J R Soc Med 2002;95:445-447
doi:10.1258/jrsm.95.9.445
© 2002 Royal Society of Medicine
Cardiovascular autonomic dysfunction in Africans infected with human immunodeficiency virus
Divine Nzuobontane MD MPH
Blackett Kathleen Ngu MD FRCP 1
Kuaban Christopher MD 1
Wirral Hospital NHS Trust, St Catherine's Hospital, Birkenhead CH42 0LQ,
UK
1 University Hospital Centre and Faculty of Medicine and Biomedical Sciences,
Yaounde, Cameroon
Correspondence to: Dr Divine Nzuobontane E-mail:
divine.nzuobontane{at}exchange.nwest.wirral-ha.nhs.uk
 |
SUMMARY
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The effects of human immunodeficiency virus (HIV) on cardiovascular
autonomic
function have been little investigated in African patients.
We
performed standard heart-rate and blood pressure tests on
75 consecutive
consenting patients referred for an HIV test
in Yaounde, Cameroon. 54 patients
proved to be HIV-infected
(30 having progressed to AIDS).
Cardiovascular autonomic dysfunction was present in 8 (28%) patients with
AIDS and in 1 (4%) HIV-positive patient without AIDS; no HIV-negative
individuals had abnormal results. If borderline results are included, over 80%
of HIV-positive patients had cardiovascular autonomic dysfunction.
In HIV-infected patients, simple tests such as blood pressure responses to
standing or handgrip can warn of cardiovascular autonomic dysfunction, thus
signalling the need for added precautions when invasive procedures are
proposed.
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INTRODUCTION
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28.1 million people are living with HIV infection in Africa
today; another
9300 are infected with the virus every day and
2.3 million die from it each
year
1. In Cameroon,
the prevalence
of the infection in the general population rose from 4% in 1996
to
11% in
2001
2,3.
Although HIV infection is well known to affect
the heart, its effects on
cardiovascular autonomic function
have been little studied in African
patients. The issue is important
because of the high prevalence of infection
and the implications
for medical care. In one of the earliest African studies,
Rogstadt
et
al.4 examined
autonomic function in patients at various stages
of HIV infection and in
normal controls. They found evidence
of substantial impairment in
cardiovascular autonomic function
in AIDS patients, with worsening of
autonomic function as HIV
disease progressed. We investigated the presence of
cardiovascular
autonomic dysfunction in Cameroonian patients at various stages
of
HIV infection.
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METHODS
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We recruited 75 consecutive consenting patients referred for
HIV tests
(ELISA and western blot) at the University Hospital
Centre Yaounde, Cameroon,
because of clinical suspicion of HIV
infection. Patients with a documented
history of cardiovascular
disease before the HIV test were excluded. We also
excluded
very ill patients who could not satisfactorily perform the autonomic
test
manoeuvres. 54 (72%) of the patients were HIV infected, of whom
30 had
AIDS according to the WHO/Bangui clinical definition
for AIDS in
Africa
5.
All patients were clinically assessed for symptoms and signs of heart
disease as well as to allow classification of HIV-infected patients into
groups with and without AIDS. Cardiovascular autonomic function was tested
before the patients' HIV status was known, by a physician who was not aware of
the cardiovascular-related clinical findings. Cardiovascular autonomic
function was assessed by five
standard6 blood
pressure and heart-rate tests. Blood pressure tests were conducted with an
automatic electronic blood pressure machine while heart-rate variations were
determined by manually measuring R-R intervals of traces obtained with a
semi-automatic electrocardiograph (ECG). Each test was performed only after
blood pressure and heart-rate had returned to baseline.
Blood pressure response to standing was measured as the difference
in systolic blood pressure with the patient supine and immediately after
assumption of the erect posture.
Blood pressure response to sustained handgrip was the difference
in diastolic blood pressure before and after maintenance of sustained handgrip
with maximum force.
For heart-rate response to standing from lying position we
calculated the ratio of the longest R-R interval to the shortest R-R interval
after the patient moved quickly from supine to upright posture.
For heart-rate response to Valsalva manoeuvre the patient was
asked to blow through a mouthpiece connected to a modified sphygmomanometer
and hold the pressure at 40 mmHg for 15 s. The ECG was recorded during and
after the manoeuvre. The result was recorded as the ratio of the longest R-R
interval during the manoeuvre to the shortest R-R interval after the
manoeuvre.
