CARDIOVASCULAR SYSTEM
The heart is in the midline and is in contact with the thoracic wall at ribs 3-5 (Bivin et al. 1987). The heart rate can vary from 250 to 500 beats per minute. There are three main branches arising from the aortic arch (innominate, left common carotid, and left subclavian), and three caval veins (two cranial vena cavae and one caudal vena cava) enter the right atrium.
As in the rat, the pulmonary veins contain sheaths of cardiac muscle fibers within the vessel walls (Bivin et al. 1987; Magalhaes 1968).Venepuncture
The blood volume of the Syrian hamster is about 78 ml/kg (Bivin et al. 1987). Due to lack of a tail, vein blood sampling can be difficult, but the saphenous or jugular veins can be tried (McClure 1999). Laboratory animals are often bled via the orbital venous sinus and cardiac puncture, but this is not recommended in pet animals (Whittaker 1999). Hamsters have a rapid coagulation time so heparin may need to be used.