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Updated: Jun 1, 2026
Histological Quantification of Chronic Myocardial Infarct in Rats
Published on: December 11, 2016
Echocardiographic detection of congestive heart failure in postinfarction rats
Paula F Martinez1, Katashi Okoshi, Leonardo A M Zornoff
1Internal Medicine Department, Botucatu Medical School, Universidade Estadual Paulista, Botucatu, Brazil.
Insights
Diagnosing congestive heart failure (CHF) in postinfarction rats is simplified using echocardiography. This study shows echocardiographic criteria can accurately predict heart failure in rats without invasive hemodynamic evaluation.
Area of Science:
- Cardiovascular Research
- Animal Models
- Diagnostic Imaging
Background:
- Selecting appropriate animal models for congestive heart failure (CHF) studies requires accurate assessment of cardiac dysfunction.
- Hemodynamic evaluation is typically necessary but invasive for diagnosing postinfarction CHF in rats.
Purpose of the Study:
- To develop and validate a non-invasive method for diagnosing CHF in long-term postinfarction rats using echocardiography.
- To differentiate between rats with and without heart failure post-myocardial infarction (MI) based solely on echocardiographic parameters.
Main Methods:
- Utilized J-tree cluster analysis and Fisher's linear discriminant function on six echocardiographic variables.
- Studied two sets of sham and infarcted rats for cluster analysis and prospective validation.
- Histological analysis determined infarct size for pathological correlation.
Main Results:
- Cluster analysis identified distinct groups: sham, MI without heart failure (MI/HF-), and MI with heart failure (MI/HF+).
- MI/HF+ rats exhibited significantly more severe cardiac dysfunction and larger infarct sizes compared to MI/HF- rats.
- Fisher's discriminant function achieved high specificity (100%) and variable sensitivity (58.8%-80%) in prospectively classifying CHF.
Conclusions:
- Echocardiographic analysis, combined with statistical methods, can accurately predict and diagnose congestive heart failure in postinfarction rat models.
- This non-invasive approach facilitates better selection of animal models for CHF research, reducing the need for invasive hemodynamic measurements.
Abstract:
In studies of congestive heart failure (CHF) treatment, it is essential to select animals with a similar degree of cardiac dysfunction. However, this is difficult to establish without hemodynamic evaluation in rat postinfarction-induced CHF. This study aimed to diagnose CHF in long-term follow-up postinfarction rats using only echocardiographic criteria through a J-tree cluster analysis and Fisher's linear discriminant function. Two sets of sham and infarcted rats were studied. The first was used to perform cluster analysis and the second to prospectively validate the results. Six months after inducing myocardial infarction (MI), rats were subjected to transthoracic echocardiography. Infarct size was measured by histological analysis. Six echocardiographic variables were used in the cluster analysis: left ventricular (LV) systolic dimension, LV diastolic dimension-to-body weight ratio, left atrial diameter-to-body weight ratio, LV posterior wall shortening velocity, E wave, and isovolumetric relaxation time. Cluster analysis joined the rats into one sham and two MI groups. One MI cluster had more severe anatomical and echocardiographic changes and was called MI with heart failure (MI/HF+, n = 24, infarct size: 42.7 ± 5.8%). The other had less severe changes and was called MI without heart failure (MI/HF-, n = 11, infarct size: 32.3 ± 9.9%; P < 0.001 vs. MI/HF+). Three rats with small infarct size (21.6 ± 2.2%) presenting mild cardiac alterations were misallocated in the sham group. Fisher's linear discriminant function was built using these groups and used to prospectively classify additional groups of sham-operated (n = 20) and infarcted rats (n = 57) using the same echocardiographic parameters. The discriminant function therefore detected CHF with 100% specificity and 80% sensitivity considering allocation in MI/HF+ and sham group, and 100% specificity and 58.8% sensitivity considering MI/HF+ and MI/HF- groups, taking into account pathological criteria of CHF diagnosis. Echocardiographic analysis can be used to accurately predict congestive heart failure in postinfarction rats.