Effects of mental stress on left ventricular and peripheral vascular performance in patients with coronary artery disease

Objectives. We sought to investigate the mechanism of a mental stress-induced fall in left ventricular ejection fraction (LVEF) in patients with coronary artery disease. Background. Mental stress induces a fall in LVEF in a significant proportion of patients with coronary artery disease. This is accompanied by an increase in heart rate, blood pressure and rate-pressure product. Whether the mental stress-induced fall in LVEF is due to myocardial ischemia, altered loading conditions or a combination of both is not clear. Methods. Left ventricular (LV) function was studied noninvasively by serial equilibrium radionuclide angiocardiography and simultaneous measurement of peak power, a relatively afterload-independent index of LV contractility, in 21 patients with coronary artery disease (17 men, 4 women) and 9 normal subjects (6 men, 3 women) at baseline, during mental stress and during exercise. Peripheral vascular resistance (PVR), cardiac output (CO), arterial and end systolic ventricular elastance (E-a, E-es) and ventriculoarterial coupling (V/AC) were also calculated. Patients underwent two types of mental stress--mental arithmetic and anger recall--as well as symptom limited semisupine bicycle exercise. Results. Nine patients (43%) had an absolute fall in LVEF of greater than or equal to 5% (Group I) in response to at least one of the mental stressors, whereas the remaining patients did not (Group II), Group I and Group II patients were similar in terms of baseline characteristics. Both groups showed a significant but comparable increase in systolic blood pressure (15 +/- 7 vs. 9 +/- 10 mm Hg, p = 0.12) and a slight increase in heart rate (7 +/- 4 vs. 8 +/- 7 beats/min, p = 0.6) and a comparable increase in rate-pressure product (2.2 +/- 0.9 vs. 1.9 +/- 1.2 beats/min x mm Hg, p = 0.6) with mental stress. However, PVR increased in Group I and decreased in Group II (252 +/- 205 vs. -42 +/- 230 dynes . s . cm(-5), p = 0.006), and CO decreased in Group I and increased in Group II (-0.2 +/- 0.4 vs. 0.6 +/- 0.7 liters/min, p = 0.02) with mental stress, There was no difference in the change in peak power (p = 0.4) with mental stress. With exercise, an increase in systolic blood pressure, heart rate, rate-pressure product and CO and a fall in PVR were similar in both groups. Of the two mental stressors, anger recall resulted in a greater fall in LVEF and a greater increase in diastolic blood pressure. Exercise resulted in a fall in LVEF in 7 patients (33%), However, exercise-induced changes in LVEF and hemodynamic variables were not predictive of mental stress-induced changes in LVEF and hemodynamic variables. Conclusions. Abnormal PVR and E-a responses to mental stress and exercise are observed in patients with a mental stress-induced fall in LVEF. Peripheral vasoconstrictive responses to mental stress contribute significantly toward a mental stress-induced fall in LVEF. (C) 1998 by the American College of Cardiology.