title: [Variability of the heart rate and silent ischemia after myocardial infarction].
abstract: OBJECTIVE
  To show a possible relation between heart rate and silent myocardial ischemia.
  
  
  METHODS
  Forty-nine ischemic episodes were registered in six patients during a total period of 576-hour Holter monitoring. Those patients were selected from a group of 40 asymptomatic individuals after a first uncomplicated myocardial infarction; 11 (27.5%) showed ischemia during daily activities or exercise, the six selected patients had myocardial ischemia on Holter monitoring.
  
  
  RESULTS
  The silent episodes consisted 92% of the total ischemic burden; they lasted from 1 min 30 s to 20 min and the ST-segment depression varied from -1.1 mm to 3.3 mm. Thirty-five (72%) episodes occurred at rest or during light physical activities; nine (18.5%) occurred between 7:00 AM and 12:00 PM; eight (16.5%), between 12:00 PM and 6:00 PM; 17 (35%) between 6:00 PM and 12:00 AM and 15 (30%), between 12:00 AM and 7:00 AM. There was no significant change (more than 20%) in heart rate at the onset of ischemic episodes in relation to the heart rate 1 minute before (94.63 +/- 9.79 bpm and 99.47 +/- 10.99 bpm, respectively). Complex ventricular arrhythmias occurred in all patients and only one of them had an episode of nonsustained ventricular tachycardia related to silent ischemia.
  
  
  CONCLUSIONS
  Our results suggest that there is no relation between heart rate, arrhythmias and silent ischemia.
authors.affiliation: Instituto do Coração do Hospital das Clínicas, FMUSP.
authors.forename: M C
authors.initials: MC
authors.lastname: Solimene
authors.forename: J A
authors.initials: JA
authors.lastname: Ramires
authors.forename: C J
authors.initials: CJ
authors.lastname: Gruppi
authors.forename: S F
authors.initials: SF
authors.lastname: de Oliveira
authors.forename: P L
authors.initials: PL
authors.lastname: da Luz
authors.forename: F
authors.initials: F
authors.lastname: Pileggi
mesh_terms: D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D003327:Coronary Disease / Q000503:physiopathology*; D015716:Electrocardiography, Ambulatory; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology*
vernacular_title: Variabilidade da freqüência cardíaca e isquemia silenciosa após infarto do miocárdio.