Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Multicenter Study
. 2012 Aug 1;5(4):719-27.
doi: 10.1161/CIRCEP.112.970541. Epub 2012 Jun 23.

Predictive value of beat-to-beat QT variability index across the continuum of left ventricular dysfunction: competing risks of noncardiac or cardiovascular death and sudden or nonsudden cardiac death

Larisa G Tereshchenko  1 , Iwona Cygankiewicz, Scott McNitt, Rafael Vazquez, Antoni Bayes-Genis, Lichy Han, Sanjoli Sur, Jean-Philippe Couderc, Ronald D Berger, Antoni Bayes de Luna, Wojciech Zareba
Affiliations
Multicenter Study

Predictive value of beat-to-beat QT variability index across the continuum of left ventricular dysfunction: competing risks of noncardiac or cardiovascular death and sudden or nonsudden cardiac death

Larisa G Tereshchenko et al. Circ Arrhythm Electrophysiol. .

Abstract

Background: The goal of the present study was to determine the predictive value of beat-to-beat QT variability in heart failure patients across the continuum of left ventricular dysfunction.

Methods and results: Beat-to-beat QT variability index (QTVI), log-transformed heart rate variance, normalized QT variance, and coherence between heart rate variability and QT variability have been measured at rest during sinus rhythm in 533 participants of the Muerte Subita en Insuficiencia Cardiaca heart failure study (mean age, 63.1±11.7; men, 70.6%; left ventricular ejection fraction >35% in 254 [48%]) and in 181 healthy participants from the Intercity Digital Electrocardiogram Alliance database. During a median of 3.7 years of follow-up, 116 patients died, 52 from sudden cardiac death (SCD). In multivariate competing risk analyses, the highest QTVI quartile was associated with cardiovascular death (subhazard ratio, 1.67 [95% CI, 1.14-2.47]; P=0.009) and, in particular, with non-SCD (subhazard ratio, 2.91 [1.69-5.01]; P<0.001). Elevated QTVI separated 97.5% of healthy individuals from subjects at risk for cardiovascular (subhazard ratio, 1.57 [1.04-2.35]; P=0.031) and non-SCD in multivariate competing risk model (subhazard ratio, 2.58 [1.13-3.78]; P=0.001). No interaction between QTVI and left ventricular ejection fraction was found. QTVI predicted neither noncardiac death (P=0.546) nor SCD (P=0.945). Decreased heart rate variability rather than increased QT variability was the reason for increased QTVI in the present study.

Conclusions: Increased QTVI because of depressed heart rate variability predicts cardiovascular mortality and non-SCD but neither SCD nor extracardiac mortality in heart failure across the continuum of left ventricular dysfunction. Abnormally augmented QTVI separates 97.5% of healthy individuals from heart failure patients at risk.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Histograms showing QTVI distribution. Histograms showing the distribution of the QTVI in healthy IDEAL subjects (empty bars) and heart failure participants of MUSIC study patients (full bars).
Figure 2
Figure 2
Survival in heart failure. Nelson-Aalen cumulative hazard estimates for the cardiovascular death (A), non-cardiac death (B), sudden cardiac death (C) and non-sudden cardiac death (D) in 4 categories of patients: those with the highest QTVI quartile and LVEF ≤35%, patients with the highest QTVI quartile and LVEF>35%, those with the lower 3 QTVI quartiles and LVEF ≤35%, patients with the lower 3 QTVI quartiles and LVEF >35%.
Figure 3
Figure 3
Cumulative incidence functions for the cardiovascular death (A), non-cardiac death (B), sudden cardiac death (C) and non-sudden cardiac death (D) in 4 categories of patients.
Figure 4
Figure 4
Kaplan-Meier curves for the probabilities of all-cause death (A), cardiovascular death (B), and sudden cardiac death (C) in patients with available QT variability results (Included), and those who were excluded from QT variability analysis as non-analyzable. Increased QT variability index (QTVI) predicts cardiovascular mortality and specifically non-sudden cardiac death, but not sudden cardiac death and not non-cardiac death in heart failure across a continuum of left ventricular dysfunction. Abnormally elevated QTVI separates 97.5% of healthy individuals from subjects at risk. Further investigation of QTVI as a potential screening tool in the general population is warranted.
See this image and copyright information in PMC

References

    1. Fang J, Mensah GA, Croft JB, Keenan NL. Heart failure-related hospitalization in the U.S., 1979 to 2004. J Am Coll Cardiol. 2008;52:428–434. - PubMed
    1. Levy D, Kenchaiah S, Larson MG, Benjamin EJ, Kupka MJ, Ho KK, Murabito JM, Vasan RS. Long-term trends in the incidence of and survival with heart failure. N. Engl. J Med. 2002;347:1397–1402. - PubMed
    1. Lloyd-Jones D, Adams RJ, Brown TM, Carnethon M, Dai S, De SG, Ferguson TB, Ford E, Furie K, Gillespie C, Go A, Greenlund K, Haase N, Hailpern S, Ho PM, Howard V, Kissela B, Kittner S, Lackland D, Lisabeth L, Marelli A, McDermott MM, Meigs J, Mozaffarian D, Mussolino M, Nichol G, Roger VL, Rosamond W, Sacco R, Sorlie P, Roger VL, Thom T, Wasserthiel-Smoller S, Wong ND, Wylie-Rosett J. Heart disease and stroke statistics--2010 update: a report from the American Heart Association. Circulation. 2010;121:e46–e215. - PubMed
    1. Liao L, Allen LA, Whellan DJ. Economic burden of heart failure in the elderly. Pharmacoeconomics. 2008;26:447–462. - PubMed
    1. The survival of patients with heart failure with preserved or reduced left ventricular ejection fraction: an individual patient data meta-analysis. European Heart Journal. 2011 - PubMed

Publication types

MeSH terms