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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 26, No 6, November/December 2015
220
AFRICA
study that has assessed the mechanical and electromechanical
functions of the LA in patients with PCOS.
Previous investigations suggested that endothelial and
diastolic dysfunction occurs in patients with PCOS due to insulin
resistance and high androgen levels.
14,15
Diastolic dysfunction
is considered to be an early sign of coronary artery disease.
Accordingly, Yarali
et al
. reported that PCOS patients had a
lower peak E velocity and E/A ratio.
16
A study showed a negative correlation between insulin levels
and E/A ratio, which suggests that PCOS patients may be more
prone to develop diastolic dysfunction.
17
Another study showed
that LV ejection fraction, transmitral E and A waves, E/A ratio,
deceleration time, isovolumetric relaxation time and tissue
Doppler parameters were not significantly different between
patients with PCOS and control subjects.
18
In our study, LV
systolic function and transmitral E and A waves were similar in
the two groups, but E/A ratio was decreased in the study patients,
suggesting impaired diastolic function.
Atrial fibrillation is the most commonly observed arrhythmia
in clinical practice and is associated with cardiovascular
morbidity and mortality.
19-21
Identifying the risk factors that
generate AF is important. It was thought that enlargement
and increased pressure of the LA have an effect on P-wave
disturbances.
22-24
The presence of P-wave dispersion, and inter-
and intra-atrial conduction delays mean that sinus impulses
have inhomogeneous propagation. This is a well-known
electrocardiographic characteristic of atria that are prone to
AF.
6,25
The autonomic nervous system plays an important role in
heart rate and the conduction system. Imbalance between the
sympathetic nervous system and vagal tone is an important
predictor of AF.
26,27
Gonadal sex hormones affect heart rate and atrioventricular
conduction time. Fulop
et al.
reported that heart rate is
moderately reduced after surgical castration in both male
and female canines. Heart rate is increased and PQ interval is
lengthened with oestrogen replacement in male canines, and with
testosterone replacement in female canines. Therefore, oestrogen
and testosterone have identical effects on the heart rate and
atrioventricular conduction time.
3
In our study, Pd, inter- and intra-atrial conduction times were
increased in patients with PCOS. Therefore resting heart rate was
higher in these patients. Elevated serum levels of oestrogen and
testosterone may explain these findings.
Ventricular filling pressure is an indicator of LV diastolic
function, and LA function is an important determinant of
LV diastolic filling.
28
LA passive emptying volume is related
to increased LV end-diastolic pressure.
12
We found that LA
mechanical function was impaired in PCOS patients.
Insulin resistance, obesity and hyperlipidaemia, risk factors
for cardiovascular disease, are more frequent in patients with
PCOS.
2
Studies showed that arterial stiffness, endothelial
dysfunction and LV diastolic dysfunction were increased in
obese patients with PCOS.
29,30
Additionally, diastolic function
may worsen with age. In our study E/A ratio was lower in women
with PCOS, even though the PCOS patients were significantly
younger. BMI differences were insignificant between the groups.
Impairment of LA mechanical and electromechanical
function is known to be a risk factor for AF. LA mechanical
function, conduction times and Pd have not been evaluated
previously in patients with PCOS. Although there were no
known cardiac risk factors, obesity or insulin resistance, we
found not only impaired LV diastolic parameters but also
increased LA conduction times and Pd in these patients. Hence,
we suggest that decreased LA mechanical function, lengthening
inter- and intra-atrial conduction times, and increased Pd may
occur before the appearance of cardiovascular risk factors such
as hypertension, diabetes mellitus and hyperlipidaemia.
Age is an important risk factor for the development of AF.
19
However Turhan
et al
. reported a positive correlation between
age and Pd, and LV diastolic parameters.
31
In our study, although
the patients with PCOS were younger, they still had significant
impairment in Pd, LA mechanical dysfunction, and increased
electromechanical delay.
Our study has some limitations that need to be addressed. It
was based on a relatively small group of patients and the patients
with PCOS were younger than the controls. There is a need for
longitudinal studies to follow up on subjects and controls.
Conclusion
This study showed that patients with PCOS had increased
inter- and intra-atrial conduction delays, decreased LA passive
emptying volume and fraction, and lower E/A ratios. Increased
Pd is a risk factor for developing AF, therefore PCOS patients
may have a high risk for developing atrial arrhythmias, unless
they have other traditional cardiovascular risk factors.
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