To confirm health condition of considered healthy subjects, their QRST integral maps were compared with available template (obtained from 72 healthy people measured in 32 leads according to Lux (4)) and departure QRST integral maps representing deviations from QRST integral map template were computed.
Difference QRST integral maps (DI maps) as a difference between reference QRST integral map of record 0 and QRST integral maps of each record after nitroglycerine application were computed.
Inverse method was based on the presumption that small ischemic lesion creates additional generator responsible for changes in surface QRST integral map that can be represented by a single current dipole.
Although all departure maps had negative extremes greater than 2 standard deviations, departure maps of group A achieved extremes smaller than 3 standard deviations while departure maps of group B had extremes larger then 3 standard deviations from QRST integral map template.
In the group of arrhythmia patients, QRST integral map variability amplitudes increased significantly compared to the healthy group, while the random character of the pattern changes persisted.
Similarly, in normal subjects the autocorrelation functions of the KL components revealed a respiration dependent integral map pattern modulation.
Correlation matrices of QRST integral map coefficients (Only the first 6 KL coefficient correlations of the patients shown in Figure 1 are presented) KL1 KL2 KL3 KL4 KL5 KL6 KL1 1.
For the detailed quantitative representation of beat-to-beat spatial repolarization patterns, QRST integral maps and difference maps (indicating departure from the average integral distributions) were drawn.
Usefulness of the QRST integral maps to detect vulnerability to malignant arrhythmias in patients with old myocardial infarction.
In patients with previous anterior and inferior myocardial infarction the same authors demonstrated that (IRS integral maps enabled a precise localization of the origin of postinfarction VT in 62% and regional approximation (identification of a segment immediately adjacent to the actual endocardial segment of origin) in 30%of tachy cardias (13).
We found thatthe percent contribution of non-dipolar eigenvectors (all eigenvectors beyond the third) to integral maps was significantly higher in LOTS patients than in normals (6).
Because the nondipolar content did not perform well in their study population, the authors examined how individual eigenvector pattern contributes to QRST integral maps in each group of patients.