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Biomedical subjects

U Teppner

Publications and source records attributed to U Teppner.

2 recordsLinked to original sources

A technique to evaluate the performance of computerized ECG analysis systems.

No objective method to test computerized ECG systems has been available. Until now, tests have been conducted separately for instrumentation and algorithms. Hence, to facilitate objective verification and testing of modern computerized ECG equipment, a dedicated high resolution, low noise instrument (an "electronic test patient") has been developed. The purpose of this communication is to describe this new instrument and its electrocardiographic database. The instrument is designed not to cause any disturbances to the original ECG signals in the frequency range from 0 to 1 kHz. The input channels accommodating standard 12-lead and 3-lead Frank systems are sampled simultaneously at 10 kHz each with 90 dB dynamic range. The overall RMS noise figure of the instrument is 1 microV. The integral part of the instrument is a high resolution, high bandwidth minidatabase consisting of selected A-type and B-type verified electrocardiograms such as infarctions, ventricular hypertrophies, atrial fibrillations, etc. The minidatabase was collected with the aid of a computerized ECG system, which has a program for searching for specific electrocardiographic diagnosis. Each database record consists of simultaneous electrocardiographic signals of all standard leads and Frank leads, and a validated diagnostic report. A system under test is typically connected via its patient cable to the analog output of the instrument. The testing is performed with reference to the validated ECG from the database. In that way, our minidatabase is compatible with any electrocardiographic system. The only similar database assembled for testing purposes is that of the CSE group.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer Systems↗

Estimation and removal of baseline drift in the electrocardiogram.

Estimation procedures for baseline drift have been developed using cubic spline, polynomial, and rational functions. In a test set of 50 electrocardiograms (ECGs), each of 2.5-sec duration, baseline stability was significantly improved by application of any of these methods, except rational function approximation. Amplitude histograms of clinical ECGs after subtraction of estimated baseline distortions showed only small baseline variations over the recording period. For a quantitative validation of the estimation procedures, 10 ECGs with artificial baseline drift were constructed and analyzed by correlation and mean square error calculations. From these comparisons, the polynomial approximation emerged as the most efficient method.

Biometry↗