[Evaluation for micropotential analysis by signal-averaged ECG using Holter monitoring]

The development of signal-averaged electrocardiogram (SAECG) has made possible the examination of ventricular late potentials (LP). Recently, the Holter SAECG system, which uses the tape of Holter monitoring, was produced. In the filtered QRS duration (FQRS), a correlation of R = 0.81 was seen between real time SAE and Holter SAE. Correlation of root mean square voltage of the signals in the last 40 mS of QRS (RMS40) and the duration of low amplitude signals (< 40 microV) in the latter part of the QRS (LAS40) were 0.79 and 0.70, respectively between these two systems. As good correlation was seen among the various indicators on the Holter SAECG and real time SAECG, a comparative study in the evaluation for ventricular tachycardia (VT) was performed on these two SAECG systems. With the Holter SAECG, positive LP were as follows: in myocardial disease with VT, 83.3% were positive LP; in myocardial disease without VT, 7.5% were positive LP; and in the healthy subjects, 0% were positive LP. For assessing VT, either real time SAECG or the Holter SACGE may be considered equally suitable for clinical use. During the treadmill exercise test, myocardial ischemia was investigated by the Holter SAECG system. After exercise, healthy subjects revealed longer FQRS, larger root mean square voltage of the signals in the QRS (RMS Total). While in ischemic heart disease, that had ST depression on the Holter ECG after exercise, decrease in RMS Total was found. For assessing myocardial ischemia, it is believed that Holter SAECG had the possibility of evaluating high frequency component in the entire QRS.(ABSTRACT TRUNCATED AT 250 WORDS)