Spatial repolarization heterogeneity and survival in Chagas disease

We investigate if cardiac spatial repolarization heterogeneity is related to the risk of death in a population of chronic Chagas disease patients. Repolarization heterogeneity was assessed using the V–index, a recently introduced metric founded on a biophysical model of the ECG. This metric provides an estimate of the standard deviation of the repolarization times across the heart. We analyzed 113 patients (aged 21-67 years) enrolled between 1998 and 1999 who had a known serological status showing a positive reactions to Trypanosoma cruzi. 14 subjects died before the end of the study. The V–index was significantly lower in survivor (S) than in non–survivor (NS) subjects (S: 31.2±13.3 ms vs. NS: 41.2±18.6 ms,p=0.018, t-test). A Vindex larger than 36.3 ms was related to a significantly higher risk of death in an univariate Cox proportional-hazards analysis (hazard ratio, HR = 5.34, p=0.0046).