The isolated working heart model in infarcted rat hearts

Area of Science:

• Cardiology
• Physiology
• Animal Models

Background:

• Congestive heart failure (CHF) is a leading cause of death in Western countries.
• Current treatments for heart failure are largely palliative.
• Developing predictive animal models is crucial for advancing heart failure research.

Purpose of the Study:

• To establish and validate a working heart model in rats with induced congestive heart failure (CHF).
• To evaluate cardiodynamics and geometric properties of the left ventricle in this model.
• To adapt existing formulae for accurate parameter determination in infarcted rat hearts.

Main Methods:

• Congestive heart failure (CHF) was induced in Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) via permanent left coronary artery occlusion.
• The 'working heart' model was utilized to assess cardiodynamics, including contractility.
• Left ventricular geometric properties were measured using planimetry (stereology).

Main Results:

• The spontaneously hypertensive rat (SHR) model exhibited characteristic CHF parameters and symptoms (NYHA III-IV) 8-12 weeks post-myocardial infarction (MI).
• SHR rats displayed severe clinical signs of CHF, including dyspnea and edema, and pathological findings like pulmonary edema and ventricular dilation.
• The working heart model revealed reduced heart power and contractility in infarcted rats, particularly in SHR compared to WKY rats.

Conclusions:

• The established working heart model in SHR rats with myocardial infarction (MI) accurately replicates end-stage CHF.
• This validated model provides a valuable platform for the early testing of novel therapeutic strategies for CHF.
• Further research using this model can accelerate the development of causal therapies for heart failure.