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Low frequency spectral component of heart rate variability and myocardial beta-adrenoceptor density after acute

Stefano Guzzetti1, Nicos Spyrou, Stuart D Rosen

  • 1Università degli Studi Milano, Italy.

Basic Research in Cardiology
|May 10, 2002
PubMed

Insights

The blunted day-night pattern of the low frequency (LF) component of heart rate variability (HRV) in post-myocardial infarction (MI) patients indicates sustained sympathetic over-activity. This loss of oscillation is linked to reduced myocardial beta-adrenoceptor density.

Area of Science:

  • Cardiology
  • Autonomic Nervous System Research
  • Physiology

Background:

  • The low frequency (LF) spectral component of heart rate variability (HRV) typically reflects sympathetic nervous system activity.
  • In cardiovascular diseases, a blunted 24-hour pattern of the LF component is often observed.
  • The relationship between sympathetic drive and LF component patterns in non-physiological conditions requires further investigation.

Purpose of the Study:

  • To examine the association between chronic sympathetic efferent drive, indicated by myocardial beta-receptor density, and the 24-hour LF spectral component power in patients post-acute myocardial infarction (AMI).

Main Methods:

  • Heart rate variability (HRV) was analyzed over 24 hours in 24 post-AMI patients one month after uncomplicated Q wave MI.
  • Time domain measures (SDNN, SDANN) and spectral components (VLF, LF, HF) were calculated.
  • Myocardial beta-adrenoceptor density was quantified using in vivo positron emission tomography (PET) with 11-CGP-12177.

Main Results:

  • Post-AMI patients exhibited reduced myocardial beta-adrenoceptor density despite normal plasma catecholamine levels.
  • Patients showed lower SDNN and SDANN values compared to controls, with a blunted day-night oscillation in LF spectral component power.
  • A significant positive correlation was found between the day-night change in LF spectral component power and myocardial beta-adrenoceptor density (r = 0.51; p < 0.001).

Conclusions:

  • The diminished day-night oscillation of the LF spectral component is a significant indicator of sustained sympathetic over-activity in patients following AMI.
  • This finding highlights the potential of HRV analysis to assess autonomic dysfunction post-myocardial infarction.
Abstract

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