Combined cardiac sympathetic excitation and vagal impairment in patients with non-organic erectile dysfunction.
ABSTRACT Patients with non-organic erectile dysfunction (ED) frequently present with syndromes involving systemic sympathovagal dysfunction. The linkage of ED to cardiac autonomic regulation is not well understood.
Forty-four men with non-organic ED and 38 healthy age-matched control subjects with ages ranging from 40 years to 69 years were recruited. These two groups were divided into three distinct age categories at 10-year intervals. Patients were divided into three different severity categories, among whom 35 patients received a two-month oral treatment of trazodone. Power spectral analysis of successive R-R intervals (RR) was performed to evaluate the variance (variance of RR-interval values), the high-frequency power (HF), and the ratio of low-frequency power to HF (LF/HF) of their heart rate variability (HRV).
Patients exhibited a significantly lower variance and HF, but a higher LF/HF compared to the control group across all age categories. The changes in variance and HF were severity dependent. In addition, all the HRV parameters of the patients with a satisfactory response after treatment have significantly improved.
The results indicate that patients with non-organic ED had significant cardiac sympathetic hyperactivity and severity-dependent cardiac vagal impairment.
Non-organic ED may be accompanied by an abnormality in cardiac autonomic regulation.
- [show abstract] [hide abstract]
ABSTRACT: Transneuronal tracing techniques were used in order to identify putative spinal interneurons and brainstem sites involved in the control of penile function. Pseudorabies virus was injected into the corpus cavernosus tissue of the penis in rats. After a four day survival period, rats were perfused with fixative and virus-labelled neurons were identified by immunohistochemistry. Postganglionic neurons were retrogradely labelled in the major pelvic ganglia. In the spinal cord, sympathetic and parasympathetic preganglionic neurons were labelled transneuronally. Presumptive interneurons were also labelled in the lower thoracic and lumbosacral spinal cord in locations consistent with what is currently known about such interneurons. In the brainstem, transneuronally labelled neurons were found in the medulla, pons and hypothalamus. Regions consistently labelled included the nucleus paragigantocellularis, parapyramidal reticular formation of the medulla, raphe pallidus, raphe magnus, A5 noradrenergic cell group, Barrington's nucleus and the paraventricular nucleus of the hypothalamus. This study confirmed previous studies from our lab and others concerning the preganglionic and postganglionic neurons innervating the penis. The number, morphology and location of these neurons were consistent with labelling seen following injection of conventional tracers into the penis. The brainstem nuclei labelled in this study were also consistent with what is currently known about the brainstem control of penile function. The labelling appeared to be highly specific, in that descending systems involved in other functions were not labelled. These results provide further evidence that the pseudorabies virus transneuronal tracing technique is a valuable method for identifying neural circuits mediating specific functions.Neuroscience 08/1993; 55(1):263-80. · 3.12 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: The purpose of this research was to determine the prevalence of erectile dysfunction (ED) in a non-selected population using the abridged 5-item version of the International Index of Erectile Function (IIEF-5) as a diagnostic tool. In a non-institutionalized population and during a free screening program for prostate cancer (Prostate Cancer Awareness Week of Santa Casa Hospital, Porto Alegre, Brazil), from 26 to 30 July 1998, all men who were attending were invited to complete a sexual activity questionnaire (the abridged 5-item version of the International Index of Erectile Function-IIEF-5) as a diagnostic tool for ED. The possible scores for the IIEF-5 range from 5 to 25, and ED was classified into five categories based on the scores: severe (5-7), moderate (8-11), mild to moderate (12-16), mild (17-21), and no ED (22-25). Of the 1071 men who participated in the program, 965 (90.1%) were included in this study. Of the responding men 850 were Caucasian (88%) and 115 were black (12%). The mean age of the men was 60.7 y, ranging from 40 to 90 y old. In this sample the prevalence of all degrees of ED was estimated as 53.9%. In this group of men, the degree of ED was mild in 21.5%, mild to moderate in 14.1%, moderate in 6.3%, and severe in 11.9%. According to age the rates of ED were: 40-49 (36.4%); 50-59 (42.5%); 60-69 (58.1%); 70-79 (79.4%), and over 80 y (100%) showed ED (P<0.05). The Pearson coefficients between the variables age and IIEF-5 showed a statistically significant inverse (negative) relation (r=-0.3449; P<0.05). ED is highly prevalent in men over 40 and this condition showed a clear relationship to aging, as demonstrated in other studies published. The simplified IIEF-5, as a diagnostic tool, showed to be an easy method, which can be used to evaluate this condition in studies with a great number of men.International Journal of Impotence Research 08/2002; 14(4):245-50. · 1.51 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Drugs acting within the central nervous system (CNS) that reduce the sympathetic antierectile flow and enhance the parasympathetic proerectile flow to the penis may restore penile erection in cases of erectile dysfunction of both psychogenic and organic origin. The best characterized of such drugs is the dopaminergic agonist apomorphine, which acts on the hypothalamus and, perhaps, the autonomic nuclei in the spinal cord. Other drugs that target the CNS and have been registered and tested are the a(2)-adrenoceptor antagonists yohimbine and delequamine, the alpha-melanocyte-stimulating hormone agonist melanotan II, and the serotonin reuptake inhibitor trazodone. Androgens also may influence sexual behavior by acting within the CNS, notably by modifying the neurotransmitter system targeted by these drugs. Our knowledge of the mode of action of CNS drugs comes mainly from experiments on rodents. Consequently, explanations regarding the way they work in humans are only speculative.Current Urology Reports 01/2002; 2(6):488-94.
