<prompt> On increasing vagal tone following occurs in pacemakerIncreased K increased slopDecreased K decreased slopIncreased K decreased slopDecreased K increased slop  <response>: When the cholinergic vagal fibers to nodal tissue are stimulated, the membrane becomes hyperpolarizedThe slope of the prepotentials is decreased because the acetylcholine released at the nerve endings increases the K conductance of nodal tissue.Which cause rapid efflux of KRef: Ganongs Review of Medical Physiology Twenty-Third Edition Page No: 491 