Exemplary methods for affecting conduction and/or operation of the AV node and/or AV bundle. Various exemplary methods include delivery of one or more stimulation pulses to affect conduction and/or operation of an AV node and/or AV bundle. Such delivery optionally stimulates nerves and/or tissue. Nerve stimulation optionally includes parasympathetic nerve stimulation to decrease conduction of the AV node and/or AV bundle. Tissue stimulation optionally causes tissue to enter a refractory period. Various exemplary methods include delivering one or more stimulation pulses during postinspiration. Other exemplary methods and/or devices are also disclosed.