Vol 3, No 3 (1999)
REVIEV
Published online: 2000-03-09
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Heart Rate Variability in a Hypertension Aspect - Basic Mechanisms and their Assessment by Means of Fourier Transformation

Ewa Czyżewska, Marek Marcinkiewicz
Nadciśnienie tętnicze 1999;3(3):200-207.
Vol 3, No 3 (1999)
REVIEV
Published online: 2000-03-09

Abstract

An impairment of cardiovascular autonomic regulation plays an important role in pathogenesis of cardiac sudden death. Altered autonomic modulation of heart rate in systemic hypertension is mainly due to elevated blood pressure. Evidence has been provided that both the baroreceptor reflex control of heart rate and the variability of the R-R interval (HRV) during sinus rhythm may be impaired in long-standing hypertension. The baroreflex is reset to operate at higher arterial pressure levels and has a reduced sensitivity to dynamic changes in arterial pressure. This results in a diminished R-R interval and reduced HRV However, an objective assessment of HRV is possible by means of spectral analysis (based on Fourier transformation) used to detect rhythmic variations .in a record of successive R-R intervals by decomposing the record into series of sinusoidal functions of different frequencies. This methodological approach results in the spectral-density function (PSD) which describes the variability of R-R intervals and its distribution with regard to frequency. In patients with longstanding hypertension reduced low-frequency spectral components of HRV are associated with an increased risk of life threatening arrhythmias and cardiac mortality. In patients with borderline hypertension, low-frequency components of HRV are higher and low-frequency components are lower than normal suggesting that autonomic modulation of heart rate is different in borderline hypertension than in long-standing disease. It is not known, however, whether the observed abnormal cardiovascular autonomic regulation is a primary feature related to systemic hypertension and precedes the onset of hypertension.

Abstract

An impairment of cardiovascular autonomic regulation plays an important role in pathogenesis of cardiac sudden death. Altered autonomic modulation of heart rate in systemic hypertension is mainly due to elevated blood pressure. Evidence has been provided that both the baroreceptor reflex control of heart rate and the variability of the R-R interval (HRV) during sinus rhythm may be impaired in long-standing hypertension. The baroreflex is reset to operate at higher arterial pressure levels and has a reduced sensitivity to dynamic changes in arterial pressure. This results in a diminished R-R interval and reduced HRV However, an objective assessment of HRV is possible by means of spectral analysis (based on Fourier transformation) used to detect rhythmic variations .in a record of successive R-R intervals by decomposing the record into series of sinusoidal functions of different frequencies. This methodological approach results in the spectral-density function (PSD) which describes the variability of R-R intervals and its distribution with regard to frequency. In patients with longstanding hypertension reduced low-frequency spectral components of HRV are associated with an increased risk of life threatening arrhythmias and cardiac mortality. In patients with borderline hypertension, low-frequency components of HRV are higher and low-frequency components are lower than normal suggesting that autonomic modulation of heart rate is different in borderline hypertension than in long-standing disease. It is not known, however, whether the observed abnormal cardiovascular autonomic regulation is a primary feature related to systemic hypertension and precedes the onset of hypertension.
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Keywords

heart rate variability; hypertension; Fourier transformation; autonomic nervous system

About this article
Title

Heart Rate Variability in a Hypertension Aspect - Basic Mechanisms and their Assessment by Means of Fourier Transformation

Journal

Arterial Hypertension

Issue

Vol 3, No 3 (1999)

Pages

200-207

Published online

2000-03-09

Bibliographic record

Nadciśnienie tętnicze 1999;3(3):200-207.

Keywords

heart rate variability
hypertension
Fourier transformation
autonomic nervous system

Authors

Ewa Czyżewska
Marek Marcinkiewicz

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