Session S54.1

Improving Reliability of Total-Cosine-R-to-T (TCRT) in Patients with Acute Myocardial Infarction

M Karsikas*, H Huikuri, T Seppänen

University of Oulu
Oulu, Finland

The parameter TCRT (Total Cosine R-to-T) calculated from ECG recording has been shown to have a remarkable prognostic value as a predictor of the outcomes of the coronary artery disease and the post-myocardial infarction patients. Especially depressed TCRT has been strongly associated with increased cardiac mortality after acute myocardial infarction (AMI). The TCRT is conventionally calculated using an algorithm produced by Acar et al. (1999). In this study, the reliability of the TCRT algorithm was tested with the ECG data of the healthy group (n=25) and the AMI group (n=45). Typical ECG changes such as inverted and symmetrical T waves, ST elevations, wide QRS complex, and reduction of the R wave, occurred in the AMI group. Calculation of TCRT failed in several AMI cases due to severe segmentation problems with the ECG waves. Typical problems occurred in the detection of the maximum of the T vector (9% of patients), the bounding of the R wave (18%), a comprehensive segmentation (11%) and a decreased congruence between TCRT and the spatial QRS-T angle (33%). The results show that small improvements to the basic algorithm can decrease the number of failures up to 82% in AMI data. The improvements included: resetting of threshold values, better detection of the T peak, and a more accurate model of the de-/repolarization sequence. It is concluded that segmentation properties should be improved in the basic TCRT algorithm in order to maintain the diagnostic value of TCRT in different patient data.

(Abstract Control Number: 60)