Abstract 19759: A Novel Risk Score Based on Noninvasive ECG Monitoring Aiming at Predicting Ventricular Tachycardia and Cardiac Death in Chronic Chagas Disease
Introduction: Cardiac arrhythmia is a major cause of death in chronic Chagas disease (CCD). We prospectively investigated 12-lead resting, signal-averaged (SAECG) and ambulatory ECG in CCD as predictors of a composite of new onset ventricular tachycardia (VT) and cardiac death.
Methods: Clinically stable outpatients with CCD (34 to 74 y.o, 38 males) staged according to Los Andes (Class I: N=28; II: N=48; III: N=24) were enrolled, and initially submitted to 12-lead resting ECG, time and frequency domain analysis of SAECG, and 24h ambulatory ECG assessing, respectively: 1) pathological Q waves ([Q-wave] fibrosis); 2) filtered QRS duration ([QRSf] IVCD); 3) spectral turbulence analysis ([STA] reentry mechanism), 4) 24h SD of normal RR intervals ([SDNN] autonomic function) and VT (arrhythmic event). During follow-up, ambulatory ECG assessed new onset VT. Deaths were ascertained by review of medical records. Cox proportional hazard model identified predictors for a composite of new onset VT and cardiac death. Continuous variables are presented as mean±SEM and discrete ones as percentage.
Results: During a mean 95.3 months follow-up, 36 subjects had events: 22 new onset VT (18.4±0.9‰/year) and 20 deaths (26.4± .4‰/year). In univariate analysis, Q-wave (p=0.002); QRSf>150ms (p=0.002), high STA (p=0.001), SDNN<100ms (p<0.001) and VT (p<0.001) were predictors for composite endpoint. In multivariate analysis, Q-wave (p<0.001), high STA (p=0.04); SDNN<100ms (p=0.002) and VT (p<0.001) were independent predictors (Table inset). A prognostic score was developed by rounding weighted points proportional to beta coefficients in Cox model. ROC analysis optimized cutoff value at >1. KM curves are presented in Figure A. In 1,000 bootstraps, c-statistic of novel score was superior to Rassi score (Figure B).
Conclusions: In CCD, Q-wave, high STA, cardiac autonomic dysfunction and previous VT episode are independent predictors for a composite of new onset VT and cardiac death.
- Ventricular tachycardia
- Signal averaging
- Heart rate/Heart rate variability
- © 2010 by American Heart Association, Inc.