a, During cardiac fibrillation, the pre-shock electrical state of the heart (the transmembrane potential throughout the heart; Vm,pre) features numerous unstable, electrical rotating waves (rotor waves). b, Traditional defibrillation works to rapidly bring the post-shock state (Vm,post) to resting levels by means of a single, large electrical shock. c, Luther et al.3 describe low-energy antifibrillation pacing (LEAP), in which multiple low-strength shocks are applied to generate many virtual electrodes across the heart. These virtual electrodes excite the heart tissue, and the waves generated by each pulse of electricity propagate away from the electrodes, interacting with the rotor waves to eventually terminate fibrillation.
Life-threatening abnormalities in the electrical rhythm of the heart are usually treated with the application of a large electric shock. An approach involving a significantly smaller shock energy may be equally effective.