Physiologic responses to epinephrine infusion: the basis for a new stress test for coronary artery disease.

Since many patients with chest pain cannot exercise adequately, an alternative stress would be useful to evaluate coronary reserve. We studied the physiologic responses to epinephrine to assess its potential. We report on 39 patients with chest pain. Doses from 0.03 to 0.30 micrograms/kg/min were administered intravenously. Heart rate increased from 72 +/- 10 to 86 +/- 12 bpm (mean +/- SD), systolic blood pressure (BP) from 122 +/- 20 to 158 +/- 18 mm Hg (increased afterload), and rate-pressure product/100 from 88 +/- 21 to 133 +/- 18. Rate-corrected pre-ejection period decreased from 141 +/- 23 to 92 +/- 14 msec and LVET/PEP ratio from 0.41 +/- 0.1 to 0.24 +/- 0.05 (increased contractility). Increased afterload and contractility increased myocardial oxygen demand. Simultaneously diastolic time and BP decreased, reducing myocardial blood supply. The endocardial viability ratio fell from 1.27 +/- 0.3 to 0.80 +/- 0.2. These data suggest that epinephrine infusion would be a useful stress test for coronary disease and are supported by a sensitivity of 87% and specificity of 100% in 23 patients with known coronary anatomy.