[Long-term electrocardiography: value and reliability of various systems].
25 years after the introduction of ambulatory electrocardiography four concepts are available: the conventional Holter-ECG, computer-based systems, entire ECG recording in miniaturized form and the event recorder. In contrast to visual analysis with the aid of an arrhythmia computer a more precise and quantitative evaluation of long-term ECG is possible. The reliability of a computer-based system is indicated by its sensitivity, positive predictive accuracy and reproducibility of automatic analysis. Only few of the computerized systems have been repeatedly tested on a company independent basis using these criteria in a representative number of patients, with frequent arrhythmias, and with a separate documentation of false negative, false positive and true positive events. Data available so far show that a reasonable reliability is possible, but 100% remains the exception to the rule. Thus, there is no complete automatic analysis of cardiac arrhythmias, and corrections by the physician are mandatory. This is further emphasized by the fact that only a part of all possible arrhythmias may be identified by computer whereas the other part has to be evaluated by visual control. In this context entire ECG recording is helpful, as an isolated method, however, it cannot be recommended, since the miniaturized ECG prevents analysis of subtle details and provides no quantitative data. Event recorders rely exclusively on the accuracy of the portable arrhythmia detector. Due to the concept of discontinuous ECG recording evaluation of this accuracy is pronounced problematic. Only by changing to the continuous recording mode does validation of the event recorder become possible. The first data demonstrate that the reliability of real-time analysis by the portable arrhythmia detector is not superior to highspeed analysis by the arrhythmia computer. Thus, quality control is necessary when using the event recorder as it is with continuous long-term ECG. However, there are significant limitations: with discontinuous ECG recording false negative events are not documented, separation of false positive from correct positive findings is restricted to the limited recording capacity (12-120 min real time) and the short ECG samples (6-12s) do not allow verification of sustained arrhythmias. Furthermore, questions regarding arrhythmias, ST-segment changes and pacemaker dysfunctions unidentifiable by computer remain unanswered with the use of the event recorder. For these reasons, continuous ambulatory electrocardiography providing complete data for every kind of analysis is still the standard method.(ABSTRACT TRUNCATED AT 400 WORDS)
Bethge
K P
KP
Gonska
B D
BD
D000553:Ambulatory Care; D001145:Arrhythmias, Cardiac / Q000175:diagnosis*; D005117:Cardiac Complexes, Premature / Q000175:diagnosis; D003201:Computers; D004562:Electrocardiography / Q000295:instrumentation* / Q000379:methods; D006323:Heart Arrest / Q000175:diagnosis; D006801:Humans; D008134:Long-Term Care; D013610:Tachycardia / Q000175:diagnosis; D013614:Tachycardia, Paroxysmal / Q000175:diagnosis
Langzeit-Elektrokardiographie: Wertigkeit und Zuverlässigkeit unterschiedlicher Systeme.