Prevalence of Spectral Turbulence and Late Potentials in a Random Population Sample

Background: Late potentials (LP) and spectral turbulence (STU) in the signal‐averaged ECG (SAECG) in patients with heart disease mark a risk of malignant ventricular arrhythmias. The prevalence and cause of STU in otherwise healthy subjects have not been established. Methods: The SAECGs of a randomly selected population sample without known heart disease, 55 men and 66 women aged 50 ± 10 years, were analyzed for LP and STU. An STU score > 1 qualified for an echocardiographic examination (echo) and a 24‐hour Holter ECG (Holter). Results: The QRS duration in lead V 2 in men was 99.5 ± 8.5 ms (mean ± SD) vs 94.2 ± 8.5 in women, P = 0.0008. The QT end was 406.7 ± 27.0 ms in women and 394 ± 24 in men, P = 0.01. The FQRSD (40 Hz) was 98.0 ± 8.6 ms in men vs 90.2 ± 9.0 in women, P = 0.0001. Subjects > 50 years of age had a lower RMS40 (33.0 ± 16.3 μV) than subjects < 50 years (40.2 ± 18.3 μV, P = 0.02). Nine (7%) subjects were LP‐positive. The STU score variables LSCR, ISCM, ISCSD and SE were positive in 12 (10%), 13 (11 %), 41 (34%) and 17 (14%) of the subjects, respectively. The mean spectral score was 0.69 ± 0.98. Eight (7%) subjects had a score of 3 or 4, considered STU‐positive. No correlation between score and gender, age or 12‐lead QRS duration was found. In score > 1, 27 (84%) had a completely normal ECHO and 31 (86%) a normal Holter. Cardiac dimensions measured by ECHO correlated with SAECG variables. Conclusions: Men had a longer mean QRS duration than women. Women had longer mean QT and JT intervals than men, which might imply an increased risk during antiarrhythmic therapy. The STU variables were not gender‐ or age‐dependent. The variable ISCSD was positive in as many as 41 (34%) presumably healthy subjects and did not seem to be a useful variable. Seven percent of the subjects were spectral turbulence‐positive and 7% were LP‐positive. A.N.E. 2000;5(1):30–38