Combined cardiac sympathetic excitation and vagal impairment in patients
with non-organic erectile dysfunction
Chih J. Chena,b,1, Terry B.J. Kuoc,d,e,1, Yi-Jhan Tsengb, Cheryl C.H. Yangc,d,e,*
aDepartment of Urology, Hualien General Hospital, Department of Health, Executive Yuan, Taiwan
bInstitute of Neuroscience, Tzu Chi University, Hualien, Taiwan
cInstitute of Brain Science, National Yang-Ming University, No. 155, Linong Street, Sec. 2, Taipei 11221, Taiwan
dDepartment of Education and Research, Taipei City Hospital, Taipei, Taiwan
eSleep Research Center, National Yang-Ming University, Taipei, Taiwan
a r t i c l ei n f o
Accepted 10 October 2008
Available online 19 December 2008
Heart rate variability
Non-organic erectile dysfunction
a b s t r a c t
Objective: Patients with non-organic erectile dysfunction (ED) frequently present with syndromes involv-
ing systemic sympathovagal dysfunction. The linkage of ED to cardiac autonomic regulation is not well
Methods: Forty-four men with non-organic ED and 38 healthy age-matched control subjects with ages
ranging from 40 years to 69 years were recruited. These two groups were divided into three distinct
age categories at 10-year intervals. Patients were divided into three different severity categories, among
whom 35 patients received a two-month oral treatment of trazodone. Power spectral analysis of succes-
sive R-R intervals (RR) was performed to evaluate the variance (variance of RR-interval values), the high-
frequency power (HF), and the ratio of low-frequency power to HF (LF/HF) of their heart rate variability
Results: Patients exhibited a significantly lower variance and HF, but a higher LF/HF compared to the con-
trol group across all age categories. The changes in variance and HF were severity dependent. In addition,
all the HRV parameters of the patients with a satisfactory response after treatment have significantly
Conclusion: The results indicate that patients with non-organic ED had significant cardiac sympathetic
hyperactivity and severity-dependent cardiac vagal impairment.
Significance: Non-organic ED may be accompanied by an abnormality in cardiac autonomic regulation.
? 2008 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights
Data collected from the Massachusetts Male Aging Study in the
late 20th century in the United States showed that 52% of a male
population of 1290 with age ranging from 40 years to 70 years
had some degree of erectile dysfunction (ED). This study also pre-
dicted that the prevalence of this worldwide problem would prob-
ably increase from 152 million men in 1995 to 322 million men in
2025 (Feldman et al., 1994). ED is currently classified into organic
(25%), non-organic (25%) and mixed origin (45%) dysfunction (Lue,
2000). The etiologies of organic ED can be divided into the follow-
ing: vascular, endocrinal, penile disease, neurological and drug re-
lated. If an ED is unable to be explained by the organic etiologies, it
is considered non-organic (Lenzi et al., 2003). Patients with non-or-
ganic ED frequently present with various syndromes associated
with systemic sympathovagal dysfunction, including fatigue, gas-
trointestinal problems, heat/cold intolerance, reduced/excessive
sweating, shortness of breath and micturation dysfunction. Sym-
pathovagal dysfunction has long been suspected as playing a role
in non-organic ED. Surprisingly, clinical evidence for this is still
Power spectral analysis of heart rate variability (HRV) is a
sophisticated and noninvasive tool for the detection of the auto-
nomic regulation of the heart. It has been well established that
HRV can be categorized into high-frequency (HF) and low-fre-
quency (LF) power components, according to its oscillating fre-
quency and mechanism (Task Force of the European Society of
Cardiology and the North American Society of Pacing and Electro-
physiology, 1996). The HF component is modulated by respiratory
sinus arrhythmia, and is considered to represent a vagal control
of the heart rate (Fouad et al., 1984). Normalized LF (LF%), and
the ratio of LF to HF (LF/HF) are considered by some investigators
1388-2457/$34.00 ? 2008 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
* Corresponding author. Address: Institute of Brain Science, National Yang-Ming
University, No. 155, Linung Street, Sec. 2, Taipei 11221, Taiwan. Tel.: +886 2
8267058; fax: +886 2 8273123.
