Real-time three-dimensional evaluation of the feline heart; feasibility and reference intervals

Abstract

Current feline echocardiographic practice relies on linear, geometry-dependent two-dimensional and Motion mode (M-mode) measures rather than direct volumetric quantification. Full-volume real-time three-dimensional echocardiography (RT3DE) can produce ventricular volumes without the geometric assumptions of two-dimensional methods, but its feasibility and normal values have not been established for the feline left ventricle. This prospective, cross-sectional study evaluated the feasibility of full-volume RT3DE and generated reference intervals for left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) in 120 healthy cats. Diagnostic-quality datasets were obtained in all cats, the majority without sedation, and three-dimensional acquisition time was significantly shorter than that of the conventional two-dimensional examination. EDV was weakly associated with body weight and is reported as weight-specific allometric limits, whereas ESV and EF were independent of body weight. Interobserver reproducibility was strongest for ejection fraction and weakest for end-systolic volume. These findings demonstrate that full-volume RT3DE is feasible in healthy cats and provide preliminary normative values that may support volumetric assessment of feline cardiac disease. The reference intervals were derived from clinically healthy cats and require validation before application to cats with suspected cardiomyopathy.