This study compares two small animal models for inducing volume-overload heart failure using arterio-venous shunts in different locations (aorto-caval and femoral) in rats. The research involved 28 female Sprague-Dawley rats, divided into three groups, with surgeries performed to create the shunts. The aorto-caval model had shorter surgery times but higher complication rates, including significant bleeding, while the femoral model showed a significant increase in blood flow post-surgery. Echocardiography revealed heart failure progression in both operated groups, with the aorto-caval group showing more severe symptoms. However, the femoral arterio-venous shunt model was deemed more favorable due to better standardization, fewer complications, and more consistent results.