An RF electrode can have a straight shaft to generate an RF heat lesion that is asymmetric about the central axis of the cannula through which the RF electrode is introduced into bodily tissue. For example, a system for tissue ablation can include a cannula and an electrode, the cannula including an elongated shaft having a proximal end and a distal end, the cannula shaft including an electrically conductive active tip distal to an electrically insulated cannula shaft portion, the cannula shaft including a lumen extending from a proximal opening at the proximal end of the shaft to an exit opening within a distal portion of the cannula shaft, the electrode including an electrode shaft having a proximal end and a distal end, the electrode shaft including an electrically conductive active tip distal to an electrically insulated electrode shaft portion.
