Martin Plachy

24 hour ambulatory blood pressure values corresponding to office blood pressure value of 130/80 mm Hg

BACKGROUND 24 hour ambulatory blood pressure monitoring (ABPM) values for patients who have office BP of 130/80 mm Hg have not been clearly reported. AIM The determination of ABPM values in treated hypertensive subjects corresponding to a mean office BP of 130/80 mm Hg. METHODS BP measurement in subjects 40-70 years old, by ABPM and mercury sphygmomanometer. The inclusion criteria were: mean office BP systolic (SBP) 128-132 mm Hg and diastolic (DBP) 78-82 mm Hg. Seventy six subjects met all study inclusion criteria. RESULTS Mean office BP: SBP 129.5 ± 1.1 mm Hg, DBP 79.9 ± 1.3 mm Hg. Mean 24 hour BP: SBP 121.9 ± 2.0 mm Hg, DBP 73.1 ± 1.9 mm Hg. Mean awake BP: SBP 124.9 ± 2.4 mm Hg, DBP 75.5 ± 2.2 mm Hg. Mean asleep BP: SBP 109.1 ± 3.9 mm Hg, DBP 63.3 ± 4.0 mm Hg. CONCLUSIONS The target values of ABPM identified in this study can be used in clinical practice and will contribute to risk stratification and treatment of hypertension.

Excitation specificity of repolarization parameters

The excitation specificity of QT dynamic parameters was tested on three groups of subjects: healthy subjects; non-medicated hypertensive subjects with metabolic syndrome; and subjects with essential hypertension. Four different excitations of RR were used: bicycling exercise; tilt with breathing 0.1 and 0.33 Hz; and deep breathing. Linear dynamic feedback model of QT/RR coupling was supposed at the analysis and next repolarization parameters were tested: QTc; gain of QT/RR coupling for slow and fast RR variability; time constant of QT adaptation; and random QT variability. Results: Dynamic repolarization parameters statistically significantly depend on the type of RR excitation. The gain of QT/RR coupling for slow RR variability, the time constant of QT adaptation and QTc are maximal at RR excitation given by the bicycling exercise. The frequency of breathing, i.e. corresponding vagal modulation has no effect on repolarization parameters. The measurements with deep breathing, without any other slow excitation of heart rate, has low signal-to-noise ratio of analyzed data and resulting QT parameters are inaccurate. Conclusion: The use of heart rate excitation and all measurements conditions should be defined for the exact analysis of the repolarization dynamic parameters.

Noninvasive detection of vessel stiffness from continuous blood pressure recordings in hypertensive subjects

This paper presents results of blood pressure dynamicity analysis aimed at vessel stiffness detection and subsequent cardiac risk stratification. We analyzed ECG and BP parameters from 12 normotensive young healthy volunteers, 10 old healthy volunteers, and two groups of hypertensive patients-12 young non-medicated hypertensive subjects with no other known complications and 16 hypertensive non-medicated subjects with confirmed obesity (according to waist circumference), hyperlipidemia or diabetes mellitus. The dynamic parameters obtained from a derivative continuous blood pressure signal provide additional information about vessel compliance. They can differentiate hypertensive subjects according to the level of cardiovascular risk

EARLY AUTONOMIC CHANGES IN PATIENTS WITH NEWLY DIAGNOSED ARTERIAL HYPERTENSION: PP.25.05

Objective: The autonomic nervous system plays a key role in the regulation of blood circulation and its abnormal function is a major factor involved in the early phases of essential arterial hypertension. The objective of the study was to assess the differences between short-term variation in heart rate and blood pressure in healthy individuals and in a group of patients with newly diagnosed mild essential arterial hypertension. Design and Method: Three continuous 5-minute measurements of the ECG and blood pressure in supine position with different breathing patterns (spontaneous breathing, paced breathing 0.1 Hz and 0.33 Hz), were applied at 2 groups of subjects: young healthy (YH, 31 subjects, 13 female) and patients with newly diagnosed mild arterial hypertension (HT, 29 subjects, 12 female). Analyzed parameters: heart rate (HR), heart rate variability spectral power in low frequency (HRVlf) and high frequency (HRVhf) power bands, systolic pressure (SBP), diastolic pressure (DBP) and baroreflex sensitivity (BRS). Results: Mean HR [beat/min] over groups YH/HT at 0.1Hz breathing is 69.9/73.2 (p = NS), during spontaneous breathing 66.1/72.9 (p = NS), and 0.33Hz breathing 67.1/72.8 (p = NS); mean HRVlf [ms2/1000] at 0.1Hz is 17.9/8.5 (p < 0.01), during spontaneous breathing 3.8/2.0 (p = NS) and at 0.33Hz 2.2/0.8 (p < 0.05); mean HRVhf [ms2/1000] at 0.1 Hz is 2.4/1.3 (p = NS), during spontaneous breathing 2.6/1.3 (p = NS) and at 0.33 Hz 2.1/0.7 (p = NS); mean BRS [ms/mmHg] at 0.1 Hz is 17.3/11.2 (p < 0.01), during spontaneous breathing 10.6/8.3 (p = NS) and at 0.33 Hz 9.9/5.9 (p < 0.05). Conclusions: Increased risk of cardiac mortality is closely connected to decreased HRV and BRS as the markers of the short-term circulation control dysfunction. There are no significant differences between both groups in HRVlf, HRVhf and BRS during spontaneous breathing. Group differences in HRVlf and BRS are more significant (p < 0.01) at 0.1Hz breathing than during 0.33Hz breathing (p < 0.05). The 0.1Hz paced breathing is simple and convenient approach to amplify inter-groups differences of the cardiovascular control detected by the HRVlf and BRS in early stages of hypertension.

Blood Pressure Dynamics in Hypertensive Subjects During Tilt Table Test

Blood pressure dynamicity during tilt table measurement is discussed. We analyzed ECG and BP parameters from 14 normotensive young healthy volunteers, 15 old healthy volunteers, and two groups of hypertensive patients - 20 non-medicated hypertensive subjects with no other known complications and 21 hypertensive non-medicated subjects with confirmed obesity (according to waist circumference), hyperlipidemia or diabetes mellitus. The dynamic parameters, such as pulse pressure, maximum of derivative BP, difference between maximum and minimum of derivative BP and SBP peak - DBP depression time were obtained from derivative continuous blood pressure signal recordings. We have found that the age factor plays a more significant role in dynamic parameters change and in inter-group differentiation than additional risk factors of hypertensive subjects.