ABSTRACT
Objective: the aim of this work is to study HRV parameters in patients with unstable angina
Materials and Methods: the study comprised 50 patients with unstable angina; 35 males and 15 females with mean age 45 +/- 94 yrs. beside ten healthy control subjects. All patients and control subjects were subjected to thorough history taking, full clinical examination, electrocardiography, routine laboratory investigations, assessment of heart rate variability [HRV] using time domain [NN 50 and RMSSD] for non-spectral analysis and frequency domain [LF, HF and LF / HF ratio] for spectral analysis, echocardiographic examination and coronary angiography
Results: there was significant global reduction in HRV parameters in patients with unstable angina compared to control group as mean NN 50 was 3.2 ms in patients compared to 20.1 ms in control group [P < 0.01]. Mean RMSSD was 10.1 ms in patients us 42.1 ms in control group [P < 0.01], HF was 50 ms2 in patients us 350 ms2 in control group and HF was 32.5 ms2 in patients compared to 246 ms2 in control group. However, there was no significant difference between the patients and controls as regards LF/HF ratio [P > 0.05]. Mean W H F ratio was significantly higher. Among patients who experienced recurrent chest pain during hospitalization as the mean LF/HF ratio among five patients who developed recurrent chest pain was 1.9 vs 1.5 in other patients [P < 0.05]. There was significant correlation between HRV and both EF [r = 0.8, P < 0.05] and severity of coronary artery disease [r = 0.7, P < 0.05]. There was no significant correlation between HRV and age [r = 0.2, P > 0.05, end systolic diameter [r = 0.3, P > 0.05] and end diastolic diameter [r = 0.02, P > 0.05] of the left ventricle
Conclusion: all parameters of HRV except LF/H.F ratio were significantly lower among patients with unstable angina compared to control group. HF/HF ratio in particular was significantly lower among patients who experienced recurrent chest pain during hospitalization. Finally there was positive correlation between HRV parameters .and both EF and severity of coronary heart disease
Comment: HRV can be a useful parameter for risk stratification of patients with unstable angina
ABSTRACT
This study included 60 patients with essential hypertension [32 females and 28 males], their age ranged from 43 to 59 years [mean 52 +/- 4 Twenty normal, age and sex matched, healthy subjects were also studied as a control group. All subjects were subjected to 24 hours Ambulatory Blood Pressure Monitoring [ABPM], EGG and Echocardiography. According to echocardiographic parameters, hypertensive patients were classified into two groups. hypertensives with left ventricular hypertrophy [LVH] and hypertensives without LVH. This study revealed: Significant increase in left ventricular mass and LVH in hypertensive versus normotensive group. LVH is more closely related to ambulatory blood pressure than to casual blood pressure. Closer relation of systolic over diastolic BP to the degree of hypertrophy, another evidence that wall stress which is mostly related to systolic blood pressure [SBP] is a key factor influencing LVH development. Significant increase in left ventricular mass and LVH in hypertensives with marked fluctuation in BP throughout 24 hours versus hypertensives without marked fluctuations. Significant increase in LVM in hypertensive non-dippers versus hypertensive dippers. The propensity for LVH among patients with hypertension is increased with age and with the duration of hypertension. The results of this study shows a significant relationship between cir-cadian blood pressure changes and left ventricular hypertrophy which underlines the importance of ambulatory blood pressure monitoring in evaluating the effects of hypertension in relation to left ventricular hypertrophy