Autonomic nervous system response to L-dopa in patients with advanced Parkinson's disease.

Levodopa is the main treatment method for reducing the symptoms of Parkinson's disease. Whereas it reduces the motor symptoms efficiently, its effect on autonomous nervous system is not clear. The information about effect of levodopa on heart rate variability is not coherent between the studies. In this study, ECG of 11 patients with Parkinson's disease was measured during levodopa challenge with pronounced dose of fast release levodopa to ensure the positive drug effect for deep brain stimulation treatment. Heart rate variability analysis was done at three time points, before administration of levodopa, 30 and 60 minutes after administration. After 30 minutes of administration, the HRV parameters show that parasympathetic nervous system activity is decreased and the sympatho-vagal balance is shifted towards sympathetic control. At 60 minutes after administration the parasympathetic nervous system activates slightly and causes a decrease in heart rate.