Early postinfarction ventricular restraint improves borderzone wall thickening dynamics during remodeling.

Area of Science:

• Cardiovascular Research
• Regenerative Medicine
• Biomedical Engineering

Background:

• Early infarct expansion impairs borderzone myocardium (BZM) function and leads to adverse remodeling after myocardial infarction (MI).
• Ventricular restraint has shown promise in improving global cardiac remodeling post-MI.
• The specific effects of early ventricular restraint on BZM function remain largely unassessed.

Purpose of the Study:

• To investigate the hypothesis that early ventricular restraint preserves BZM function and reduces remodeling following MI.
• To evaluate the impact of a cardiac support device (CSD) on BZM contractile function and global ventricular remodeling.

Main Methods:

• Utilized an ovine model with induced anterior myocardial infarction (MI).
• Placed a cardiac support device (CSD) in 3 sheep one week post-MI to restrain infarct expansion.
• Assessed global remodeling and borderzone (BZM) wall thickening strain using tagged MRI before and 8 weeks after infarction.

Main Results:

• The CSD group exhibited significantly reduced global remodeling compared to controls.
• While baseline BZM systolic wall thickening was similar, controls showed a significant decrease after 8 weeks (4.9% +/- 0.7%).
• The CSD group preserved BZM systolic wall thickening at 8 weeks (11.0% +/- 1.6%), indicating improved contractile function.

Conclusions:

• Early ventricular restraint via a CSD improves both the contractile function of the borderzone myocardium (BZM) and global ventricular remodeling after MI.
• Remodeling processes impair the dynamics of BZM wall thickening.
• The CSD significantly enhances BZM wall thickening dynamics but does not fully restore them to baseline levels.