Abstract:
In the present Thesis some, aspects of T-wave morphology are considered for characterization and quantification of heterogeneous repolarization, using the Vectorcardiogram (VCG) implemented in LabVIEW. The orthogonal Frank leads were synthesized from the standard 12 lead ECG. Several methods for synthesizing Frank VCG's from simultaneously recorded 12 standard leads has been studied and concluded that either a regression technique or a method based on the reverse of Dower's approach provide the best solution. From the derived X, Y, and Z leads, ventricular repolarization is defined from the start of S index to end of the cycle. The subtle changes in the course of T wave loop, possibly reflecting sudden changes in repolarization wave front is analyzed with the help of three parameters obtained from the VCG with two different methods of considering the zero point. The parameters are calculated for each cycle of waveform and averaged excluding the first and last detected R peaks. The obtained T—loop morphology parameters is studied on myocardial infarction and ischemia data sets and healthy database from the 'PTB diagnostic database' consisting of 15 lead data. The limits of the parameters of the healthy (42) from the myocardial patients (58) is distinguished. Cross-comparison between healthy and the myocardial groups is performed with t-test for all the parameters to evaluate the differences in mean between the two groups.
