Psychophysiological Investigations of Myocardial Ischemi (PIMI): Initial Results on Mechanisms of Cardiac Ischemia

Psychological factors are linked to outcomes in coronary artery disease (CAD) pts but the mechanisms are obscure. The PIMI is NIH multicenter study designed to test the overall hypothesis that manifestations and expressions of ischemi are influenced by specific psycho-physiologic mechanisms. Accordingly, 200 pts, mean age 62, with CAD and ischemi responses on treadmill were studied. Ambulatory ECG (AECG) monitoring, psychological instrument batteries and plasm biochemical tests were applied to identify mechanisms associated with ischemi during daily life, exercise and mental stress without influence of cardiac medications. Daily life ischemi (AECG) occurred in 41% of pts (95% with ischemi were asymptomatic) and was associated with lower hostility (p < 0.01) and anger expression (p < 0.03) scores compared with those without daily life ischemia. An inverse association between magnitude of daily life ischemi and these scores was observed. No differences were found for depression (Beck) or anxiety scores. On treadmill all pts had ischemi (ST segment depression) but 44% had angina. Angin expression was associated with higher depression (p = 0.002), anxiety (State, P = 0.002 and Trait, P = 0.01) and autonomic perception (p = 0.05) scores than no angina. Depression best predicted time to angin (Cox model, P = 0.007). During mental stress (Stroop and speech tasks) ischemi (radionuclide ventriculogram (RVG) or ST segment abnormalities) occurred in 79% of pts (95% with ischemi were asymptomatic) and associated with higher Reward, Dependence, (Temperament and Character Inventory, p < 0.02) and level of irritation during Stroop task (p < 0.01). Plasm norepinephrine remained low, but epinephrine doubled and systolic pressure increased. No associations were found for medical or demographic factors examined. During bicycle exercise ischemi (RVG abnormality) occurred in 94% of pts (64% with ischemi were asumptomatic) yet norepinephrine increased three-fold. In summary, daily life ischemi (usually asymptomatic) is associated with suppressed hostility, anger and emotion but not depression or anxiety. mental stress ischemi (mostly asymptomatic and with epinephrine release) is related to temperament characteristics. Exercise stress ischemia, on the other hand, more often evokes symptoms and marked norepinephrine release but symptom expression seems dependent upon depression, anxiety and autonomic perception. Mechanisms responsible for ischemi evoked in different settings and its symptomatic expression involve complex interactions of behavioral, physiological and psychophysiological factors.