Baroreflex failure following radiation therapy for nasopharyngeal carcinoma

The authors present a 51-year-old man with right-sided nasopharyngeal carci noma who was treated for regional lymph node involvement by bilateral radia tion therapy of the neck. Six years later he presented with episodic compla ints of headache, flushing, and palpitations accompanied by elevations of b lood pressure. Examination of arterial baroreflex function indicated select ive afferent carotid sinus denervation. Cross spectral analysis of spontane ous heart rate and blood pressure variability showed decreased arterial bar oreflex sensitivity (6.5 ms/mm Hg). Twenty-foul hour measurements of blood pressure and heart rate variability showed labile hypertension during norma l daytime activities. Baroreflex failure in this patient probably represent s a late complication of bilateral radiation therapy of the neck.