<prompt> All are effects of sympathetic stimulation exceptIncreased conduction velocityIncreased hea rateIncreased refractory periodIncreaed contractility of hea  <response>: Stimulation of the sympathetic cardiac nerves speeds the depolarizating effect of IH and the rate of spontaneous discharge increasesThis is possible by decrease in the refractory period Ref: Ganongs Review of Medical Physiology Twenty-Third Edition Page No:492 