The measurement of beat-to-beat
QT interval variability (QTV) shows clinical promise for identifying several types of
cardiac pathology. However, until now, there has been no device capable of displaying, in real time on a beat-to-beat basis, changes in QTV in all 12 conventional leads in a continuously monitored patient. While several
software programs have been designed to analyze QTV, heretofore, such programs have all involved only a few channels (at most) and / or have required laborious user interaction or off-line calculations and post-
processing, limiting their clinical utility. This invention discloses a PC-based ECG
software program that in real time, acquires, analyzes and displays QTV and PQ interval variability (PQV) in each of the
independent channels that constitute the 12-lead conventional and / or Frank X, Y, Z lead ECG. The
system also analyzes and displays the QTV and PQV from QT and PQ interval signals that are derived from multiple channels and from
singular value decomposition such that the effect of
noise and other artifacts on the QTV and PQV results are substantially reduced compared to existing single-channel methods. Moreover, this invention also discloses certain new parameters of T-wave (and QRS and P-wave) morphology, that in initial studies have improved clinical diagnostic utility and / or reproducibility and reliability compared to known existing parameters of T-wave morphology. Finally, it also discloses a method for determining the beat-to-beat variability these T, QRS and P-wave morphologic parameters.