Cardiac remodeling and predictors for cardiac death in long-term follow-up of subjects with chronic Chagas' heart disease: A mathematical model for progression of myocardial damage

Abstract

In a prospective longitudinal study the occurrence of cardiac death was investigated and ongoing cardiac remodeling retrospectively analyzed in regard to adverse outcome. A cohort of 50 subjects with chronic Chagas' disease stratified according to Los Andes groups 1, 2 and 3 were followed-up for (mean ± SD) 84.2 ± 39.0 months. Follow-up was abbreviated by ventricular tachycardia ([VT] incidence: 3.0 ± 7.0% year − 1 ), first atrial fibrillation episode lasting > 24 h ([AF] incidence: 3.3 ± 1.0% year − 1 ), nonfatal embolic stroke (incidence: 1.3 ± 1.0% year − 1 ), and cardiac death (mortality rate: 2.3 ± 0.8% year − 1 ). The relative risk of Los Andes group 3, VT, AF and stroke for cardiac death was, respectively, 25.3 (95%CI [3.5–182.6]), 3.0 (95%CI [1.2–7.3]), 3.6 (95%CI [1.2–10.9]) and 1.1 (95%CI [0.2–7.2]). In a multivariate Cox proportional-hazard model, Los Andes group 3 (hazard ratio = 24.5; 95%CI [3.2–189.2]; p < 0.01) was independent predictor for cardiac death. LAD and LV mass and not LVEF variation rates differed among group 1 (respectively, 0.03 ± 0.1 cm year − 1 ; 2.4 ± 5.7 g year − 1 and − 0.1 ± 2.4% year − 1 ), group 2 (0.04 ± 0.1 cm year − 1 ; 3.7 ± 8.8 g year − 1 and − 0.8 ± 1.4% year − 1 ) and group 3 (0.13 ± 0.1 cm year − 1 , p < 0.001; 21.7 ± 10.1 g year − 1 , p < 0.001 and − 1.4 ± 2.5% year − 1 , p = 0.26). Variables on admission were linearly related to respectively variation rates ( r = 0.71; p = 0.02) composing a first order linear process with 0.07 months − 1 time constant. In chronic Chagas' disease, initial clinical status is an independent predictor for cardiac death and determines the progression rate of myocardial damage.