Effects of acute alcohol infusion on duration and dispersion of QT interval in male patients with coronary artery disease and in healthy controls

Background and hypothesis: Alcohol consumption may have advantageous epidemiologic effects but ethanol also increases the risk of sudden coronary death. Prolongation of QT interval has been reported in chronic alcoholics. Long QT period predisposes to serious arrhythmias, and therefore we studied whether acute alcohol intoxication prolongs repolarization in patients with stable coronary artery disease (CAD). Methods: The effects of acute ethanol steady-state intravenous infusion (0.72 g/kg body weight within 60 min) on QT interval and QT dispersion, assessed by 12-lead electrocardiograms (ECG), were studied in 22 men with stable CAD and in 10 controls. Heart rate variability was measured by Holter recordings. Results: Mean blood alcohol rose to 26.1 +/- 4.3 mmol/l (1.2 +/- 0.2 parts per thousand), and was maintained for 2 h. Heart rate was 56 +/- 7 beats/min before and 54 +/- 8 beats/min during ethanol infusion (NS). The heart rate-adjusted QT interval increased on the average 13-23 ms over the 12-lead ECG (p < 0.005). The QT dispersion remained unaltered. The was no difference in the repolarization response in the patients with CAD compared with the controls. The high- and low-frequency components of heart rate variability remained unaltered. Conclusions: In middle aged men, regardless of the presence of CAD, moderate amounts of alcohol cause prolongation of ventricular repolarization. Changes in the activity of the autonomic nervous system do not seem to explain the observed phenomenon.