Heart rate variability: A contribution to a better understanding of the clinical role of heart rate

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Abstract

Analysis of heart rate variability (HRV) has been proved effective in the assessment of autonomic tone and in risk stratification after myocardial infarction. The negative predictive value of a reduced HRV has been associated with an altered autonomic balance characterized by signs of sympathetic activation and of a reduced vagal tone. In normal subjects, heart rate and HRV are inversely correlated. This relationship, however, is altered and sometimes no longer present in several clinical conditions associated with signs of sympathetic activation. In these patients, when resting heart rate and HRV are essentially normal, spectral analysis of HRV facilitated the appraisal of an abnormal autonomic modulation of sinus node. Conversely, when heart rate is increased and HRV is drastically reduced, the spectral profile is characterized by a marked attenuation of the low and high frequency component, with most of the residual power distributed within the very low frequency range. This picture, that can be detected after a complicated myocardial infarction or in the more advanced phases of cardiac failure, is considered to reflect diminished responsiveness of the sinus node to neural modulatory inputs and has been associated with a more negative prognosis. Thus, analysis of HRV map provide information on autonomic modulation of sinus node, in addition to that derivable by considering instantaneous heart rate, and may facilitate the appraisal of the specific contribution of sympathetic and vagal mechanisms controlling sinus node function.

Original languageEnglish
JournalEuropean Heart Journal, Supplement
Volume1
Issue numberH
Publication statusPublished - 1999

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Keywords

  • Autonomic nervous system
  • Spectral analysis
  • Sudden death
  • Sympathetic activation

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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