Bain Bridge reflex causes:

A Bainbridge Reflex is a positive feedback mechanism in which there is a compensatory increase in hea rate, due to a rise in right atrial pressure. It is commonly referred to as an Atrial Reflex. Bainbridge reflex, or atrial reflex: is an acceleration of the hea rate resulting from increased blood pressure in, or increased distension of, the large systemic veins and the right upper chamber of the hea. Atrial stretch receptors are responsible for this. Afferent signals: are carried through the vagus nerves to the medulla of the brain. Efferent signals are transmitted back through vagal and sympathetic nerves to increase hea rate and strength of hea contraction. Prevents damming of blood in the veins atria and pulmonary circulation. The reflex competes with the baroreceptor-mediated decrease in hea rate produced by volume expansion and is diminished or absent when the initial hea rate is high. Bain bridge Reflex can be eliminated by transection of the cardiac autonomic nerve supply and injection of atropine. A "reverse" Bainbridge reflex has been proposed to explain the decreases in hea rate observed under conditions in which venous return is reduced, such as during spinal and epidural anesthesia, controlled hypotension, and severe hemorrhage. Ref: Complications in anesthesiology, edited by Emilio B. Lobato, M.D., Nikolaus Gravenstein, Robe R. Kirb,Page 300; Essentials Of Medical Physiology, By Khurana,Page 198.