Reproducibility and variation in assessing late potentials

As with any test, the diagnostic validity of late potentials identified by the signal averaged electrocardiogram (ECG) depends on the reproducibility of the data. In turn, the assessment of treatment effects requires definition of variations intrinsic to the measurements made. Technical aspects of recording and analyzing late potentials cause inconsistencies that compound the expected biological variation. The problem is further confounded by sometimes disparate definitions, recording techniques and algorithms for analysis used by different laboratories and devices, nuances that can determine diagnostic categorization. We will try to identify those factors critical to making studies in different laboratories equivalent.