• Several databases of ECG recordings are generally available for evaluating ECG analyzers. They serve several important needs:
• They contain representative signals. Wide variations in ECG characteristics among subjects severely limit the value of synthesized waveforms for testing purposes. Realistic tests of ECG analyzers require large sets of “real-world” signals.
• They contain rarely observed but clinically significant signals. Although it is not particularly difficult to obtain recordings of common ECG abnormalities, often those that are most significant are rarely recorded. Both developers and evaluators of ECG analyzers need examples of such recordings. They contain standard signals. System comparisons are meaningless unless performance is measured using the same test data in each case, since performance is so strongly data-dependent.
• They contain annotated signals. Typically, each QRS complex has been manually annotated by two or more cardiologists working independently. The reference annotations produced as a result serve as a “gold standard” against which a device’s analysis can be compared quantitatively.
• They contain digitized, computer-readable signals. It is therefore possible to perform a fully automated, strictly reproducible test in the digital domain if desired, allowing one to establish with certainty the effects of algorithm modifications on performance.

Specification of CTG Machine :