title: Long-term stability of heart rate variability in chronic stable angina pectoris, and the impact of an acute myocardial infarction.
abstract: BACKGROUND
  Heart rate variability (HRV) reflects the balance between cardiac parasympathetic and sympathetic autonomic influences. Reduced HRV has adverse prognostic implications. The time course for changes in HRV over prolonged periods of time and the influence of an acute coronary event on HRV are not well established.
  
  
  METHODS
  Heart rate variability was assessed in patients with chronic stable angina pectoris, who were followed for 3 years within the Angina Prognosis Study in Stockholm. Patients who suffered an acute myocardial infarction after the study were re-examined after this event. We assessed HRV by the simple geometric method differential index, and traditional time- and frequency-domain measurements of HRV.
  
  
  RESULTS
  The differential index was essentially unchanged during the study (i.e. the ratio month 36/month 1 was 1.00 +/- 0.06, n = 261). Also most other time and frequency indices of HRV (SDNN, r-MSSD, SDNNIDX, total power, and VLF, LF, HF respectively; n = 63) remained largely unchanged; pNN50 and LF/HF were, however, less reproducible. In 21 patients with a subsequent acute myocardial infarction, SDNN, SDNNIDX, total power, LF and LF/HF were reduced following the event, whereas differential index, pNN50 and HF remained unchanged.
  
  
  CONCLUSIONS
  Differential index and other indices of HRV are stable and reproducible in patients with chronic stable angina pectoris. High-frequency HRV (reflecting cardiac parasympathetic activity) and the differential index changed little following an acute coronary event, and may be suitable for predictions of the future risk of sudden death even in the presence of a recent acute coronary event.
authors.affiliation: Division of Cardiovascular Medicine, Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Inge
authors.initials: I
authors.lastname: Björkander
authors.forename: Lennart
authors.initials: L
authors.lastname: Forslund
authors.forename: Mats
authors.initials: M
authors.lastname: Ericson
authors.forename: Nina
authors.initials: N
authors.lastname: Rehnqvist
authors.forename: Paul
authors.initials: P
authors.lastname: Hjemdahl
authors.forename: Thomas
authors.initials: T
authors.lastname: Kahan
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000368:Aged; D000787:Angina Pectoris / Q000188:drug therapy / Q000209:etiology / Q000401:mortality / Q000503:physiopathology*; D002121:Calcium Channel Blockers / Q000627:therapeutic use; D002908:Chronic Disease; D003324:Coronary Artery Disease / Q000150:complications / Q000188:drug therapy / Q000401:mortality / Q000503:physiopathology*; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000627:therapeutic use; D008875:Middle Aged; D008955:Models, Cardiovascular; D009203:Myocardial Infarction / Q000209:etiology / Q000401:mortality / Q000503:physiopathology*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D018570:Risk Assessment; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D014700:Verapamil / Q000627:therapeutic use
chemical_list: D000319:Adrenergic beta-Antagonists; D002121:Calcium Channel Blockers; D014700:Verapamil; D008790:Metoprolol