G. Schmidt et al., Heart-rate turbulence after ventricular premature beats as a predictor of mortality after acute myocardial infarction, LANCET, 353(9162), 1999, pp. 1390-1396
Citations number
32
Categorie Soggetti
General & Internal Medicine","Medical Research General Topics
Background Identification of high-risk patients after acute myocardial infa
rction is essential for successful prophylactic therapy. The predictive acc
uracy of currently used risk predictors is modest even when several factors
are combined. Thus, establishment of a new powerful method for risk predic
tion independent of the available stratifiers is of considerable practical
value,
Methods The study investigated fluctuations of sinus-rhythm cycle length af
ter a single ventricular premature beat recorded in Holter electrocardiogra
ms, and characterised the fluctuations (termed heart-rate turbulence) by tw
o numerical parameters, termed turbulence onset and slope. The method was d
eveloped on a population of 100 patients with coronary heart disease and bl
indly applied to the population of the Multicentre Post-Infarction Program
(MPIP; 577 survivors of acute infarction, 75 deaths during a median follow-
up of 22 months) and to the placebo population of the European Myocardial A
miodarone Trial (EMIAT; 614 survivors of acute myocardial infarction, 87 de
aths during median follow-up of 21 months). Multivariate risk stratificatio
n was done with the new parameters and conventional risk factors.
Findings One of the new parameters (turbulence slope) was the most powerful
stratifier of follow-up mortality in EMIAT and the second most powerful st
ratifier in MPIP: MPIP risk ratio 3.5 (95% CI 2.2-5.5, p<0.0001), EMIAT ris
k ratio 2.7 1.8-4.2, p<0.0001), In the multivariate analysis, low left-vent
ricular ejection fraction and turbulence slope were the only independent va
riables for mortality prediction in MPIP (p<0.001), whereas in EMIAT, five
variables were independent mortality predictors: abnormal turbulence onset,
abnormal turbulence slope, history of previous infarction, low left-ventri
cular ejection fraction, and high mean heart rate (p<0.001). In both MPIP a
nd EMIAT, the combination of abnormal onset and slope was the most powerful
multivariate risk stratifier: MPIP risk ratio 3.2 (1.7-6.0, p<0.0001), EMI
AT risk ratio 3.2 (1.8-5.6, p<0.0001).
Interpretation The absence of the heart rate turbulence after ventricular p
remature beats is a very potent postinfarction risk stratifier that is inde
pendent of other known risk factors and which is stronger than other presen
tly available risk predictors.