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Figure 1 T-wave alternans magnitude increased significantly from baseline (0.04 ± 0.02 mV x ms) during induction of an angerlike behavioral state alone (to 1.40 ± 0.32, p < 0.05) and with simultaneous myocardial ischemia and angerlike response (to 3.27 ± 0.61, p < 0.05). The 3-min periods of ischemia were insufficient to increase T-wave alternans significantly from baseline (to 0.67 ± 0.09 mV x ms, p = NS). Concurrent provocation of the angerlike state and imposition of myocardial ischemia increased T-wave alternans magnitude in excess of their additive effects (p < 0.05). This amplification was blunted by beta-adrenergic blockade with metoprolol (p < 0.0004 for all), which reduced T-wave alternans at baseline (to 0.04 ± 0.01) during the angerlike state (to 0.80 ± 0.17) during myocardial ischemia (to 0.55 ± 0.11) and during simultaneous myocardial ischemia and angerlike response (to 1.23 ± 0.13). Open bars = no drug; solid bars = metoprolol. *p < 0.05.