E-mail address: email@example.com (C.C.H. Yang).
1Both the authors were contributed equally to this work.
Clinical Neurophysiology 120 (2009) 348–352
Contents lists available at ScienceDirect
journal homepage: www.elsevier.com/locate/clinph
to mirror the sympathovagal balance or to reflect sympathetic
modulations (Malliani et al., 1991; Pagani et al., 1997). The stan-
dard procedure and interpretation of HRV analyses was defined in
1996 (Task Force of the European Society of Cardiology and the
North American Society of Pacing and Electrophysiology, 1996).
Our previous studies (Liu et al., 2003; Kuo and Yang, 2005; Kuo
et al., 1999) had demonstrated that gender, age, amount of sleep
and estrogen level have a significant effect on the autonomic con-
trol of heart rate. Using a similar methodology, the present study
aims to test the hypothesis that patients with non-organic ED
have a significant cardiac sympathovagal dysfunction. Further-
more, whether the autonomic dysfunction is severity dependent
and if the autonomic functions can be restored after satisfactory
treatment were also investigated.
2. Methods and materials
2.1. Study sample and experimental setup
The participants were recruited from our outpatient urology
clinics at Hualien General Hospital, Department of Health, Hua-
lien, Taiwan. All the subjects who had been diagnosed with or-
ganic ED or ED combined with diseases associated with a high
risk of ED, such as diabetes, hypertension, cardiovascular dis-
ease, cancer, neuropathy and psychiatric disorders, were ex-
cluded. Patients with other diseases that might affect HRV
were also excluded. Subjects who used drugs that have been re-
ported to affect cardiovascular fluctuations, such as hypnotics,
autonomic blockers, known substance abuse, psychoactive drugs
or neuroleptic medications, and a history of smoking within the
past 3 months, were also excluded. A total of 96 men were en-
rolled in this study between April 2004 and December 2004. In-
formed written consent was obtained from all participants, and
the experiment protocol was approved by the Ethics Committee
of Tzu-Chi Buddhist General Hospital, Hualien, Taiwan. After
evaluation using the five-item version of the International Index
of Erectile Function (IIEF-5) questionnaire, subjects older than
69 years (7 subjects in healthy group and 7 subjects in ED
group) were excluded due to their lower sexual activity. The
test groups consisted of the remaining 38 healthy men, who
showed normal sexual activity, and the remaining 44 men with
ED, who had been clinically diagnosed with a history of erectile
disorders. The subjects ranged from 40 to 69 years of age (Table
1). The two groups were divided into three distinct age catego-
ries using 10-year intervals. As stated above, all the subjects
had completed the IIEF-5 questionnaire, which included erectile
function, orgasmic function, sexual desire, intercourse satisfac-
tion and overall satisfaction. The possible scores for each indi-
vidual ranged from 5 to 25. We used this score to classify
the subjects into four categories. The result was 12 subjects
with severe ED (5–7), 26 subjects with moderate ED (8–14), 6
subjects with mild ED (15–21) and 38 subjects with no ED
(22–25) (Rhoden et al., 2002) (Table 2). The men without ED
had a mean score of 23, while those with ED had a mean score
of 11. All 44 ED patients then participated in a two-month oral
treatment of trazodone (50–200 mg, each night) (Fink et al.,
2003). They were assessed using short-term HRV analysis both
before the treatment and at 8 weeks after starting the treat-
ment. Among the ED subjects who initially participated in this
study, only 35 patients were included in the final results due
to discontinuation of treatment. The reasons for discontinuing
treatment included psychological burden, intolerance to side ef-
fects, intolerance to the poor response and catching a cold.
