of a 4.7-fold elevation in LVEDP, and a 26%, 47%, 45%, and 41% decrease in LVPSP, DP, +dP/dt, and -dP/dt. Moreover, in this group, right ventricular end diastolic and systolic pressures increased 5.5- and 1.2-fold. Left and right ventricular weights expanded 23% and 51% with dysfunction and 30% and 56% with failure. Left ventricular hypertrophy was characterized by ventricular dilation and wall thinning which were more severe in the failing animals. Foci of damage were found in both groups but tissue injury was more prominent in the endomyocardium and in failing rats. Finally, myocyte loss in the ventricle was 10% and 20% with dysfunction and failure whereas the corresponding enlargements of the unaffected myocytes were 34% and 53%. Thus, coronary narrowing led to abnormalities in cardiac dynamics with an increase in diastolic wall stress and extensive ventricular remodeling in spite of a moderate loss of myocytes and compensatory reactive hypertrophy of the viable cells.
