Psychophysiological Investigation of Myocardial Ischemia (PIMI)

Objectives:

To invesitigate psychophysiological factors related to both symptomatic and asymptomatic cardiac ischemia.

Background:

An important hypothesis has been generated from current research in this area: manifestations and expressons of cardiac ischemia are influenced by specified psychophysiological mechanisms.

Subjects:

The study population consisted of 196 patients recruited from four clinical units all of which were clinical units for the Asymptomatic Cardiac Ischemia Pilot (ACIP). Patients eligible for PIMI were identified throughout the screening process established for the enrollment patients in ACIP.

Design:

The primary goal of PIMI was to test the hypothesis, "Manifestations and expressions of cardiac ischemia are influenced by specific psychophysiological mechanisms." The specific relationship to be investigated were:

1. Patients who are susceptible to mental stress ischemia (indexed by new left ventricular wall motion abnormalities) would display more ischemia during daily activities and would have ambulatory ischemia at lower heart rate and activity level thresholds than patients who are not susceptible.
2. Cardiovascular and catecholamine reactivity to mental stress would be a predictive of severity of mental stress ischemia and of ambulatory ischemia.
3. B-edorphin responses to mental stress and to exercise would be predictive of asymptomatic ischemia.
4. Patients with systematic ischemia and those with asymptomatic ischemia would show differences in each of the following at rest and after response to stresses (Exercise and/or mental tests).
5. Mental stress would produce different hormonal and perceptual responses than exercise.
6. Asymptomatic Ischemia would be associated with a lesser severity of ischemia than symptomatic ischemia.
7. The location of the ischemic myocardium would be inferior in a higher proportion of patients with asymptomatic ischemia than of patients with symptomatic ischemia.
8. The latency internal that would be the onset of ST segment depression and the onset of ischemic pain would be related to somatic sensory perception, autonomic nervous system reflux control of the heart, B-endorphin responses, and psychosocial characteristics.