Left ventricular aneurysm repair in rats: Structural, functional, and molecular consequences

Objectives: This study examined the effects of aneurysm repair in a rat model of myocardial infarction on functional indices and on the spatiotemporal distribution of cardiac contractile protein and natriuretic peptide messenger RNA. Methods: In a rat infarct model, expanded left ventricular aneurysms were plicated 4 weeks after infarction. At 30 weeks, transverse heart sections were taken at 4 levels (apex [level 1] through base [level 4]) and assessed by in situ hybridization histochemistry to determine regional messenger RNA levels of pre-pro-atrial natriuretic peptide, cardiac α-actin, skeletal α-actin, myosin light chain-2v, and β-myosin heavy chain. Results: Rats with plicated left ventricular aneurysms had reduced left ventricular endocardial circumference (19%, P