The value of the coefficient of variation in assessing repeat variation in ECG measurements

Aims The coefficient of variation is a popular measure for describing the amount of repeat variability present in ECG measurements from recording to recording. However, it can be misleading. The aim of the present study was to assess repeat variation (reclassification) in computer measured ECG crite...

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Bibliographic Details
Published in:European heart journal 1998-02, Vol.19 (2), p.342-351
Main Authors: McLaughlin, S.C., Aitchison, T.C., Macfarlane, P.W.
Format: Article
Language:English
Subjects:
Adult
Aged
Aged, 80 and over
Biological and medical sciences
computer analysis
Diagnosis, Computer-Assisted
Electrocardiogram
Electrocardiography - methods
Electrocardiography. Vectocardiography
Electrodiagnosis. Electric activity recording
Female
Heart Diseases - physiopathology
Humans
Hypertrophy, Left Ventricular - diagnosis
Investigative techniques, diagnostic techniques (general aspects)
Male
Medical sciences
Middle Aged
repeatability
Reproducibility of Results
Citations: Items that cite this one
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Summary:Aims The coefficient of variation is a popular measure for describing the amount of repeat variability present in ECG measurements from recording to recording. However, it can be misleading. The aim of the present study was to assess repeat variation (reclassification) in computer measured ECG criteria, i.e. positive to negative or vice versa, and compare this with the coefficient of variability. Methods and Results Two ECGs were obtained from each of 295 patients, one day apart, and separately from a further 364 patients, several minutes apart. All patients were considered to be in a stable condition. Estimates of the coefficients of variation were obtained for a number of ECG parameters used in the diagnosis of left ventricular hypertrophy. Corresponding reclassification rates of relevant ECG criteria were also calculated.Large coefficients of variation were observed in voltage parameters, e.g. R in V5(20% for day-to-day recordings and 6% for minute-to-minute recordings) while the corresponding reclassification rates were 8% and 0% respectively. The repeat variation in the diagnosis of left ventricular hypertrophy was up to 5% for day-to-day recordings and up to 3% for minute-to-minute recordings based on several different criteria. Conclusion A large coefficient of variation in a particular variable does not necessarily correspond to a high reclassification rate. A better measure of the impact of ECG variability for a particular measurement is obtained from its reclassification rate. In turn, this may have a minimal effect on the overall diagnosis of a particular abnormality.
ISSN:0195-668X
1522-9645
DOI:10.1053/euhj.1997.0741