Background: Restrictive cardiomyopathy (RCM) is an uncommon but clinically significant myocardial disease in feline patients. It is characterized by impaired ventricular diastolic filling due to increased myocardial stiffness, while systolic performance remains generally preserved. Unlike hypertrophic or dilated cardiomyopathies,
RCM is associated with biatrial enlargement and a restrictive Doppler profile, often progressing to right-sided congestive heart failure. Echocardiography plays a crucial role in providing structural and functional insights. Methods: A ۱۲-year-old domestic shorthair cat was presented to Ghoghnoos pet hospital and examined by comprehensive echocardiography, including two-dimensional, M-mode, Doppler, and strain imaging. Atrial and ventricular dimensions, measurements, diastolic filling indices, and valvular function were also recorded. Results: Echocardiography demonstrated severe left atrium dilation (LA/Ao ratio: ۲.۵۱) and moderate-to-severe right atrial enlargement, with thin atrial walls and no evidence of thrombus. The left ventricle showed normal to slightly reduced internal dimensions, increased endocardial echogenicity, and preserved systolic function. The right ventricle illustrated mild concentric hypertrophy and adequate systolic function. Strain imaging revealed a “bull’s-eye” pattern with reduced deformation in basal and mid-segments, consistent with RCM. Marked mitral and tricuspid regurgitation were observed, contributing to significant atrial volume overload. Indirect indicators of pulmonary hypertension included increased tricuspid regurgitant velocity, interventricular septum flattening, and right atrium enlargement. A small pericardial and pleural effusion, along with ascites, reflected advanced right-sided congestive heart failure. Doppler analysis demonstrated an increased E/A ratio, shortened deceleration time, and reduced IVRT, consistent with restrictive diastolic dysfunction. Additional findings included moderate degrees of aortic and pulmonic insufficiency. Conclusion: This case illustrates advanced
RCM in a feline patient, marked by severe biatrial enlargement, impaired diastolic filling, preserved systolic function, and significant valvular insufficiencies. Early and precise echocardiographic assessment, incorporating both strain and Doppler imaging, is essential for the diagnosis and management of feline cardiomyopathies.