الفهرس 
Patients and methodsOnly 14 pages are availabe for public view
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Abstract
Analysis of heart rate variability (HRV) is a noninvasive method
of assessing the integrity of neural input to the cardiovascular. system
(Pagani et al., 1986). Bigger and Coworkers in 1992 have extended the
use of HRV analysis into the clinical domain by demonstrating its value
in risk stratification of patients after myocardial infarction. This finding
has been confirmed by other investigators (Cripps et a1.,1991) and has
also been found in patients with stable coronary artery disease (Rich et al
.,1988).
The aim of this work is to study H.R.V. parameters in patients with
unstable angina and to see if these parameter have any prognostic value.
Fifty patients with unstable angina were included in this study.
They were selected from CCU at Benha University Hospitalduring the .
period from May 2001 to May 2002.Ten healthy control subjects were
also included for comparison.
All patients are subjected to the following:
1- Thorough history taking and. clinical examination to detect risk
factors of coronary artery disease and to exclude other causes of
chest pain.
2- Resting E.C.G: resting 12 lead. E.C.G. was done to confirm the
diagnosis of unstable angina and exclude ST elevation MI, AF and
conduction defects.
3- Routine laboratory investigations:
Blood sugar, serum creatinine and cardiac enzymes were done to
all patients to exclude M.L, renal failure and diabetes mellitus. ~’1!·_------<0~------_..s~
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4 - H. R.V analysis:
H.R.V. was studied using Schiller analysis program by Schiller
AG CS100 device which determine H.R.V. by recording 1024 hart beats,
digitize the data and calculate parameters of H.R.V. which include
spectral and non spectral measurements.
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The following parameters were recorded for each patients :
Time domain (NN50and rMSSD) for non spectral analysis ofH.R.V.
Frequency domain (L.F,H.F and L.FIH.F ratio) were
recorded for spectral component ofHRV.
5- Echocardiographic examination, full echocardiographic
examination was done to all patients mainly to study the systolic
and diastolic function of the heart through evaluation of ejection.
fraction, wall motion abnormalities and exclude congenital; and
rheumatic heart disease.
6- Coronary angiographic study: was done to all patient to detect the
underlings coronary artery disease and assessment ofits severity.
Diabetic patients, patients with congenital, rheumatic heart
disease, heart failure, renal failure, atrial fibrillation and conduction
defects were excluded from this study.
Statistical analysis of the result of this study revealed:
1- There is significant global reduction in HRV parameters in patients
with unstable angina compared to control group.
_ NN50 was 3.2 ms in patient compared to 20.1 ms in control study
(P < 0.01).
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Summary
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_ rMSSD was 10.1 ms in patient compared to 42.1 ms in control
study (P < 0.01).
_ L.F. was 50 ms2• in patients compared to 350ms2 in control group
(p < 0.001).
_ H.F. was 32.5 ms2 in patients compared to 246 ms2 in control
group
However, there’s no significant difference between the patient and
control groups as regard to L.F./H.F. ratio (P > 0.05).
2- L.F./H.F. ratio has a prognostic value in patients with unstable angina
as shown in this study that revealed increased L.F./H.F. ratio in five
patients (10%) how developed recurrent chest pain during follow-up
period. L.F./H.F. ratio was 1.9 in patients with recurrent chest been
compared to 1.5 in patient without (P < 0.05).
In the present work correlation studies revealed significant
correlation between heart rate variability and left ventricular ejection
fraction’ (r = 0.8, p< 0.05). Also it was found that there is a significant
correlation between HRV and the severity of coronary artery disease
(percentage of luminal diameter stenosis) (r = 0.7, P < 0.05).
However, there is no significant correlation between HRV and !lge
(r = 0.2, P > 0.05), end systolic diameter (r=- 0.03,p> 0.05)and end.
diastolic diameter (r =- 0.02, P > 0.05). So HRV studies in patients with
unstable angina can detect high risk group to whom aggressive therapy
should be given.