A transient hypotensive episode (Bezold-Jarisch effect) occurring in a patient treated with microwave hyperthermia.

A case report of a hypotensive episode occurring during a microwave hyperthermia treatment is reported. Microwave hyperthermia was delivered using 915 MHz externally applied energy. The tumor being treated was either a superficial lymph node or local recurrence in the subdigastric region overlying the carotid artery. During the patient's treatment, she reported symptomatology consistent with a neuropathy which is characterized by its association with microwave energy. As the treatment progressed the patient developed syncopy, hypotension, and bradycardia similar to a Bezold-Jarisch reflex. All of these conditions promptly self-corrected when the microwave energy was discontinued. This event can be explained by a transient microwave induced neuropathy specifically involving the carotid body or sinus.