Visit-to-Visit Blood Pressure Variability Are Associated with an Imbalance between Sympathetic and Parasympathetic Tone in Hypertensive Patients

Greater fluctuations in office blood pressure increase the risk of stroke and blood pressure volatility is an important risk factor for cardiovascular events. Effects of sympathetic and parasympathetic nerve on blood pressure regulation are well known, however, those on visit-to visit variation remains unclear. Aim of this study is to clarify the contribution of sympathetic and parasympathetic balance on blood pressure fluctuation. Methods: We enrolled 23 outpatients with essential hypertension. We measured blood pressure, and pulse rate at clinic 14 times in a row and calculated coefficient of variance (CV) as visit-to-visit variability. The velocity of pupil contraction, miosis (VC) and dilation, mydriasis (VD) was determined from pupillary function test. Results: Systolic blood pressure and diastolic blood pressure were not significantly correlated with VC, VD and VD/VC. Heart rate was not correlated with VC and VD, but significantly correlated with VD/VC. CV of systolic blood pressure, diastolic blood pressure and heart rate were not significantly correlated with VC or VD. Ratio of VD to VC significantly negative correlated with CV of blood pressure, diastolic blood pressure, and heart. Value of VD was significantly correlated with value of VC. Conclusion: Visit-to-visit variability of blood pressure and heart rate is not related with sympathetic or parasympathetic tone independently but augmented by the impaired sympathetic and parasympathetic balance.