| Autor: |
Steinbigler, Peter, Haberl, Ralph, Schmücking, Ingo, Dorwarth, Uwe, Mattke, Sören, Hoffmann, Ellen, Steinbeck, Gerhard |
| Zdroj: |
Annals of Noninvasive Electrocardiology; Jan1997, Vol. 2 Issue 1, p9-19, 11p |
| Abstrakt: |
Objective: Exercise induced ischemia or heart rate acceleration may unmask late potentials or provoke functional changes, which might be important factors to improve the low positive predictive value of late potential analysis at rest for postinfarction risk stratification. However, methodological refinements are required to detect late potentials with exercise. Methods: We, therefore, investigated the surface-electrocardiogram in 100 patients after myocardial infarction (50 with sustained ventricular tachycardia [group I], 50 patients without ventricular arrhythmias [group II], and in 15 normals before and immediately after bicycle exercise test using Spectrotemporal Mapping (STM) with fast Fourier transform (FFT) and Simson method and introduced selective signal averaging. Results: In group I, 30 out of 50 patients showed late potentials at rest, after selective signal averaging also recognizable immediately after exercise in all of these patients, however, with a time-shift of 18 ± 13 ms into the ST-segment. Twelve out of 50 patients of group I with only transient late potentials tended to have inducible and recurrent ventricular tachycardia with a shorter cycle length. In group II, 4 out of 50 patients had late potentials at rest and 2 out of 46 patients developed them during exercise. Transient pathological Simson method was associated with transmural ischemia. Conclusions: Thus, detection of the effects of exercise on late potential analysis is possible with selective signal averaging immediately after exercise. Exercise unmasks late potentials not detectable at rest by their time-shift into the ST-segment. Using this method, patients that would have been lost with conventional late potential analysis, could be identified. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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