Day-to-day reproducibility of mental stress-induced abnormal left ventricular function response in patients with coronary artery disease and its relationship to autonomic activation.

BACKGROUND: Mental stress (MS) results in left ventricular (LV) dysfunction in approximately half of the patients with symptomatic coronary artery disease (CAD) and is an adverse prognostic sign. The reproducibility of various MS tasks in inducing LV dysfunction and its relationship to autonomic activation in patients with CAD are not known. We studied the reproducibility on different days of 3 commonly used MS tasks on LV ejection fraction (LVEF), heart rate, blood pressure, and rate-pressure product and the relationship of reproducibility to autonomic activation as determined by heart rate variability in patients with chronic stable angina. METHODS AND
RESULTS: Ten patients with CAD and exercise-induced ischemia who had abnormal LVEF responses to at least one MS task from a battery of MS tasks (mental arithmetic, anger recall, and color Stroop test) while undergoing continuous ambulatory Holter and LV function monitoring underwent a second MS testing 4 to 8 weeks later, with no change in clinical status or cardiac medications in the interim. Autonomic tone was determined from indexes of heart rate variability (high frequency [HF] for parasympathetic activity and low frequency [LF] and low frequency/high frequency ratio [LF/HF] for sympathetic activity). MS tasks resulted in a small increase in heart rate (P <.0001), a modest increase in systolic blood pressure (P <.0001) and the rate-pressure product (P <.0001), and a small but statistically significant increase in LF (P <.002) and LF/HF (P <.0001), but no change in HF compared with baseline. These changes were highly reproducible over the 2 studies. With a fall in LVEF of 5% or greater considered as indicative of an MS-positive task, anger recall was the most effective and reproducible MS task in inducing LV dysfunction. MS-positive tasks were associated with a greater increase in systolic blood pressure (P =.005). Anger recall resulted in a trend toward a higher increase in systolic blood pressure (P =.08) than the other MS tasks. In MS tasks with inconsistent LVEF responses in the 2 studies (LV dysfunction present in one study but not in the other), there was significant parasympathetic withdrawal (P =.02) in MS-negative tasks but no difference in sympathetic activation. On the other hand, in MS tasks with consistent LV dysfunction on both occasions, there was no difference in parasympathetic or sympathetic activation. MS-positive tasks were not accompanied by chest pain or ST depression.
CONCLUSIONS: Of the commonly used MS tasks, anger recall produces LV dysfunction with the highest frequency and is the most reproducible task when retested 4 to 8 weeks later in patients with CAD. These data are relevant for planning studies of the effects of therapeutic interventions on MS-induced LV dysfunction.