Cardiac Autonomic Neuropathy and Complications of Primary Hypertension: Is Autonomic Neuropathy a Cause or a Result?

OBJECTIVE: Cardiac autonomic dysfunction (COD) is one of the important factors implicated in the pathogenesis of primary hypertension (HT). Heart rate variability (HRV) measurement has been used widely to determine the COD. We aimed to examine the HRV in primary hypertension and its relationships with end organ damage. MATERIAL and METHODS: Ninety adult patients and 28 healthy controls were included into the study. Heart rates (HRs) and HRV parameters were measured by monitoring with 24-hour Holter electrocardiographic records. Patients were assessed in terms of retinopathy, microalbuminuria and left ventricle hypertrophy. RESULTS: Primary hypertensive patients had significantly higher blood pressure (BP) values than those of the controls. Minimum HRs of all patients were significantly higher than controls, while HRV parameters showed significantly lower values in the patients compared to controls. The HRV parameters showed no significant correlations with retinopathy, left ventricle hypertrophy, microalbuminuria and cardiovascular risk factors. CONCLUSION: Lower HRV parameters in hypertensive patients probably suggests the presence of a COD. However, such a difference was not observed between the newly and previously diagnosed patients indicating that the HRV seems not to be influenced by antihypertensive treatment.