Radiographic cardiac size in cats and dogs with heartworm disease compared with reference values using the vertebral heart scale method: 53 cases

Heartworm-infected cats and dogs often have an enlarged cardiac silhouette on thoracic radiographs. The VHS method, measurement of the caudal vena cava expressed in vertebral lengths, and the calculation of the ratio of the right pulmonary or caudal lobar artery width to rib 9 width are all useful tools to monitor the natural history of the disease and aid in staging for therapy of heartworm disease.