Journal international de neuroréadaptation

The Effect of Viagra on Autonomic Function Using Spectral Analysis and Approximate Entropy Method

Abstract

Ahmed Kamal

Objective: Autonomic nervous system involvement in patients with Erectile Dysfunction (ED) has shown conflicting results. Our main purpose was to assess the effect of treatment with Viagra on autonomic function of group of ED patients in comparison with another group with control subjects with ED treated by herbal substances by measuring the frequency gain response of the two groups. Other aim of this study was to determine wither the duration of Viagra treatment correlated with measures of heart rate variability signal (HRV) using approximate entropy index (ApEn).
Methods: Twenty two patients treated for ED by Viagra (100 mg) and twenty one matched control subjects treated ED by herbal were evaluated at Erectile Dysfunction Center, Johns Hopkins Hospital, Maryland, USA during 2012/ 2013 by measuring the breathing at different rates and HRV signal derived from Electrocardiogram (ECG).The autopower and cross power spectra between HRV signal and breathing signal at different breathing rate were calculated and frequency gain response for both groups were obtained. ApEn described as measure of regularity of HRV was calculated for both patients with Viagra treatment and herbal treatment for control subjects.
Results: Both frequencies gain response and ApEn measures were increased in patients treated with Viagra in comparison with control group. The power spectra of patients with Viagra men showed both increase High Frequency (HF) value and higher low frequency bands with respect to control subjects. On other hand, ApEn measure was significantly increased in longer Viagra taking duration than in herbal group.
Conclusion: These findings suggest that the spectral analysis of HRV signal using breathing at different frequencies may detect balance of autonomic of autonomic system of ED patients treated with Viagra specially with increasing the sympathetic activity (higher low frequency) and as well as the parasympathetic tone(higher frequency gain response) which can lead to reduce sudden deaths in patients with treating with viagra. APEn may be marker related to duration of taking Viagra. Further studies are needed to include more patients to strengthen the quantitive and qualitative indices proposed in this paper.