Impairment of parasympathetic baroreflex responses in migraine patients

Objectives - The aim of this study was to assess baroreflex regulation of the heart rate and blood vessels in migraine patients in comparison with healthy controls. Methods - In 30 migraine patients who were in a headache-free phase, aged 34 ± 2 years, and 30 healthy controls, aged 34 ± 3 years, we applied oscillatory neck suction at 0.1 Hz to assess the sympathetic modulation of the heart and blood vessels and at 0.2 Hz to assess the effect of parasympathetic stimulation on the heart. Breathing was paced at 0.25 Hz. Electrocardiographic RR-intervals, blood pressure and respiration were continuously recorded. Responses to the baroreflex stimulations were assessed as the changes in power of the RR-interval and blood pressure fluctuations at the relevant stimulating frequency from the baseline values. Results - Systolic and diastolic blood pressure responses to the 0.1 Hz neck suction pressure were not significantly different between the patients and controls. The RR-interval oscillatory response to 0.2 Hz neck suction was significantly less (P < 0.05) in the migraine patients (4.45 ± 0.27 In ms) compared with the controls (5.48 ± 0.36 In ms²). Conclusion - These results suggest that baroreflex-mediated cardiovagal responses are reduced in migraine patients. However, the sympathetic-mediated baroreflex control of the blood vessels is intact in the migraine patients. The autonomic nervous system may have a role in the pathophysiology of migraine.