High frequency QRS components: A comparative analysis to assess myocardial damage in chronic chagasic patients

The aim of this work was to assess the effect of high-frequency QRS (HF-QRS) components over different bandwidths and leads as a method to discern myocardial damage in a chronic Chagas disease cohort. We analysed 96 Chagasic subjects divided into three groups according to their cardiomyopathy damage degree and 11 healthy subjects. Signal-averaged ECG was obtained for each orthogonal lead (X-Y-Z) as well as the cardiac vector. Four bandwidths were proposed in the analysis: 80–300Hz, 150–250 Hz, 40–80 Hz, and 40–300Hz. HF-QRS components were quantified in each bandwidth as the root-mean-square value of the filtered signals among the QRS endpoints (X-Y-Z and the cardiac vector were individually assessed). Groups were compared using the Mann-Whitney ‘U’ test. A ROC curve analysis was conducted for each feature reflecting statistical significance (p<0.05) and area under the curve values (AUC) were compared. HF-QRS activity decreases as cardiac damage degree increases. All group comparison evidenced statistical significance. Overall, the main effect was observed in 40–300 Hz (Y-lead), the bandwidth (channel) that achieved the highest AUC values when discerning among groups. These results suggest HF-QRS could monitor cardiac damage progression in chronic Chagasic cardiomyopathy.