A system for treating a passageway within a body comprising: a catheter comprising a first electrode and at least one additional electrode disposed at a distal end of the catheter, wherein the distal end of the catheter is configured to be positioned within the passageway so that the first electrode and the at least one additional electrode are able to transmit pulsed electric field energy to an inner circumference of the passageway; and a generator in electrical communication with the first electrode and the at least one additional electrode, wherein the generator includes at least one energy delivery algorithm configured to provide the pulsed electric field energy to the first electrode and the at least one additional electrode in a pattern comprising a plurality of phases spaced in time, wherein the plurality of phases comprises a) a first phase wherein the at least one energy delivery algorithm is configured to: provide the pulsed electric field energy to the first electrode so as to prioritize energy delivery through the first electrode to begin creating a first treatment area; and then switch to individually provide the pulsed electric field energy to the at least one additional electrode so as to prioritize energy delivery through the at least one additional electrode so as to at least begin creating an additional treatment area corresponding to the at least one additional electrode, and b) at least one additional phase wherein the at least one energy delivery algorithm is configured to provide the pulsed electric field energy to the first electrode so as to prioritize energy delivery through the first electrode to continue or finish creating the first treatment area, wherein the first phase and the at least one additional phase are spaced in time so that the cells receiving the pulsed electric field energy gradually culminate in cell death at a rate utilizing less energy than would occur if the pulsed electric field energy were delivered continuously from the creation to completion of the first treatment area, wherein the first treatment area and the additional treatment areas extend along the inner circumference of the passageway so as to create a functionally continuous treatment area spanning the inner circumference. a catheter comprising a first electrode and at least one additional electrode disposed at a distal end of the catheter, wherein the distal end of the catheter is configured to be positioned within the passageway so that the first electrode and the at least one additional electrode are able to transmit pulsed electric field energy to an inner circumference of the passageway; and a generator in electrical communication with the first electrode and the at least one additional electrode, wherein the generator includes at least one energy delivery algorithm configured to provide the pulsed electric field energy to the first electrode and the at least one additional electrode in a pattern comprising a plurality of phases spaced in time, wherein the plurality of phases comprises a) a first phase wherein the at least one energy delivery algorithm is configured to: provide the pulsed electric field energy to the first electrode so as to prioritize energy delivery through the first electrode to begin creating a first treatment area; and then switch to individually provide the pulsed electric field energy to the at least one additional electrode so as to prioritize energy delivery through the at least one additional electrode so as to at least begin creating an additional treatment area corresponding to the at least one additional electrode, and b) at least one additional phase wherein the at least one energy delivery algorithm is configured to provide the pulsed electric field energy to the first electrode so as to prioritize energy delivery through the first electrode to continue or finish creating the first treatment area, a) a first phase wherein the at least one energy delivery algorithm is configured to: provide the pulsed electric field energy to the first electrode so as to prioritize energy delivery through the first electrode to begin creating a first treatment area; and then switch to individually provide the pulsed electric field energy to the at least one additional electrode so as to prioritize energy delivery through the at least one additional electrode so as to at least begin creating an additional treatment area corresponding to the at least one additional electrode, and b) at least one additional phase wherein the at least one energy delivery algorithm is configured to provide the pulsed electric field energy to the first electrode so as to prioritize energy delivery through the first electrode to continue or finish creating the first treatment area, wherein the first phase and the at least one additional phase are spaced in time so that the cells receiving the pulsed electric field energy gradually culminate in cell death at a rate utilizing less energy than would occur if the pulsed electric field energy were delivered continuously from the creation to completion of the first treatment area, wherein the first treatment area and the additional treatment areas extend along the inner circumference of the passageway so as to create a functionally continuous treatment area spanning the inner circumference.