Characteristics of chronic left ventricular dysfunction induced by coronary embolization in a canine model

Area of Science:

• Cardiovascular Science
• Heart Failure Research
• Animal Models of Disease

Background:

• Chronic heart failure (CHF) is a complex syndrome with significant morbidity and mortality.
• Understanding the pathophysiology of CHF is crucial for developing effective treatments.
• Animal models are essential for studying disease mechanisms and testing interventions.

Purpose of the Study:

• To characterize coronary vascular reserve, left ventricular function, and inotropic response in a canine model of chronic heart failure.
• To investigate the structural changes associated with chronic heart failure induced by embolization.
• To compare findings in the heart failure model with normal control dogs.

Main Methods:

• Induction of chronic heart failure in dogs via intracoronary embolization (EMB) with 50-micron spheres.
• Assessment of coronary vascular reserve, left ventricular (LV) function, and inotropic responses 12-39 months post-embolization.
• Histological analysis using light and electron microscopy to evaluate myocardial structure and fibrosis.

Main Results:

• Embolization led to sustained LV volume enlargement, increased wall thickness, reduced ejection fraction, and elevated end-diastolic pressures.
• Coronary vasodilator reserve was reduced in EMB dogs, despite increased coronary vascular volume.
• Histological analysis revealed diffuse fibrosis and a 14% loss of myocytes, disrupting myocardial architecture.

Conclusions:

• This canine model of chronic heart failure exhibits LV systolic dysfunction and elevated diastolic pressures, mirroring human conditions.
• The observed fibrosis and myocyte loss contribute to impaired cardiac function and reduced coronary vasodilator reserve.
• The model provides valuable insights into the pathophysiology of congestive heart failure and its structural basis.