transesophageal echocardiogram

TEE involves passing an ultrasound transducer mounted on an endoscope-like probe into the esophagus, placing it in close proximity to the posterior cardiac structures without interference from lung tissue or chest wall, thus providing superior image resolution compared to TTE. Clinical indications include: evaluation for left atrial appendage thrombus prior to cardioversion or ablation in atrial fibrillation (since TTE has poor sensitivity for LAA clots); diagnosis of infective endocarditis, especially when TTE is nondiagnostic or prosthetic valve endocarditis is suspected; evaluation of aortic dissection (high sensitivity/specificity, especially for Type A); assessment of prosthetic valve function and paravalvular abscess; intraoperative guidance during valve repair/replacement surgery; evaluation of cardiac source of embolism (patent foramen ovale, atrial septal defect, atrial masses); and assessment of mitral valve pathology before surgical repair. Contraindications include esophageal strictures, varices, diverticula, recent esophageal surgery, and significant GI bleeding. Risks are uncommon but include esophageal perforation, bleeding, and aspiration; the procedure typically requires sedation and sometimes general anesthesia. TEE is often performed under moderate sedation with topical anesthesia to the oropharynx to suppress the gag reflex. Compared to TTE, TEE avoids attenuation from ribs, lungs, and chest wall, offering superior views of the left atrium, atrial septum, mitral valve, thoracic aorta, and prosthetic valves, but is more invasive and requires sedation.