Electrophysiologic measure of endpoints for ablation lesions created in fibrillating substrates

The present invention is related to cardiac ablation treatments. 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.