Author + information
- Mark Haigney,
- Craig P. Dobson,
- Maria Teresa La Rovere,
- Gian Domenico Pinna,
- Cara Olsen,
- Robert Goldstein,
- Marco Gorini,
- Marino Bernardinangeli and
- Luigi Tavazzi
Repolarization lability, assessed as QT Variability Index (QTVI), is associated with increased mortality risk in chronic heart failure (HF). Whether QTVI remains stable over time and whether added measurements increase predictive power remain uncertain.
GISSI-HF prospectively enrolled subjects with HF of any cause. Of 372 24-hour digital recordings at enrollment, 275 were suitable for analysis. Recordings were repeated 3 and 12 months later. QTVI = log ratio (normalized QT variance/normalized heart rate variance).
167 subjects had follow-up recordings at 3 months and 19 also at 12 months; 55 died (44 cardiovascular). QTVI remained very stable for individuals over time: entry QTVI correlated significantly with replicates at 3 months (−1.029 vs −1.037, r=0.54, p <0.0001) and 12 months (−1.061 (r=0.65, p=0.01). QTVI over 12 months was linked to increased mortality as a continuous variable (HR 3.8, Cl 1.9-7.6, p =0.0001), dichotomized at the highest quartile QTVI > −0.84 (HR 2.5, Cl 1.4-4.4, p=0.001) or dichotomized at QTVI > −0.50 (HR 3.3, Cl 1.5-7.0, p=0.0018, see figure). QTVI predicted total mortality (HR 3.5, Cl 1.7-7.2, p=0.0004) in a multivariate model including age, prior ventricular tachycardia, creatinine and ejection fraction.
In this first evaluation of QTVI reproducibility, individual values for QTVI remained remarkably stable over 3 and 12 months. In multivariate analysis, QTVI was a highly significant independent predictor of total mortality.
Poster Sessions, Expo North
Saturday, March 09, 2013, 10:00 a.m.-10:45 a.m.
Session Title: New Diagnostic and Imaging Strategies in Heart Failure
Abstract Category: 15. Heart Failure: Clinical
Presentation Number: 1136-299
- 2013 American College of Cardiology Foundation