WHAT OPTIONS DOES THE SUPINE-STANDING-SUPINE TEST OFFER TO PATIENTS WITH HYPERTENSION? DEMONSTRATIONS OF EXAMPLES.

AIMS
The purpose of the study was to demonstrate autonomic nervous system (ANS) changes associated with treatment in hypertensive patients and utilization of these measurements in practice.


METHODS
Hypertensive patients were examined before the start of treatment and after blood pressure compensation. The telemetric system VarCor PF 5 was used for non-invasive heart rate registration and automatic evaluation of heart rate variability (HRV) parameters. The supine-standing-supine test with ortho-clinostatic loading in standard conditions was used for HRV evaluation.


RESULTS
The influence of antihypertensive therapy on ANS was demonstrated in two cases. The first was a case of a responder to therapy and the second case was example of a non-responder to monotherapy regarding more therapeutic steps for blood pressure control. Different modes of results presentation are demonstrated: 3D graph, numeric form of standard parameters of HRV, computer interpretation of results by means of complex parameters and indices in numeric, graphic and verbal form with functional age calculation, cross graph of vagal activity index versus sympatho-vagal balance index was used for repeated measurements and follow-up. The increased spectral performance with augmented vagal activity and slope down of sympatho-vagal ratio are evident after blood pressure control achievement. Improvement of functional age parameter associated with blood pressure compensation is visible using a complex age-dependent parameters interpretation.


CONCLUSIONS
HRV evaluation in hypertensive patients provides new parameters for patient's examination. These parameters are influenced by both the illness itself and by pharmacotherapy. Such an approach offers more complex information about patient.


INTRODUCTION
Blood pressure (BP) is the result of peripheral vascular resistance, central venous pressure and cardiac output interactions.It is self-evident that heart rate is an important parameter of actual circulatory compensation as cardiac output is dependent on heart beat frequency.Blood pressure regulation in hypertensive patients is still inadequate despite increasing knowledge of the aethiopathogenesis of this condition and the wide range of pharmacotherapeutic modalities available.Blood pressure is continuously under the control of multiple regulatory processes including the ANS as a major regulatory and integrative system 1 .Heart rate variability (HRV) measurement is a well-defi ned noninvasive method of evaluating the ANS (ref. 2 ).Spectral analysis (SA) of HRV enables us to distinguish three main spectral components from short-term recordings: a high frequency (HF) component (0.15-0.40 Hz), a low frequency (LF) component (0.05-0.15 Hz) and a very low frequency (VLF) component (≤ 0.04 Hz) (ref. 2,3 .The supine-standing-supine test is a mode of evaluating the short-term HRV records using standardised orthostatic loading for facilitation of sympatho-vagal balance.Detailed analysis of large number of HRV parameters can be simplifi ed using age-standardised parameters in the spectral analysis of HRV and by the method of complex indices assessment 4 .

METHODS AND CLINICAL APPLICATION
The activity of the ANS is dynamic variable representing the reaction of ANS to currently operating external and internal stimuli in interaction with responses to stimuli acted in past 5 .Therefore the supine-standing-supine test was used for HRV evaluation.This test consists in assessment of autonomic reactions based on short-term record of heart rate in defi ned conditions.7][8] ).Record of RR intervals and HRV analysis were provided by using of VarCor PF5 microcomputer system for telemetric assessment of short term heart rate variability in time and frequency domain with application of fast Fourier transformation and partially modifi ed algorithm CGSA (coarse-graining spectral analysis) 9 .Measured parameters with similar course and age dependency were processed by method of complex indicators with calculation so called functional age by method of Stejskal and Šlachta 5,10,11 .Four types of results were assessed: 1) Three dimensional (3D) graph of HRV.Thus the only variable was new medicament therapy.All patients were in sinus rhythm.All patients were examined in the morning time fasting, with omission of tabaco, coffee and alcohol.The fi rst examinations were provided before start of pharmacotherapy and control examinations were performed from one to three weeks later when blood pressure control was provided.

RESULTS
There is possible to fi nd two diff erent situations in the group of hypertensive patients.On the one hand we can fi nd good response to started therapy and BP value in control examination in normal range.On the other hand control BP measurement reveals persistent hypertension despite of therapy and next therapeutic step is necessary.Both cases are demonstrated with their fi ndings in supine-standing-supine test.The fi rst case presents woman with good response to betablocker administration: Figures 1-3.The opposite situation demonstrates man without BP improvement after betablocking agent administration and there were three therapeutic steps necessary to achieve target BP level: Figures 4-6

Fig. 1 .
Fig. 1. 3-D graph of SA HRV during supine-standing-supine test in woman 27 years.Legend: x axis frequency (Hz), y axis power spectral density (ms/Hz), z axis time course of test T1 supine, T2 standing, T3 supine (each 300 seconds).Enhanced total spectral power and especially HF component are markedly visible.A. Before treatment BP 140/90 mmHg (therapy indication according to BP Holter monitoring).B. Control examination with blood pressure compensation on Bisoprolol 5mg daily BP 120/70 mmHg.

Fig. 4 .
Fig. 4. Graphic form of SA HRV during supine-standing-supine test.Man 39 years "non responder" to mono therapy.Therapeutic success is associated with increased spectral activity at fi nal examination -D. A. Examination before treatment BP 180/110 mmHg.B. Betaxolol 20 mg with BP 160/110 mmHg.C. Betaxolol 20 mg and Ramipril 5 mg BP 150/100 mmHg.D. Final result with BP 140/83 mmHg under control on combination of Betaxolol 20 mg and Ramipril 10mg daily.A B

Fig. 5 .
Fig. 5. Computer interpretation of ANS evaluation by method of complex parameters and indices in numeric, graphic and verbal form with so called functional age calculation.Man 39 years "non responder" to monotherapy.Changes in complex parameters during therapy with fi nal improvement of functional age parameter are demonstrated.A. Examination before treatment BP 180/110 mmHg.B. Betaxolol 20 mg with BP 160/110mmHg.C. Betaxolol 20 mg and Ramipril 5 mg with BP 150/100 mmHg.D. Final result with BP 140/83 mmHg under control on combination of Betaxolol 20 mg and Ramipril 10 mg daily.

Table 1 .
, Computer interpretation of ANS evaluation by method of complex parameters and indices in numeric, graphic and verbal form with so called functional age calculation.Woman 27 years.After BP compensation so called functional age is appropriate to calendar age. A. Before treatment.B. Woman 27 years BP compensation on Bisoprolol 5 mg daily.

Table 1 .
). Numerical form of SA HRV.Man 39 years "non responder" to monotherapy.The results demonstrate high LF/HF ratio (sympathovagal balance) and weak total spectral performance before treatment and gradual improvement of spectral performance and especially HF component (CCV HF) during therapy.