Responses of the QT interval of the electrocardiogram during emotional stress.

The relationship of emotional stress to the duration of the QT interval of the electrocardiogram (which contains the period of repolarization of the myocardium) was explored because QT prolongation has been shown under some circumstances to carry a risk of potentially fatal cardiac arrhythmia. A thoroughly studied case of repeated serious and ultimately fatal arrhythmia which occurred in a setting of overwhelming family and personal stress and which was preceded by marked prolongation of the QT interval prompted an experimental study of the behavior of the QT interval during stressful interviews. The subjects were 17 men and women ranging in age from 26 to 74. The experimental sessions included: 1) a period of inactivity with the subject sitting alone, 2) a period of "neutral" discussion, 3) a period of dwelling on a presumed stressful topic, followed by 4) a period of reassurance. Heart rate, respiration, arterial pressure, and the electrocardiogram were recorded throughout the four intervals together with a real time tracing of the QT interval of the electrocardiogram made by a computerized instrument recently devised by one of us (J.E.). Most of the subjects reacted to the stressful discussion with anger and resentment that was associated with shortening of QT. Two of them, however, who reacted with dejection and a feeling of being overwhelmed, displayed lengthening of QT. The QT changes were generally not linked to changes in heart rate.