After trazodone treatment, the patients were also reevaluated
using IIEF-5. The post-treatment scores were divided into three
categories in order to assess any improvement namely IIEF-5
scores after treatment of between 22–25, 12–21 or 5–11 were
graded as satisfactory, acceptable and unsatisfactory, respec-
tively. Among the 35 ED patients who remained at the end of
the study, eight gave unsatisfactory results (22.86%), six gave
acceptable results (17.14%) and 21 gave satisfactory results
2.2. Processing of the electrocardiogram signal
The procedure for HRV analysis was designed according to the
standard method (Task Force of the European Society of Cardiology
and the North American Society of Pacing and Electrophysiology,
1996), and had been reported previously (Kuo et al., 1999; Liu
et al., 2003). In brief, a lead I electrocardiogram (ECG) was taken
for 5 min in the daytime while each subject lay quietly and
breathed normally. ECG signal acquisition, storage and processing
were performed using a HRV analyzer (SS1C, Enjoy Research Inc.,
Taiwan). Signals were recorded using an 8-bit analog-to-digital
converter with a sampling rate of 512 Hz. The digitized ECG signals
were analyzed online, and were simultaneously stored on a hard
disk for offline verification. The computer algorithm then identified
each QRS complex and rejected each ventricular premature com-
plex or noise according to likelihood using a standard QRS tem-
plate. Normal and stationary R-R interval values (RR) were
resampled and interpolated at a rate of 7.11 Hz to produce conti-
nuity in the time domain. This interpolation produced 2048 data
points over 288 s, which was used for the subsequent Fourier
Description data of study groups.
44 ± 1 16 24.8 ± 0.5 126.1 ± 1.6 76.6 ± 1.7
54 ± 1 13 24.4 ± 0.5 128.5 ± 2.7 77.6 ± 1.8
65 ± 19 24.8 ± 0.7 130.9 ± 2.9 75.9 ± 2.5
45 ± 1 17 24.7 ± 0.5 127.7 ± 1.7 77.5 ± 1.5
54 ± 1 18 24.7 ± 0.5 130.3 ± 2.1 81.8 ± 1.3a
65 ± 19 25.5 ± 0.8 129.6 ± 2.9 81.6 ± 1.2
Values are means ± SEM. BMI, body mass index; SBP, systolic blood pressure; DBP,
diastolic blood pressure.
ap < 0.05 vs. 40–49 years age category within the same population.
Description data of study groups.
GroupSub-groupIIEF-5 scoreAge (year)
BMI (m2/kg)SBP (mmHg)DBP (mmHg)
Patients with non-organic erectile dysfunction (ED)
53 ± 1
51 ± 4
52 ± 2
55 ± 3
24.6 ± 0.3
26.1 ± 1.0
24.5 ± 0.4
25.1 ± 0.6
128.0 ± 1.3
135.0 ± 2.7
128.4 ± 1.8
127.9 ± 1.5
76.8 ± 1.1
81.8 ± 1.4
80.2 ± 1.3*
79.1 ± 1.2
Values are means ± SEM. BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; Control, healthy group; Mild, mild grade of ED; Moderate,
moderate grade of ED; Severe, severe grade of ED.
*p < 0.05 vs. healthy group.
C.J. Chen et al./Clinical Neurophysiology 120 (2009) 348–352
2.3. Power spectral analysis of HRV
Power spectral analysis was performed using fast Fourier trans-
formation (FFT). The baseline shift was deleted, and a Hamming
window was used to attenuate the leakage effect (Kuo and Chan,
1993). For each time segment (288 s, 2048 data points), our algo-
rithm estimated the power spectrum density based on the FFT.
The resulting power spectrum was corrected for attenuation
resulting from the Hamming window (Stearns and David, 1988).
The power spectrum was subsequently quantified into the stan-
dard frequency-domain measurements as defined previously
(Kuo et al., 1999; Liu et al., 2003; Task Force of the European Soci-
ety of Cardiology and the North American Society of Pacing and
Electrophysiology, 1996), including variance (variance of RR-inter-
val values), very low-frequency power (VLF, 0.003–0.04 Hz), LF
(0.04–0.15 Hz), HF (0.15–0.40 Hz), LF/HF, normalized HF (HF%)
and LF (LF%). LF% was calculated from LF/(total power-VLF) ? 100,
and HF% from HF/(total power-VLF) ? 100. Variance, VLF, LF, HF,
and LF/HF were logarithmically transformed to correct for skewed
distributions (Kuo et al., 1999). It should be mentioned that these
parameters are clearly interdependent.
