Spectral analysis of heart rate variability before and during episodes of nocturnal ischaemia in patients with extensive coronary artery disease

Eur Heart J. 1996 Mar;17(3):388-93. doi: 10.1093/oxfordjournals.eurheartj.a014870.

Abstract

Spectral analysis of heart rate variability was used to assess autonomic nervous system activity associated with episodes of nocturnal myocardial ischaemia in 32 patients (20 men, age 58 +/- 9 years) with extensive coronary artery disease. Twenty-four hour Holter tape recordings were analysed and spectral indexes of heart rate variability were computed by fast Fourier analysis on 2 min segments covering the period from 10 min before to 10 min after each nocturnal ischaemic episode, defined as ST segment depression > or = 1 mm lasting at least 4 min. Spectral power was measured at low frequencies (LF: 0.06-0.10 Hz) and high frequencies (HF: 0.15-0.40 Hz) and the ratio LF/HF was calculated. RESULTS. A total of 30 episodes of nocturnal ischaemia were analysed. High frequency spectral power showed a clear decrease during the 10 min before the onset of ischaemia, remained steady until the end of the episode, and returned to normal by 6 min after. Low frequency spectral power fluctuated throughout the ischaemic episodes with no clear pattern of variation. The low/high frequency ratio reflected mainly the changes in high frequency. CONCLUSIONS. Sympathetic predominance due to para-sympathetic withdrawal is the principal change in autonomic nervous system activity associated with episodes of nocturnal ischaemia.

MeSH terms

  • Aged
  • Autonomic Nervous System / physiopathology*
  • Circadian Rhythm*
  • Coronary Disease / physiopathology*
  • Electrocardiography, Ambulatory
  • Female
  • Fourier Analysis
  • Heart Rate / physiology*
  • Humans
  • Male
  • Middle Aged
  • Myocardial Ischemia / physiopathology*
  • Parasympathetic Nervous System / physiopathology
  • Sympathetic Nervous System / physiopathology