Acute psychological stress and the propensity to ventricular arrhythmias; evidence for a linking mechanism.

Abstract

This study was designed to test the hypothesis that acute psychological stress is capable of inducing an increase in the dispersion of repolarization in patients with underlying coronary artery disease. Twenty four patients undergoing elective coronary angiography were studied, 17 with significant coronary artery disease and seven with normal coronary arteries. Following coronary angiography they were subjected to a series of timed cognitive tests, well known to induce acute psychological stress. An individual's perception of stress was assessed by visual analogue scales. Serial ECGs were recorded during the cognitive tests and QT, QRS and JT intervals measured from which QT, QRS and JT dispersion were calculated. Psychological stress was reported by the seven patients with normal coronaries and 14 of the 17 with coronary artery disease. In patients who experienced stress a marked increase in QT dispersion, reflecting JT dispersion, was observed in those with coronary artery disease (F=22.4, P=0.0001) but not in those without. At baseline there was no difference in QT dispersion between those with and without coronary artery disease (27-57 ms, 17-53 ms, P > or = 0.5). Acute psychological stress induces an increase in QT dispersion in patients with underlying coronary artery disease due to changes in JT dispersion (rather than QRS dispersion). This suggests that psychological stress modifies the dispersion of repolarization through ischaemia related changes in action potential duration.