By analysis of spectral components of heart rate variability, sympathovagal interaction was assessed in patients after acute myocardial infarction (AMI). At 2 weeks after AMI (n = 70), the low-frequency component was significantly greater (69 +/- 2 vs 53 +/- 3 normalized units [NU], p less than 0.05) and the high-frequency component was significantly smaller (17 +/- 1 vs 35 +/- 3 NU) than in 26 age-matched control subjects. This difference was likely to reflect an alteration of sympathovagal regulatory outflows with a predominance of sympathetic activity. At 6 (n = 33) and 12 (n = 29) months after AMI, a progressive decrease in the low- (62 +/- 2 and 54 +/- 3 NU) and an increase in the high-frequency (23 +/- 2 and 30 +/- 2 NU) spectral components was observed, which suggested a normalization of sympathovagal interaction. An increase in sympathetic efferent activity induced by tilt did not further modify the low-frequency spectral component (78 +/- 3 vs 74 +/- 3 NU) in a subgroup of 24 patients at 2 weeks after AMI. Instead, 1 year after AMI, this maneuver was accompanied by an increase in the low-frequency component (77 +/- 3 vs 53 +/- 3 NU, p less than 0.05) of a magnitude similar to the one observed in control subjects (78 +/- 3 vs 53 +/- 3 NU). These data indicate that the sympathetic predominance that is detectable 2 weeks after AMI is followed by recovery of vagal tone and a normalization of sympathovagal interaction, not only during resting conditions, but also in response to a sympathetic stimulus.
Heart rate variability as an index of sympathovagal interaction after acute myocardial infarction / F. Lombardi, G. Sandrone, S. Pernpruner, R. Sala, M. Garimoldi, S. Cerutti, G. Baselli, M. Pagani, A. Malliani. - In: THE AMERICAN JOURNAL OF CARDIOLOGY. - ISSN 0002-9149. - 60:16(1987), pp. 1239-1246.
|Titolo:||Heart rate variability as an index of sympathovagal interaction after acute myocardial infarction|
LOMBARDI, FEDERICO (Primo)
PAGANI, MASSIMO (Penultimo)
MALLIANI, ALBERTO (Ultimo)
|Settore Scientifico Disciplinare:||Settore MED/11 - Malattie dell'Apparato Cardiovascolare|
|Data di pubblicazione:||1987|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/0002-9149(87)90601-1|
|Appare nelle tipologie:||01 - Articolo su periodico|