Acute alcohol intake and QT dispersion in healthy subjects.

OBJECTIVE: QT dispersion (QTd) is the maximal interlead difference in the QT interval on the surface 12-lead electrocardiogram (ECG). An increase in QTd is found in patients with various cardiac diseases and reflects cardiac autonomic imbalance. Variability of QT duration among the 12 surface ECG leads expresses electrical instability and greater susceptibility to malignant ventricular arrhythmias. Electrophysiological studies have shown that heavy episodic drinking facilitates the induction of ventricular tachyarrhythmias in some heavy drinkers. However, the association between QTd and acute alcohol intake has not been studied previously in healthy subjects.

METHOD: In a randomized crossover study, 10 healthy male volunteers (average [SD] age 30 [2.1] years, range: 25-33) received either alcohol (six 12-oz cans of beer) or placebo (juice). The alcohol group consumed 0.97 [0.12] g/kg body weight ethanol, and the placebo group consumed the same amount of juice in a 1-hour period. After a 48-hour washout period, the alcohol group drank juice, and the juice group drank alcohol. QTd and corrected QTd (cQTd) were measured in a baseline ECG after the alcohol period (AP) and after the juice period (JP).

RESULTS: In comparison with baseline ECG (31.7 [9.4] ms), QTd values after AP (42.1 [10.8] ms) were significantly prolonged (p = .027), but this was not so after JP (33.8 [7.1] ms; p = NS). Also in comparison with baseline ECG (35.7 [11.1] ms), cQTd values after the AP (49.8 [12.7] ms) were significantly prolonged (p = .005), but again, this was not so after the JP (36.8 [7.3] ms; p = NS).

CONCLUSIONS: Heavy episodic drinking is associated with an increase in QTd and cQTd.