[Carotid baroreflex in sleep apnea patients]

15 patients (11 male, 9 female) with obstructive sleep apnoea syndrome (OSAS) and 10 healthy age- and weight-matched control subjects volunteered to participate in the study to test circadian variations of cardiac response to activation of carotid baroreceptors. Activation of carotid baroreceptors was evoked by applying a negative pressure to both left and right carotid sinus regions, using two small separate neck-suction capsules. All experiments were performed under standard conditions every two hours. The cardiac response to carotid baroreceptors activation was significantly reduced in OSAS Patients, to a greater degree in the group of hypertensive patients. A characteristic circadian rhythm of baroreceptor reactivity persisted in all OSAS patients. Thus, OSAS patients constitute a high-risk group for the development of cardiovascular diseases and pathological course of blood pressure during daytime.