2.4. Statistical methods
The differential effects in terms of HRV parameters between the
patients and the healthy men within the three age categories and
within the three severity groups were compared using two-way
or one-way analysis of variance (ANOVA). Post hoc comparisons
using Fisher’s least significant difference test were applied for a
posteriori comparison of the means as appropriate. Comparisons
between the pre- and post-treatment data for the same group were
performed using the paired Student’s t-test. Comparisons between
responses were performed using the Student’s t-test. Statistical
significance was assumed for p < 0.05. Values are expressed as
means ± SEM.
There were no statistically significant differences in age, body
mass index, systolic blood pressure and diastolic blood pressure
among these age-matched groups (Table 1). However, the patients
with non-organic ED revealed a significantly lower variance, HF
and HF%, and a significantly higher LF/HF and LF% compared with
the healthy group over all age categories. No significant difference
was detected for VLF and LF except for the 40- to 49-year subgroup
3.2. ED subgroups
Except for the moderate ED group, which revealed a higher dia-
stolic blood pressure than the control group, there were no statis-
tically significant differences in age, body mass index, systolic
blood pressure and diastolic blood pressure among the different
severity groups and the healthy control group (Table 2). As com-
pared with the healthy control group, all the HRV parameters for
the patient groups were significantly different. In addition, the val-
ues for variance and HF showed severity-dependent decreased
changes. However, the values for RR, LF/HF, LF% and HF% did not
show a severity-dependent pattern (Fig. 2). As compared with
the pre-treatment values, patients treated with trazodone experi-
encing satisfactory response showed a significant restoration of
all HRV parameters. However, patients with unsatisfactory re-
sponse, even though treated with identical medication, signifi-
cantly showed lowered RR and HF values, but the other HRV
parameters did not change significantly when the pre-treatment
Fig. 1. Mean R-R intervals (RR) and all measures of heart rate variability among patients with non-organic erectile dysfunction (ED) and among healthy groups of men across
10-years age category between 40 years and 69 years. Variance, variance of RR-interval values; VLF, very low-frequency power; LF, low-frequency power; HF, high-frequency
power; LF/HF, ratio of LF to HF; LF%, normalized LF; HF%, normalized HF. Values are means ± SEM; nu, normalized units.*p < 0.05 vs. the group of age-matched healthy men,
and?p < 0.05 vs. 40–49 years age category from the same population.
C.J. Chen et al./Clinical Neurophysiology 120 (2009) 348–352
and post-treatment data for patients with an unsatisfactory
response were compared (Fig. 3).
Our present study used spectral analysis of HRV to explore the
sympathovagal dysfunction among patients with non-organic ED.
We found that patients with non-organic ED, compared with the
age-matched healthy group, had higher LF% and lower HF. Since
LF% and HF are indices of cardiac sympathetic and vagal regula-
tions, respectively. Our results indicate that non-organic ED pa-
tients showed a significant cardiac sympathetic excitation linked
to cardiac vagal depression. The previous evidence (Giuliano and
Rampin, 2004; Lindsey et al., 2003; Marson et al., 1993) had shown
Fig. 2. Mean R-R intervals (RR) and all measures of heart rate variability in patients with non-organic erectile dysfunction (ED) across different severity groups and the
healthy group of men. Variance of RR-interval values; VLF, very low-frequency power; LF, low-frequency power; HF, high-frequency power; LF/HF, ratio of LF to HF; LF%,
normalized LF; HF%, normalized HF; Control, healthy group; Mild, mild grade of ED; Moderate, moderate grade of ED; Severe, severe grade of ED. Values are means ± SEM; nu,
normalized units.*p < 0.05 vs. healthy group and?p < 0.05 vs. mild group.
Fig. 3. Mean R-R intervals (RR) and all measures of heart rate variability in patients with satisfactory response and an unsatisfactory response before (pre) and after (post)
two months of trazodone treatment. Variance of RR-interval values; VLF, very low-frequency power; LF, low-frequency power; HF, high-frequency power; LF/HF, ratio of LF to
HF; LF%, normalized LF; HF%, normalized HF. Values are means ± SEM; nu, normalized units.*p < 0.05 vs. Pre at the same group, and?p < 0.05 vs. satisfactory response.
