Abstract 351: Nonlinear Dynamics in Long-Term Left Ventricular Remodeling in Chagas Heart Disease and Adverse Outcomes: SEARCH-Rio Substudy

Abstract

Introduction: Left ventricular (LV) remodeling in Chagas heart disease (CHD) depends on the severity of the initial insult and may have clinical implication. SEARCH-Rio study investigated nonlinear dynamics in long-term LV remodeling in CHD. Methods: Fifty stable outpatients with CHD were enrolled and followed at scheduled visits. Cardiac death (sudden, arrhythmic or heart failure) was ascertained by review of medical records. LV dimension was assessed by echocardiogram, and mass estimated by Devereux. Subjects were distributed in four equally spaced groups according to initial mass. Intra-group standard deviation (SD) was calculated throughout follow-up. A plot of LV mass (corrected to initial value) vs recurrences during follow-up assessed non-linear relationship. Lyapunov exponent (LE) assessed LV mass dynamics during follow-up. Results: Median follow-up was 95 months; 10 subjects died. LV mass groups were [mean; Figure 1]: I-110g, II-140g, III-170g, IV-200g. No inter-group SD differences at baseline were observed (p=NS; table inset). At end of follow-up, intra-group SD increased roughly proportional to initial mean LV mass (Figure 1; p=0.01). A logistic parabolic-shaped equation was fit to corrected LV mass data in the plot (r²=0.98) and alpha coefficient was 3.9 (p<0.01; Figure 2). In groups, median LE was: I: 0.22; II: 0.17; III: 0.22; IV: 0.15. Median LE was 0.7 for survivors and -0.45 for nonsurvivors. LE cutoff at 0.26 yielded 100% sensitivity and 88% specificity for cardiac death (AUC=0.89; p<0.01). Conclusion: In CHD, LV remodeling exhibits complex nonlinear dynamics. LV remodeling dynamics has prognostic implication in this population.