Endomyocardial fibrosis and restrictive cardiomyopathy: pathologic and clinical features

Area of Science:

• Veterinary Cardiology
• Cardiovascular Pathology

Background:

• Restrictive cardiomyopathy (RCM) is a primary myocardial disorder known for diastolic dysfunction and diverse presentations.
• Clinicopathologic features of RCM in feline species are not well-established.
• A specific form of RCM involves endomyocardial fibrosis.

Purpose of the Study:

• To define the clinicopathologic features of restrictive cardiomyopathy (RCM) in cats.
• To characterize the pathological findings associated with endomyocardial fibrosis in feline RCM.

Main Methods:

• Review of clinicopathologic and histopathologic data from feline cases of restrictive cardiomyopathy.
• Detailed examination of endocardial and myocardial tissues for fibrosis and scarring.

Main Results:

• Endomyocardial fibrosis is a hallmark of feline RCM, characterized by severe endocardial scarring.
• Lesions may diffusely affect the left ventricle or form distinct scars, potentially reducing chamber volume and causing stenosis.
• Severe left atrial enlargement and variable ventricular hypertrophy are common findings.

Conclusions:

• Feline restrictive cardiomyopathy associated with endomyocardial fibrosis presents with distinct clinicopathologic and histopathologic features.
• The condition is characterized by significant endocardial scarring, left atrial enlargement, and potential hemodynamic compromise.