Nicoladoni sign is positive in a young patient with an aeriovenous fistula. This sign is also known as:

Nicoladoni-Branham sign: Compression of a large aeriovenous fistula may cause reflex slowing of the hea rate. Duplex ultrasonography may detect an aeriovenous fistula, especially one that affects the femoral aery and vein at the site of catheter access. Computed tomographic and conventional angiography can confirm the diagnosis. Ref: Creager M.A., Loscalzo J. (2012). Chapter 249. Vascular Diseases of the Extremities. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.