The German shepherd dog with a PDA, below, has been shaved and marked to show the locations of the fifth rib (panel B), the mitral valve area (panel C), and the aortic/pulmonic valve area (panel D).

pda6	pda6a-n Location of the fifth rib
pda6b-n Location of the mitral valve region	pda6c-n Location of the aorto-pulmonary region

Auscultatory findings in dogs with PDA

These are the phonocardiogram (top tracing) and electrocardiogram (bottom tracing) from the mitral valve area of a dog with PDA. The phonocardiogram shows the first and second heart sounds, which are normal in this case. No murmur is recorded in this location. Dogs with a larger patent ductus arteriosus may have a systolic or continuous murmur in the mitral area.

pda7

These are the phonocardiogram (top tracing) and electrocardiogram (bottom tracing) from the aortic/ pulmonic valve area of a dog with PDA. The phonocardiogram is abnormal and shows the continuous "machinery murmur" characteristic of animals with PDA.

pda8

Radiographic findings in dogs with PDA 

Below is a lateral radiograph from a 6-year-old female dog with PDA. It shows enlargement of the left heart and increased pulmonary vascular markings. The right apical artery and right apical vein are particularly prominent and both exceed the smallest diameter of the 4th rib indicating overcirculation in the lungs.

pda9 Panel A. Lateral radiograph of a dog with PDA	pda9a Panel B. Yellow shading highlights the large left ventricular silhouette
pda9b Panel C. The shaded area highlights the increased pulmonary vascular markings	pda9c Panel D. The yellow line highlights the cranial lobar artery
pda9d Panel E. The yellow line highlights the cranial lobar vein	pda9e Panel F. The yellow line highlights the 4th rib.

The dorsoventral radiograph, below, shows a ductal-aortic aneurysm manifesting as a leftward bulge in the descending aorta, which is a characteristic sign of a moderate-to-large PDA.

pda10 Panel A. Dorsoventral view of a dog with a large PDA.

pda10a Panel B. The arrows highlight the "ductus bump" (ductal aneurysm).