Se. Legault et al., MYOCARDIAL-ISCHEMIA DURING MENTAL STRESS-TESTING - IS THE MECHANISM DIFFERENT FROM EXERCISE-INDUCED ISCHEMIA, Homeostasis, 34(5-6), 1993, pp. 252-265
Responses to exercise and mental stress were compared in 20 male patie
nts with stable coronary disease and positive exercise thallium scinti
graphy. The ambulatory nuclear VEST provided repeated determinations o
f left ventricular ejection fraction, relative ventricular volumes, he
art rate and 2-lead ECG. These and repeated measurements of blood pres
sure were obtained throughout a series of mental tasks and a Bruce pro
tocol exercise test. Two mental stress tasks, Math-Stroop and a person
ally-relevant Speech, produced falls in ejection fraction of 5% in 80%
and 85% of subjects respectively. Compared to Bruce exercise, mental
stress- induced left ventricular dysfunction was accompanied by smalle
r increases in rate pressure product. In the 15 subjects with abnormal
left ventricular responses to both Math-Stroop and exercise, the magn
itude of fall in ejection fraction during Math- Stroop (123%) was comp
arable to that during stage 2 of Bruce exercise (137%) whereas increas
es in rate pressure product were 2000 +/- 2500 and 11000 +/- 4200 resp
ectively. In the 17 subjects with abnormal left ventricular responses
to both Speech and exercise, comparable falls in ejection fraction of
67% during Speech preparation and 56% during stage 1 exercise were ass
ociated with rate pressure product increases of 1800 +/- 1100 and 7500
+/- 2600 respectively. These features suggest a distinctive pathophys
iology for mental stress-induced left ventricular dysfunction. Assessm
ent of left ventricular response to mental stress may contribute indep
endent prognostic data in patients with stable coronary disease.