DESIGN NARRATIVE:

Sophisticated electrophysiologic monitoring approaches were used to: 1) show greater sensitivity in nonhostile young men to T-wave attenuation effects of isoproterenol infusion following vagal blockade; 2) show that vagal enhancement reduced and shortened the T-wave attenuation effects of isoproterenol infusion more in hostile young men; 3) evaluate these effects of vagal blockage and enhancement in middle-aged men and in young and middle-aged women; and 4) relate the T-wave effects in these studies to other measures of vagal tone and other biobehavioral mechanisms of coronary-prone behavior.

Four studies were conducted in normal young and middle-aged men and women selected as high and low on hostility, evaluating vagal tone measures and effects of isoproterenol infusion on EKG T-wave and ST response after pretreatment with saline, neostigmine, and atropine. Demonstration that hostility was associated with deficient vagal anatagonism of SNS effects on the heart, especially in middle-aged as compared to younger persons, suggested that diminished vagal tone was one pathway whereby high hostility contributed to increased CHD risk. Clinical studies were then conducted to determine whether weaker vagal tone predicted increased myocardial ischemia and/or poorer outcomes in coronary heart disease patients.