Abstract
Summary
The correlation between circulating catecholamines and ventricular vulnerability during psychologic stress was examined in conscious dogs. The repetitive extra-systole (RE) threshold was used to assess vulnerability to ventricular fibrillation. Exposure of the animals to a stressful sling environment compared to that of nonstressful cage setting resulted in a significant 41% (P < 0.01) reduction in the RE threshold. Plasma levels of norepinephrine and epinephrine increased twofold (P < 0.05) and fourfold (P < 0.01), respectively. It is concluded that the elevation in circulating catecholamine levels correlates closely with enhanced ventricular vulnerability during psychologic stress and that the model for psychologic stress employed results in substantial increases in plasma catecholamine levels which is in large part due to release of epinephrine from the adrenal medulla.
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