New sex dependent normal limits of the signal averaged electrocardiogram.

Abstract

Background-An earlier study of 1555 normal 12 lead electrocardiograms has shown that the mean QRS duration in men is 8 ms longer than in women. Objective-To establish the sex related normal limits of the signal averaged electrocardiogram. Results-There were significant differences between the two sexes in QRS duration (mean (95% confidence interval (95% CI)) (8.0 (3.1 to 13*0) ms, t = 3-29, degrees of freedom = 41, p = 0-0021 with the 25-250Hz filter; mean (95% CI) 10-2 (6-9 to 13.5) ms, t = 6*26, degrees of freedom = 53, p < 0-0001 with the 40-250Hz filter)) and in body surface area (mean (95% CI) 0*26 (0.21 to 0-31) in2, t = 10.63, degrees of freedom = 57). There was no significant correlation between age and QRS duration, LAS40, or RMS40, but there was a highly significant correlation between body surface area and QRS duration (correlation coefficient = 0-396, p < 0.0005) and RMS40 (correlation coefficient = -0-159, p < 0-025). Current sex independent criteria defining ventricular late potentials as the presence of any two of QRS duration >114 ms, LAS40 >38 ms, RMS40 <20 pV, give a specificity of 85% for men and 91% for women in this normal population.Recommendations-Ventricular late potentials should be regarded as present when (a) QRS duration exceeds 114 ms in men or 104 ms in women and (b) either LAS40 >38 ms or RMS40 <20 ,uV. This gives a specificity of 97% in men and 100% in women in the population studied. (Br Heart Y 1994;72: 197-200) The presence of ventricular late potentials has been associated with an arrhythmogenic substrate characterised by fragmented electrical activity due to delayed ventricular activation and slowed propagation of conduction in the myocardium, which in turn seems to be related to the development of ventricular arrhythmias.' The signal averaged electrocardiogram has been used to detect ventricular late potentials in order to select patients at risk of future arrhythmic events on account of their underlying clinical problem-for example, recent myocardial infarction,2 hypertrophic cardiomyopathy,3 etc. The incidence of ventricular late potentials is reported to be from 0-7% in normal people without sustained ventricular tachycardia,4--that is, present criteria have a specificity of 93%-100%. Late potentials occur in 20% of patients with structurally normal hearts and sustained ventricular tachycardia.5 A European and North American task force recently suggested guidelines for defining the presence of ventricular late potentials,6 but these were not sex dependent.Our previous studies of the normal 12 lead electrocardiograms of 1330 healthy people,7 recently extended to 1555 healthy volunteers, have shown that the mean QRS duration in men is 8 ms longer than in women (table 1). Therefore it was thought necessary to establish sex related normal limits of the signal averaged electrocardiogram. Methods 195 people (160 men and 35 women, aged 40 to 69, table 2) with normal clinical history, physical examination, 12 lead electrocardiogram, and echocardiogram were recruited ...

Age and Sex Differences in the P-Wave Signal-Averaged Electrocardiogram in a Japanese Study Population.

“…Raineri, et al 5) reported that the difference between the sexes could be corrected by adjusting for height. Yang, et al 7) reported a strong correlation between fQRS and body surface area. Ozawa, et al 11) reported a difference fQRS values between the sexes and a correlation between fQRS values and body surface area in a Japanese cohort of SAE.…”

“…Previous reports suggest that the diagnostic criteria between normal and abnormal SAE values and the late potentials of QRS vary, depending on the equipment used and how the filters are set. However, according to these reports, values determined from a 95% confidence interval of normal subjects [3][4][5][6][7] or determined standard values for comparison of myocardial infarction patients with and without ventricular tachycardia [8][9][10] those criteria varied. The difference in RMS 20 caused by (F) and (B) filter direction was also observed in our study.…”

“…Evaluation with a natural logarithm has been omitted from this report for this reason. Danford, et al 3) and Yang, et al 7) reported a significant difference between the sexes in QRS waves SAE and proposed setting standard values for each sex. Raineri, et al 5) reported that the difference between the sexes could be corrected by adjusting for height.…”

Evaluation of the Normal Values for Signal‐Averaged Electrocardiogram

“…Yang and MacFarlane 7 found no specific age‐related change in normals between the ages of 40 and 69 years in any of the three SAECG parameters. Mercando et al compared SAECG data in 51 normal subjects, aged 62–102 years, with 25 asymptomatic volunteers under the age of 50 13 .…”

“…However, it was not noted that the filtered fQRS duration may be different by gender. Over the past decade, there has been no modification of these normal values despite several published studies that indicate that there are gender‐related differences in the SAECG 3–8 …”