Electrophysiologic measure of endpoints for ablation lesions created in fibrillating substrates

Methods, systems, and computer program products measure electrical activity of the cardiac tissue proximate the lesion site during an ablation treatment, and then compare the measurements to determine whether the lesion is clinically efficacious so as to be able to block myocardial propagation. The methods can include obtaining the measurements and performing the ablation therapy while the subject is experiencing atrial fibrillation and may measure the standard deviation of the electrogram signal. Certain of the methods and systems measure the electrical activity at multiple sites about the lesion site to detect whether the lesion is uniformly or sufficiently transmural about its length (and through the thickness of the wall).