A New T‐wave Frequency Based Index for Discrimination of Abnormal Repolarization

Aim of the present study was to propose an innovative TCE10 index (defined as the T-wave cumulative normalized energy at 10 Hz, in %) as a useful tool to characterize the T wave in terms of its frequency content, and to test the TCE10 ability to discriminate abnormal cases of repolarization. To this aim, ECG recordings (X, Y, Z leads and vector-magnitude signal, VMS) of 23 control healthy (CH) subjects and 23 antero-septal acute myocardial infarction (ASAMI) patients were analysed. Abnormal repolarization was identified when TCE10 was below a threshold value, defined as the 25th percentile of the TCE10 distribution over the CH population. Results indicate that the ASAMI population was characterized by lower TCE10 values than the CH population (X: 93.9 +/- 5.9% vs. 98.2 +/- 1.2%; Y: 95.2 +/- 4.5% vs. 97.8 +/- 1.4%; Z: 97.4 +/- 1.6% vs. 99.1 +/- 1.5%; VMS: 95.7 +/- 2.8% vs. 97.9 +/- 1.3%; P<0.01). Moreover, the ASAMI patients were discriminated from the CH subjects with a lead-independent specificity of 74% and a lead-dependent sensitivity of 78%, 61%, 87% and 57% for lead X, Y, Z and VMS, respectively. In conclusion, compared to the CH subjects, the ASAMI patients show increased high-frequency spectral energy and were discriminated from the former with satisfactory values of sensibility and specificity.