Abstract: This article reports a case of a 66-year-old female patient with hypertrophic obstructive cardiomyopathy who underwent thoracoscopic left upper lobectomy under continuous intraoperative transesophageal echocardiography (TEE) monitoring.The preoperative left ventricular outflow tract gradient was 65 mm Hg.Intraoperative TEE provided real-time monitoring of left ventricular volume, outflow tract velocity, and mitral valve motion, guiding anesthesia induction, fluid management, and the use of vasoactive agents.Inotropic drugs were avoided to maintain hemodynamic stability.The patient recovered smoothly postoperatively without cardiac complications.

Key words: transesophageal echocardiography, hypertrophic obstructive cardiomyopathy, one-lung ventilation, lung cancer radical surgery, real-time monitoring