There is disclosed how complete or partial submersion of one or both of the jaws of an ablation device in a fluid may be detected prior, during or following an ablation procedure. Submersion sensors may be incorporated into the jaws of an ablation device and can be used to determine if the electrodes are fully submerged, partially submerged, or are in a state of oscillation between submersion and non-submersion. There is also disclosed a system and method for creating lesions and assessing their completeness or transmurality. Assessment of transmurality of a lesion is accomplished by monitoring the impedance of the tissue to be ablated.
