- Subjects with a known contraindication for insertion of the TEE probe (e.g. history of esophageal stricture, scleroderma, etc.), which will be ascertained by a non-invasive imaging specialist (contraindications are routinely assessed in the course of the preoperative workup)Subjects who have a known contraindication for insertion of the TEE probe (e.g. history of esophageal stricture, scleroderma, etc.), which will be ascertained by a non-invasive imaging specialist (contraindications are routinely assessed in the course of the preoperative workup)