Effect of beta-blockade on low heart rate-related ischemia during mental stress

Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California 90048.

To explore the effect of beta-adrenergic blockade on low heart rate-related (mental stress) ischemia, 19 patients with coronary artery disease were randomized into a double-blind crossover trial of metoprolol, 100 mg twice daily, and underwent serial mental stress/bicycle exercise studies. Mental stress-induced wall motion abnormalities occurred at a lower heart rate than exercise-induced wall motion abnormalities during placebo administration (81 +/- 16 vs. 123 +/- 20 beats/min, p less than 0.05). Metoprolol reduced the mean magnitude of exercise-induced wall motion abnormalities (2.8 +/- 2.0 vs. 1.6 +/- 2.4, p = 0.003); improvement was related to the magnitude of hemodynamic beta-blockade effect. Metoprolol did not significantly reduce the mean magnitude of mental stress-induced wall motion abnormalities (3.0 +/- 2.2 vs. 2.6 +/- 2.2), although individual responses predominantly either improved (50%) or worsened (29%). Unlike exercise, the magnitude of hemodynamic beta-blockade did not predict mental stress response and metoprolol did not block mental stress-induced blood pressure elevations. Patients with abolition of exercise-induced ischemia were more likely to have reduction of mental stress-induced ischemia. Patients whose ischemia worsened with metoprolol during mental stress had more easily inducible ischemia, as assessed by exercise-induced placebo wall motion abnormality, chest pain and prior myocardial infarction. Beta-blockade was associated with a lowering of ischemia-related hemodynamic thresholds compared with placebo. These results suggest that beta-blockade has a variable effect on low heart rate-related ischemia that may be due to a lack of effect on mental stress-induced blood pressure elevation in patients with easily induced ischemia or to effects on coronary vasomotor tone, or both.

This article has been cited by other articles:

				P.C Strike and A Steptoe Systematic review of mental stress-induced myocardial ischaemia Eur. Heart J., April 2, 2003; 24(8): 690 - 703. [Full Text] [PDF]

				P.R James, P Taggart, S.T McNally, S.P Newman, S.C Sporton, and S.M.C Hardman Acute psychological stress and the propensity to ventricular arrhythmias. Evidence for a linking mechanism Eur. Heart J., June 2, 2000; 21(12): 1023 - 1028. [Abstract] [PDF]

				T. C. Andrews, J. D. Parker, S. Jacobs, R. Friedman, N. Cummings, G. MacCallum, F. Mannting, G. H. Tofler, W. Carlson, J. E. Muller, et al. Effects of therapy with nifedipine GITS or atenolol on mental stress-induced ischemic left ventricular dysfunction J. Am. Coll. Cardiol., November 15, 1998; 32(6): 1680 - 1686. [Abstract] [Full Text] [PDF]

				E. C. D. Gullette, J. A. Blumenthal, M. Babyak, W. Jiang, R. A. Waugh, D. J. Frid, C. M. O'Connor, J. J. Morris, and D. S. Krantz Effects of Mental Stress on Myocardial Ischemia During Daily Life JAMA, May 21, 1997; 277(19): 1521 - 1526. [Abstract] [PDF]

				A. D. Goldberg, L. C. Becker, R. Bonsall, J. D. Cohen, M. W. Ketterer, P. G. Kaufman, D. S. Krantz, K. C. Light, R. P. McMahon, T. Noreuil, et al. Ischemic, Hemodynamic, and Neurohormonal Responses to Mental and Exercise Stress: Experience From the Psychophysiological Investigations of Myocardial Ischemia Study (PIMI) Circulation, November 15, 1996; 94(10): 2402 - 2409. [Abstract] [Full Text]