Diastolic dysfunction and collagen structure in canine pacing-induced heart failure

Area of Science:

• Cardiology
• Biomedical Engineering
• Pathology

Background:

• Heart failure presents with both systolic and diastolic dysfunction.
• Diastolic dysfunction, a key feature, impacts cardiac tissue properties and collagen structure.
• Understanding these changes is crucial for diagnosing and treating heart failure.

Purpose of the Study:

• To investigate the association between diastolic dysfunction and changes in cardiac tissue properties.
• To analyze alterations in the collagen network structure in heart failure.
• To determine the relationship between collagen structure and left ventricular stiffness.

Main Methods:

• Heart failure was induced in dogs via rapid left ventricular pacing.
• Hemodynamic parameters and left ventricular dimensions were monitored using sonomicrometry.
• Collagen structure was analyzed using picrosirius red staining and polarized light microscopy.

Main Results:

• Heart failure led to increased left ventricular stiffness, indicated by a steeper end-diastolic pressure-strain relation.
• Collagen volume fraction remained unchanged, but collagen fiber orientation became significantly more nonuniform.
• Increased collagen fiber orientation nonuniformity correlated strongly with increased left ventricular stiffness.

Conclusions:

• Diastolic dysfunction in heart failure is associated with increased left ventricular stiffness.
• The structural basis for this stiffness involves altered collagen network organization, specifically increased disorientation.
• These findings highlight the role of collagen remodeling in the mechanical dysfunction of the failing heart.