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ECG measurements in end QRS notching and slurring

2013; Elsevier BV; Volume: 46; Issue: 5 Linguagem: Inglês

10.1016/j.jelectrocard.2013.06.011

1532-8430

Peter W. Macfarlane, Elaine Clark,

ECG Monitoring and Analysis

There has been a significant interest in recent times in the detection of end QRS slurring and notching, at least from a visual point of view. This is linked with a resurgence of interest in an ECG pattern identified some time ago and subsequently called early repolarization which in turn, has more recently been associated with life threatening cardiac arrhythmias. The definition of early repolarization in recent papers refers to the presence of end QRS slurring or notching in an imprecise way. On the other hand, as far as is known, there are no recommendations on the definition of end QRS notching and slurring that could easily be applied to automated ECG interpretation. This is of considerable importance given the millions of ECGs reported annually worldwide using computer assisted techniques. A number of manufacturers have ECG interpretative software which includes a statement on early repolarization but in all probability, such an interpretation is more likely to be based on the presence of ST elevation than on the occurrence of QRS notching or slurring. The seminal paper on ECG wave measurement was prepared by the working party of the European Project entitled Common Standards in Quantitative Electrocardiography (CSE). That paper gave many examples of QRS termination or offset but did not specify in detail rules for measurement of slurs or notches. The paper stated that “a deflection is slurred when it displays a distinctive change in slope”. It also said that “a notch is an abrupt change in the direction of a limb of a wave or deflection. A notch has at least 2 turning points located on the same side of the reference level regardless of their distance, amplitude or duration”. These definitions lack precision opening the door for software developers to interpret them in whatever way they wish.