Both the Phase I and Phase II studies will be open label. An open label study design is proposed because it is not possible to blind the clinicians, patients or the sponsor to the identity of the diagnostic technique in Phase I (ICE vs. TEE) and to management strategy in Phase II (ICE vs. Conventional Strategy). The ICE and TEE data analysis in the Phase I component by the core lab will be blinded in so far as the identity of the patient, investigator and center. In the Phase II study, patient randomization to the treatment groups will minimize the chance of patient selection bias. An 8-week study duration was chosen for the Phase II component because most major cardiac and bleeding complications occur within this period.