[Changes in heart rate variability after myocardial infarction. Value of Poincareé's diagram].
The variability of the heart rate is reduced after myocardial infarction. It then progressively increases, to return to near normal values after several months. However, these changes in heart rate variability occur at the same time as slowing of the heart rate which makes interpretation difficult. Poincaré's diagram is constructed from a Holter recording plotting each RR interval against the preceding RR interval. The authors have developed a geometric approach to this diagram to evaluate parasympathetic tone for a given heart rate. By measuring the dispersion in height of the Poincaré's diagram, the authors evaluate the shor-term variability for a given RR interval. Two 24 hr Holter recordings were performed in 52 patients at one and two weeks after a myocardial infarction. The dispersion in the height of the Poincaré's diagrams was measured at the 10th, 25th, 50th, 75th and 90th percentiles of the total dispersion. The authors have shown an increase in the short-term variability of the shortest RR intervals (1th, 25th and 50th percentiles) which is not observed in the longer RR intervals (75th and 90th percentiles). In conclusion, theres is an increase in the heart rate variability at the shortest RR intervals. This suggests that the recovery of parasympathic tone after myocardial infarction occurs mainly at the fastest heart rates.
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Département de cardiologie, INSERM U256, hôpital Broussais, Paris.
Le Heuzey
J Y
JY
Iliou
M C
MC
Pousset
F
F
Lavergne
T
T
Guize
L
L
D000368:Aged; D015716:Electrocardiography, Ambulatory / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006339:Heart Rate; D006801:Humans; D016018:Least-Squares Analysis; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009203:Myocardial Infarction / Q000503:physiopathology*; D010275:Parasympathetic Nervous System / Q000503:physiopathology; D011237:Predictive Value of Tests; D011379:Prognosis; D012016:Reference Values; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors
Evolution de la variabilité de la fréquence cardiaque après infarctus du myocarde. Apport du diagramme de Poincaré.