Se. Legault et al., PATHOPHYSIOLOGY AND TIME-COURSE OF SILENT-MYOCARDIAL-ISCHEMIA DURING MENTAL STRESS - CLINICAL, ANATOMICAL, AND PHYSIOLOGICAL CORRELATES, British Heart Journal, 73(3), 1995, pp. 242-249
Objective-To define the prevalence and pathophysiology of myocardial i
schaemia induced by mental stress in patients with coronary artery dis
ease and exercise inducible ischaemia, and to determine the correlatio
n between the severity of coronary artery disease and ischaemia induce
d by speech. Design-Prospective cohort study. Setting-Tertiary care ac
ademic institution. Patients and protocol-47 patients with coronary ar
tery disease and 20 normal controls were studied using standardised ex
ercise and mental stress. The ambulatory nuclear vest provided continu
ous measures of left ventricular ejection fraction and relative volume
changes: an ischaemic response to mental stress was defined as a decr
ease in ejection fraction of greater than or equal to 5% for greater t
han or equal to 60 s. Severity of coronary artery disease was assessed
by the extent of thallium reversibility on exercise testing and the s
everity of angiographic disease. Results-23 (49%) of 47 patients with
coronary artery disease had an ischaemic response to mental stress whi
ch occurred early, was sustained throughout the task and associated wi
th an increase in end systolic volume. In contrast, the pattern of lef
t ventricular response in the remaining 24 patients (51%) resembled th
at in the normal controls. Patients with mental stress induced ischaem
ia tended to have greater severity of coronary disease (mean (SD) tota
l number of diseased vessels 1.9 (0.8) v 1.4 (0.9), P = 0.07), more fr
equent exercise induced angina (17/23 v 7/24, P = 0.003) and lower inc
reases in heart rate (36 (11) v 49 (23) beats per min, P = 0.023) and
systolic blood pressure (32 (19) v 45 (18) mm Hg, P = 0.03) during exe
rcise. Left ventricular responses to speech and exercise were Canada c
ompared in the 23 patients with mental stress induced ischaemia: menta
l stress was associated with a greater decrease in ejection fraction a
t comparable increases in rate pressure product (- 6.5 (6.3)% v 4.7 (1
1.2)%, P = 0.0001). Conclusions-These findings suggest that mental str
ess induction of myocardial ischaemia is common in patients with stabl
e coronary artery disease. Susceptible patients may have more function
ally severe coronary disease. The time course, pattern, and haemodynam
ic features of mental stress induced ischaemia suggest a dynamic decre
ase in coronary supply.