Frantz S; Lührs H;
Allolio B; Koller ML
Medizinische Universitätsklinik
Würzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany. s.frantz@mail.uni.wuerzburg.de
The baroreflex
mechanism is a central part of the regulation of the cardiovascular system,
particularly in the control of vagal and sympathetic outflow to the heart and
the peripheral circulation. Failure of the baroreflex
is a rare cause of secondary hypertension. It is characterized by drastic
changes in sympathetic activation and blood pressure following complete
denervation of the baroreflex. Here, we report a case
of baroreflex failure following bilateral carotid
artery surgery and radiation. Moreover, postoperative orthostatic hypotension
with recurrent syncope suggests a rare subform, the
selective baroreflex failure, where efferent
parasympathetic activity is preserved. Both high blood pressure and orthostatically induced syncope improved substantially
after treatment with clonidine.