Background:
A decline in left ventricular (lv) ejection fraction in response to mental stress and exercise is regarded as an indicator of myocardial ischemia. in patients with lv dysfunction, the ejection fraction is sensitive to afterload, which increases during stress. thus, the effects of mental stress and exercise on lv systolic function in patients with cardiomyopathy were examined.
Methods:
The ambulatory nuclear vest (capintec, inc., ramsey, n.j.) was used to monitor lv ejection fraction in patients with cardiomyopathy (10 idiopathic and 9 ischemic). patients underwent a series of mental stress tests (serial 7s, stroop color, and paced auditory addition) and treadmill exercise. heart rate, systolic blood pressure, and lv ejection fraction were measured.
Results:
Mental stress and exercise increased heart rate and systolic blood pressure. for idiopathic cardiomyopathy, lv ejection fraction decreased during serial 7s, stroop color, paced auditory addition and exercise by -8% +/- 6%, -7% +/- 5%, -7% +/- 3%, -9% +/- 10%, respectively. for ischemic cardiomyopathy, lv ejection fraction declined by -4% +/- 3%, -7% +/- 5%, -6% +/- 3%, -2% +/- 6% during the same stress tests. there was no difference between the idiopathic and ischemic groups. each patient showed a 5% or greater decline in lv ejection fraction during one mental stress test. there was an inverse relation between changes in lv ejection fraction and systolic blood pressure during all mental stress tests and exercise (r = -0.47, p < 0.0001).
Conclusions:
In patients with depressed baseline systolic function, the decline in systolic function during mental stress and exercise could be related in part to increases in lv afterload.