Noninvasive and Invasive Study of the Pumping Function of Rat Heart in Myocardial Infarction

Area of Science:

• Cardiovascular Physiology
• Experimental Cardiology
• Animal Models of Heart Disease

Background:

• Myocardial infarction (MI) significantly alters cardiac function and hemodynamics.
• Accurate assessment of left ventricle (LV) volume and function is crucial for understanding MI progression.
• Echocardiography (echoCG) and left ventricle catheterization are common diagnostic tools.

Purpose of the Study:

• To compare the accuracy of echocardiography (echoCG) and left ventricle catheterization in assessing cardiohemodynamics after myocardial infarction.
• To evaluate changes in LV dimensions, ejection fraction, and relaxation post-MI.
• To investigate potential discrepancies between echoCG and catheterization in volume measurements.

Main Methods:

• Myocardial infarction was induced in Wistar rats by ligating the left anterior descending coronary artery.
• Cardiohemodynamics were assessed using echocardiography (echoCG) and left ventricle catheterization at 2 and 4 weeks post-MI.
• Measurements included LV volume, ejection fraction, and relaxation parameters.

Main Results:

• Both echoCG and catheterization revealed LV dilatation, bradycardia, reduced ejection fraction, and delayed relaxation post-MI.
• EchoCG showed a 2-fold increase in end-diastolic LV volume and a >5-fold increase in initial diastolic LV volume.
• Catheterization indicated lower increases of 32% and 69% for the respective volumes, suggesting echoCG may overestimate LV volume.

Conclusions:

• Echocardiography and left ventricle catheterization provide comparable qualitative assessments of hemodynamic changes after myocardial infarction.
• EchoCG may overestimate left ventricle volumes in post-MI models due to altered ventricular geometry (e.g., wall bulging).
• Careful interpretation of echoCG volume data is warranted in the context of significant geometric remodeling following myocardial infarction.