An electrical ablation device may generally comprise first and second electrodes coupled to an energy source operative to generate and deliver a first sequence of electrical pulses and a second sequence of electrical pulses to tissue having a necrotic threshold, wherein the first sequence of electrical pulses delivers a first energy dose that is less than the necrotic threshold to induce thermal heating in the tissue and the second sequence of electrical pulses delivers a second energy dose equal to or greater than the necrotic threshold to induce cell necrosis in the tissue by irreversible electroporation. The first sequence of electrical pulses may each be independently characterized by a first amplitude, a first pulse width, and a first frequency. The second sequence of electrical pulses may be characterized by a second amplitude, a second pulse width, and a second frequency.
