A system and method for creating lesions and assessing their completeness or transmurality. Assessment of transmurality of a lesion is accomplished by monitoring the depolarization signal in a local electrogram taken using electrodes located adjacent the tissue to be ablated. Following onset of application...http://www.google.ca/patents/US7824399?utm_source=gb-gplus-sharePatent US7824399 - Ablation system and method of use