GENDER AND SIZE AND PARAMETERS OF SIGNAL- AVERAGED ELECTROCARDIOGRAPHY IN NORMAL SUBJECTS - A PRELIMINARY-STUDY

The aim of this study was to determine the influence of electrocardiog raphic and biomorphometric factors on the parameters measured by signa l averaged electrocardiogaphy (SA-ECG) in normal subjects. The study p opulation comprised 40 Caucasian students (20 men, 20 women). The SA-E CG measured 6 parameters : total duration of the averaged QRS, the roo t mean square of the voltage of the last 40 ms of the QRS (RMS 40) and the length duration of the terminal signal of under 40 mu V CLAS), ea ch parameter being measured with a band pass filter of 25 and 40 Hz. T he echocardiographic recording included measurement of 12 parameters i ncluding left ventricular mass and ventricular volumes. Five morpholog ical parameters were measured, including height, weight and body surfa ce area. The duration of QRS measured with a 25 Hz band pass filter wa s significantly longer by 9.7 ms in men than in women (102.9 +/- 8.5 m s versus 93.2 +/- 8.1 ms; p < 0.001). Similarly, QRS duration measured with the 40 Hz band pass filter was longer in men by 11.4 ms than in women (102.1 +/- 9.6 ms versus 90.7 +/- 7.5 ms; p < 0.001). Multiple l inear regression analyses showed that in both men and women, the durat ion of the QRS measured with either a 25 or 40 Hz band pass filter was correlated to size: the taller the subject, the longer the QRS durati on. A negative correlation was observed between size and RMS 40 measur ed with both 25 and 40 Hz band pass filters : the taller the subject, the smaller the value of RMS 40. None of the parameters measured by ec hocardiography were correlated to the parameters of SA-ECG. These resu lts indicate that the QRS duration measured by SA-ECG should be interp reted according to different criteria in men compared with women. This gender difference is not explained by differences in echocardiographi c parameters. The QRS duration and RMS 40 should also be interpreted w ith respect to the size of patients.