Dispersion of the corrected QT and JT interval in the electrocardiogram of alcoholic patients.
BACKGROUND
The aim of this study was to analyze the corrected QT interval (QTc), its dispersion (QTcd), and the QT interval index (QTcI) and to compare it with the corrected JT interval (JTc), its dispersion (JTcd), and the JT interval index (JTcI) in long-term alcoholic users, by investigating the ventricular activation until the completion of repolarization.


METHODS
The study of ECGs was performed on a selected group of 49 male white alcoholic patients, mean age 53.51+/-4.78 years. The control group was pair-matched. The analysis of ECGs was performed according to the Minnesota Code, and Bazett's formula gave the values of the corrected QT interval and JT interval.


RESULTS
The results of the descriptive statistics in the group of alcoholics showed a range of the QTcd of 12.0 to 103.0 milliseconds, mean 44.2+/-18.6 milliseconds, compared with 5.0 to 68.0 milliseconds, mean 23.8+/-11.1 milliseconds, in the control group (p < 0.0001). The range of JTcd in the alcoholic patients was 11.0 to 88.0 milliseconds, mean 43.0+/-18.3 milliseconds, compared with 5.0 to 66.0 milliseconds, mean 22.8+/-12.1 milliseconds, in the control group (p < 0.0001). The QTc from 422.0 to 480.0 milliseconds was obtained in 69.4% of the alcoholic patients and 32.6% of the controls. The QTc over 480.0 milliseconds was found in 24.5% of the alcoholic patients, but was not recorded among the controls at all (p < 0.0001). The QTcd over 50.0 milliseconds was registered in 34.7% of the alcoholic patients, while in the controls a QTcd above 50 milliseconds was found in 2.0% (p < 0.0001). The mean values of QT were markedly higher in the alcoholic patients (p < 0.01) than in the controls. The same was the case with the values of QTd, QT(I), QTcd, and QTcI (p < 0.0001). Also, the mean values of JTd, JT(I), JTc, JTcd, and JTcI were significantly higher in the alcoholic patients than in the controls (p < 0.0001). The mean value of JT, although higher in the alcoholic patients, did not significantly differ between the examined groups (p=0.1002). The odds ratio estimated for prolonged QTc and for enlarged QTcd in the alcoholics versus the controls was 31.625 and 25.500 (p < 0.0001), respectively.


CONCLUSIONS
Persons who consume various alcoholic beverages excessively and for a long time have significantly higher dispersions of the QTc and JTc, intervals and they have a significantly higher estimation of relative risk for the prolonged QTc interval and higher QTc dispersion than the control group, i.e., higher risk of arrhythmias.
Corović
Naima
N
Institute for Medical Research and Occupational Health, Zagreb, Croatia. ncorvic@imi.hr
Duraković
Zijad
Z
Misigoj-Duraković
Marjeta
M
D000437:Alcoholism / Q000175:diagnosis / Q000503:physiopathology; D002310:Cardiomyopathy, Alcoholic / Q000175:diagnosis* / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted