thesis
Intra-individual Variability of the Electrocardiogram: Assessment and exploitation in computerized ECG analysis
- Publication date
- 20 September 2000
- Publisher
- Computer interpretation of the electrocardiogram (ECG) was one of the first applications
of computers in health care. The first systems were developed in the
early sixties by Pipberger and Caceres. In the last decades, computerized
ECG analysis has become one of the most widespread computer applications
for decision support in health care. For example, over 50 million ECGs were
analyzed by computer in the United States already in 1988.
Large research efforts have been made to bring the performance of these systems
to a level acceptable for routine use. In an international cooperative study,
called 'Common Standards for Quantitative Electrocardiography' (CSE), most
present-day ECG computer programs were evaluated. This evaluation was
done by comparing measurements and interpretations computed by these systems
with those of a panel of experienced cardiologists on the one hand, and
with a diagnosis based on clinical evidence, not involving the EeG, on the other.
It was concluded that ECG analysis programs can assist clinicians in achieving
lllore unifornl and consistent interpretations of ECGs. However, continued testing
and refinenlent was deelned necessary to enhance the perfonnance of these
systenls.
Despite their good diagnostic performance, ECG analysis programs suffer from
a number of drawbacks that limit their practical utility.
One of the most important shortcomings is the vulnerability for individual ECG
variability. Identical ECG signals will result in identical measurements
and interpretations, but small (and diagnostic inconsequential) differences between
signals may result in an entirely different diagnostic interpretation.
This variability can already be a problem when, e.g., multiple ECGs of the same
patient are interpreted that have been recorded only minutes apart. Instable interpretations
will not only considerably diminish the practical use of ECG computer
prograrlls, users will also lose confidence in their performance. Furthernlore,
variation in interpretations of shnilar ECGs suggests that the accuracy of
programs can still be improved.