Original investigation of right-to-left shunting patent ductus arteriosus in an Irish setter puppy.

A six-month-old, entire female, Irish setter was presented with a two-month history of progressive hindlimb weakness and collapse on exercise. Thoracic auscultation revealed a soft systolic murmur and a split second heart sound. Differential cyanosis and polycythaemia were not observed. Right-to-left shunting patent ductus arteriosus (r-PDA) was confirmed on contrast echocardiography ("bubble study") and selective right ventricular angiography. Comparison of blood gases from the metatarsal and auricular artery confirmed the presence of differential hypoxia. This technique is not known to have been described previously in the diagnostic investigation of r-PDA in dogs.