PERFORMANCE OF AN ELECTROCARDIOGRAPHIC ANALYSIS SYSTEM - IMPLICATIONSFOR PHARMACODYNAMIC STUDIES

The performance of a digital data-acquisition and -analysis system in measuring cardiac complex intervals was compared with manual measureme nts in 10 healthy subjects. A data set of 500 cardiac complexes was cr eated from lead II electro cardiographic samples from each subject. In tervals were measured to the nearest 5 msec by hand and to the nearest 1 msec by the analysis system. Automated measurements of the RR inter val and QRS duration exhibited no bias and median absolute errors of 3 msec. Measurements of the PR interval exhibited a significant bias (1 8 msec) that accounted for the majority of the imprecision (19 msec). A small but significant bias (4 msec) was found in the measurement of the QT duration with a median absolute error of 12 msec. The tradition al method of averaging the values of 10 consecutive complexes provided results similar to individual complex measurements. The automated ana lysis of cardiac intervals can produce data that are suitable for phar macodynamic studies.