C.J. Chen et al./Clinical Neurophysiology 120 (2009) 348–352
that penile erection is controlled by the sympathetic pathways
(dorsolumbar spinal cord) and parasympathetic branches (sacral
spinal cord) of the autonomic nervous system, and therefore our
results indicate that the sympathovagal dysfunction that accompa-
nies non-organic ED may not be solely confined to the sexual or-
gan, but is likely to be systemic. The finding showing altered
cardiovascular autonomic functions is supported by a recent paper
(Stuckey et al., 2007), and should serve to remind clinicians when
treating their patients to consider carefully their approach to non-
organic ED. For example, an autonomic function examination such
as HRV analysis can be done to provide a rapid screening of sys-
temic autonomic disturbance. Then, the treatment to restore the
autonomic function can be considered. Whether patients with
non-organic ED are simply ED patients with an undiagnosed organ-
ic disease is an interesting proposition, and warrants further
Without significant changes in the systolic and diastolic blood
pressures, patients with non-organic ED exhibited distinctly differ-
ent evaluations of their cardiac sympathetic modulation across all
age categories compared with the age-matched healthy group of
men. The changes in the spectral components of the HRV appear
to be more sensitive to reflect non-organic ED than that in the rest-
ing arterial pressure. Although direct detection of penile sympa-
thetic activity was not available for this study, our results support
that sympathetic pathways play an anti-erectile role. Our results
further reveal that sympathetic over-activity also seems to occur
in the cardiovascular systems of patients with non-organic ED.
Furthermore, the present study also revealed that patients with
non-organic ED have significantly lower variance and HF compared
with the age-matched group of healthy men. RR and variance are
sidered to specifically represent vagal control of the heart rate. RR
and variance, influenced by both the sympathetic and the parasym-
sent vagal control of heart rate for the most part (Task Force of the
European Society of Cardiology and the North American Society of
Pacing and Electrophysiology, 1996). Our results support the previ-
ous evidence (Giuliano and Rampin, 2004) that had suggested that
parasympathetic pathways play a pro-erectile role. Our results also
diovascularsystem. The evidence reveals that there was a sustained
depression of cardiac vagal activity, which indicates that a patient
may have an increased risk of cardiovascular diseases (Huikuri
et al., 1996). For bothcliniciansandpatients,paying attentionto va-
gal failure is a worthwhile effort.
Much evidence has suggested that both sympathetic and para-
sympathetic innervations to the penis are essential for a normal
erectile function (Giuliano and Rampin, 2004; Lindsey et al.,
2003; Marson et al., 1993). Our results showing that patients with
non-organic ED had a combined cardiac autonomic imbalance sug-
gest that autonomic dysfunction is not likely to be just a local prob-
lem but may be central in origin. The brain stem autonomic nuclei
(Allard and Giuliano, 2001; Giuliano and Rampin, 2004) and the
hypothalamic paraventricular nucleus (Marson et al., 1993; Giuli-
ano and Rampin, 2004) may be possible candidate areas. The pos-
sibilities of a peripheral neuropathy affecting non-myelinated
fibers or a degenerative disease of the autonomic nervous system,
however, are not ruled out in this study. Further investigation is
still needed to clarify this issue.
Using similar techniques, we found that the changes in auto-
nomic modulation, especially cardiac vagal function, coincide with
the different severities of non-organic ED. We further found that all
the autonomic changes were reversed after satisfactory treatment
among patients with non-organic ED, but that this did not happen
among patients who had received an unsatisfactory treatment. The
changes in HRV measurement would seem to provide new insights
into the probable influence of autonomic regulation on erectile
function and into the activity of drugs that are capable of improv-
ing erectile performance. Therefore, short-term HRV spectral anal-
ysis is not only a good way to assess the nature of a complex
disease such as ED, but could also be a convenient approach to
the development by urological clinicians of individualized therapy
for each patient.
This study was supported by a Grant (YM-97A-C-P506) from
the Ministry of Education, Aim for the Top University Plan, and
by a Grant NSC-95-2314-B-010-088 from National Science Council,
Taiwan. We thank Ms. Aggie W.-F. Lu, Ms. Ryo Arai and Ms. Ying-
Hua Huang for their excellent technical support.
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