Circadian variation of the myocardial ischemic threshold in patients with ischemic heart disease

Eiji Ino-Oka, Hiroshi Sekino, Yasuaki Ohtaki, Hikaru Inooka, Kouichi Sagawa, Junichirou Hashimoto, Yutaka Imai

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Purpose. Circadian variation of the heart rate (HR) at the myocardial ischemic threshold was compared with that of the HR at the sympathetic tone threshold in 16 cases of effort angina pectoris. Methods. The high (0.15-0.40 Hz, Hf) and low (0.03-0.15 Hz, Lf) frequency spectral components were extracted every twenty seconds, using frequency domain analysis of the RR interval recorded by a 24-hour Holter ECG with an accelerometer. HR-Hf data collected every five minutes were plotted as the X-Y coordinates, and a two-compartment analysis was performed. The HR at the autonomic tone threshold was then determined at the intersection point of the lines. A loop of the HR-ST segment was drawn during walking to determine the ischemic threshold at which heart rate ischemic ST segment depression began and circadian variation was observed. Results. The circadian rhythm at the sympathetic tone threshold and the HR at the ischemic threshold were high during the day and low at night. The HR at the ischemic threshold was 15-20% higher than that at the sympathetic tone threshold at night but only 9-13% higher during the day. Also, there was a period during which there was no significant difference between the HR at the two thresholds. Conclusion. In comparing circadian variation between HR at the sympathetic tone threshold and HR at the ischemic threshold, there was a period during which there was no significant difference between the HRs. This might suggest a period in which a high incidence of cardiac ischemic attack is likely. This information could provide a feasible indicator for appropriate exercise training for patients with ischemic heart disease.

Original languageEnglish
Pages (from-to)3-12
Number of pages10
JournalClinical and Experimental Hypertension
Volume29
Issue number1
DOIs
Publication statusPublished - 2007 Jan

Keywords

  • Ambulatory ECG
  • Daily fluctuation
  • Ischemic threshold
  • Sympathetic nerve activity

ASJC Scopus subject areas

  • Internal Medicine
  • Physiology

Fingerprint Dive into the research topics of 'Circadian variation of the myocardial ischemic threshold in patients with ischemic heart disease'. Together they form a unique fingerprint.

  • Cite this