Unexpected Systolic Anterior Motion of the Mitral Valve Diagnosed by Transthoracic Echocardiography after the Induction of General Anesthesia.

We report an 87-year-old woman who presented with unexpected systolic anterior motion (SAM) of the mitral valve after the induction of general anesthesia. She was receiving medication for hypertension and cerebral infarction. There were no abnormal findings on her preoperative transthoracic echocardiography (TTE) examination. After the induction of general anesthesia, she presented with refractory hypotension. We performed TTE and diagnosed SAM of the mitral valve. Her hemodynamic state was improved by fluid infusion and administering intravenous phenylephrine. After the surgery, we performed a morphologic assessment of the patient's heart using TTE. We found a thick basal interventricular septum and a small distance from the mitral coaptation point. to the septum. This case shows that SAM of the mitral valve can occur in a patient without preoperative cardiac abnormalities. SAM of the mitral valve should be considered in the differential diagnosis of refractory hypotension, particularly in elderly patients. Perioperative TTE is a useful tool for the rapid diagnosis and treatment of hemodynamic instability.