Pathogenesis of left ventricular aneurysms: an experimental study in the rat model

Area of Science:

• Cardiovascular Research
• Pathophysiology
• Myocardial Infarction

Background:

• Left ventricular aneurysms are late complications of myocardial infarction.
• The timing of aneurysm development (early dilation vs. late scar dilation) remains unclear.

Purpose of the Study:

• To investigate the temporal development of left ventricular aneurysms after myocardial infarction.
• To determine if aneurysms arise from early myocardial changes or late scar remodeling.

Main Methods:

• Myocardial infarcts were induced in 141 rats via coronary ligation.
• Rats were observed for up to 6 weeks post-infarction.
• Left ventricular shape changes and dilation were assessed over time.

Main Results:

• True left ventricular aneurysms developed as early as 2 weeks post-infarction in rats with transmural infarcts.
• Aneurysmal shape changes increased significantly between days 1 and 5, then plateaued.
• Early aneurysmal shape changes did not show significant progression in dilation up to 42 days.

Conclusions:

• Left ventricular aneurysms in rats result from the expansion of freshly necrotic myocardium within the first 5 days.
• Early alterations in left ventricular shape are critical determinants of late aneurysm formation.
• Findings suggest early post-infarction events, not late scar changes, drive aneurysm development.