For heart-rate variation during deep breathing the patient was
asked to breathe deeply at six breaths per minute, an ECG being recorded
throughout the procedure. The mean of the difference between minimum and
maximum heart-rates obtained from R-R intervals was determined for six
breathing cycles.
For grading of cardiovascular autonomic function, results were classified
into normal, borderline, and abnormal (scored 0, 1 and 2 respectively) as
shown in Table 1. An overall
score 
3 was considered to indicate normal autonomic function. Scores >
3 and < 8 were considered borderline and scores 
8 were judged
abnormal.
Comparisons were done by chi-square analysis with Yates' continuity
correction when necessary. Analysis of variance (anova) was performed for
comparison of means of more than two groups and Student's t-test for
comparison of two different groups. P < 0.05 was taken as
statistically significant.
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RESULTS
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Clinical features
Mean age of HIV-infected patients was 34 years and of HIV-negative
patients
30 years. Body mass index was 20.55 and 21.85, respectively.
None of either
group gave a history of diabetes mellitus but
we did not undertake any blood
glucose tests. None was on antiretroviral
medications, since they were
recruited before their HIV status
was known. Since we excluded individuals
with a history of cardiovascular
disease including hypertension, no patient
was on antihypertensive
medications. The possibility of alcoholism was
difficult to
investigate. Most of the patients had presented with
non-cardiovascular
symptoms, cough and chest pain being the most prevalent. 23
patients
had coexisting pulmonary disease (7 AIDS, 10 HIV-positive non-AIDS,
and
6 HIV-negative), ranging from pneumonia to non-specific chest
infection.
We checked all medical records to exclude pulmonary
tuberculosis but we cannot
firmly exclude this diagnosis in
some patients since we did not undertake any
chest X-rays or
sputum cultures or conduct clinical follow-up.
Cardiovascular autonomic function
Mean diastolic response to persistent handgrip and systolic response to
standing were significantly higher in the AIDS group than in the HIV-negative
group; likewise, the mean heart-rate response to Valsalva manoeuvre was higher
in the AIDS group (Table 2).
For most autonomic function tests mean values deviated from normal as disease
progressed to AIDS.
Cardiovascular autonomic function was abnormal in 8 (28%) AIDS patients but
in only 1 HIV-positive patient without AIDS
(Table 3). None of the
HIV-negative patients had abnormal function.
Only 1 of the 30 AIDS patients had completely normal cardiovascular
autonomic function. More than 80% of HIV-infected patients had either abnormal
or borderline results—twice the prevalence in seronegative patients.
|
DISCUSSION
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Our results illustrate that cardiovascular autonomic dysfunction
is common
in African HIV-infected patients and that autonomic
function deteriorates with
progression to AIDS. Similar findings
have been reported by others in previous
studies
4,7,8,9.
The findings resemble those reported by Rogstadt et
al.4 in their
Kenyan study; however, in contrast to their case—control design, we
adopted a cross-sectional design because of the difficulty in getting
appropriate HIV-seronegative controls in our setting. They used two additional
tests—the cold face test and response to mental stress—and their
criteria for diagnosis of autonomic dysfunction were slightly different from
ours. Like them, we found a significant difference between groups for the
Valsalva test. Unlike them, we did not show significant differences for other
heart-rate tests, but we did find clear differences for blood pressure tests.
Probably the divergence of results is related to differences in design, sample
size, patient selection and grading of autonomic function tests.
Autonomic dysfunction in HIV infection could have far-reaching consequences
in the African setting. Because HIV affects various organ systems, invasive
procedures are often needed for diagnostic and therapeutic purposes. In the
late stages of HIV infection, screening for autonomic dysfunction may be
advisable before invasive procedures such as pericardiocentesis, because of
the risk of cardiovascular collapse or sudden death. Syncopal reactions have
been reported10 in
HIV patients with abnormal autonomic function during such procedures.
Blood pressure tests may be a good option in African clinical practice,
where heart-rate tests are often difficult to perform. In addition, our
results indicate that, apart from the Valsalva manoeuvre, heart-rate tests may
have only a limited role in discriminating autonomic function in HIV-infected
patients. This needs to be explored further.
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REFERENCES
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|---|
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AIDS Control Execution Manual. Yaounde: MPH,2001
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Cardiovascular autonomic neuropathy in HIV infected patients. Sex
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SUMMARY
INTRODUCTION
