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Seventy-nine patients with angiographically documented coronary artery disease were studied with exercise ECG and Holter ECG for ischaemic ST segment changes. Fifty-four patients (68.3%) had ischaemia on exercise, 48 patients (62.0%) had ischaemic ST segment depression during Holter monitoring. Twenty-four (30%) of the patients with a positive exercise test and 30 (61%) with a positive Holter ECG were asymptomatic during the test, 83.7% of the total count of 456 episodes of spontaneous ischemia during Holter monitoring were silent. Forty-four patients (55.7%) had ischaemic ECG changes during exercise and Holter ECG, 20 patients (25.3%) were negative on both tests. Ten (12.7%) had only a positive exercise test and five (6.3%) only a positive Holter ECG. The sensitivity of Holter monitoring for the detection of ischaemia in patients with coronary artery disease is comparable to the sensitivity of the exercise ECG.

The analysis of ST segment changes during Holter monitoring is one important diagnostic method for detection and diagnosis of silent myocardial ischaemia. To assess the specificity and sensitivity of ST segment alterations as a diagnostic tool, 106 healthy medical students (43 females, 57 males, aged 18-36 years, mean age 26 +/- 4 years) and 26 children (14 females, 12 males, aged 12-17 years, mean 14 +/- 3 years) with no history of heart disease and normal findings during physical examination were studied by exercise stress test and Holter monitoring. Criteria for exclusion were a history of hypertension, diabetes mellitus and ST segment alterations during conventional 12-lead ECG. Due to these criteria, eight volunteers had to be excluded from the study. The exercise stress test (maximum work load protocol) revealed no pathological ST segment depressions. During Holter monitoring seven episodes of ST segment depressions (greater than or equal to 1.0 mm planar or downsloping, duration greater than or equal to 1.0 min) were found. Typical ST segment depressions detected by Holter monitoring may be found in healthy subjects. Therefore this finding has to be considered cautiously as a diagnostic tool for evaluation of patients with suspected coronary heart disease.

On the occasion of a routine medical check-up 256 out of 1100 individuals with an accumulation of coronary risk factors were screened for silent myocardial ischaemia by exercise testing and Holter monitoring. Of these individuals 5.5% had a pathological exercise test, 7.4% had ischaemia-like events on the Holter ECG, 11.3% had at least one pathological test, but only 1.6% had ischaemic signs in both ECG tests. The outcome of the ECG tests appears to be independent of the type and the total number of risk factors. To date, 13 of the 29 individuals with a positive test have undergone thallium myocardial imaging: only three individuals had signs of ischaemia. Holter monitoring and exercise ECG show comparable results in this population. The pathological ECG findings were only partly confirmed by the thallium test. The follow-up will show the prognostic significance of the ECG changes.

In 70 patients (3 females and 67 males), aged 16-72 years (mean: 51 +/- 9 years), the low noise ECG was recorded from body surface by the signal averaging and the high resolution beat-to-beat techniques. We found 61 patients were suffering from coronary heart disease, 4 had atypical coronary heart disease (syndrome X), 4 had dilatative cardiomyopathy, and one had the long QT syndrome (Romano-Ward syndrome). We found the following recovery rates for ventricular late potentials within the ST segment with the averaging technique: clearcut in 13/53 patients, doubtful in 16/53 patients, and late potentials absent in 26/53 patients. With the beat-to-beat technique the following recovery rates were found: clearcut late potentials in 27/70 patients, doubtful in 23/70 patients, none in 20/70 patients, and intermittently occurring late potentials in 18/70 patients (categorized as doubtful late potentials). When comparing the detection of late potentials with both methods in individual patients, we found concordant results in 39/53 patients studied (positive with both methods in 24/53 patients, negative with both methods in 15/53 patients), and discordant results in 14/53 patients (positive with the beat-to-beat technique and negative with the averaging technique in 12 individuals, negative with the beat-to-beat technique and positive with the averaging technique in the remaining 2 patients). The correlation between the incidence of late potentials and the presence of exercise-induced myocardial ischemia (submaximal bicycle exercise) was higher when using the high resolution beat-to-beat technique, as holds also true for the correlation to complex ventricular arrhythmias.(ABSTRACT TRUNCATED AT 250 WORDS)