Coronary effects of adenosine in conscious man.

Adenosine has been reported to play an important role in several cardiac functions, including the regulation of total and regional myocardial perfusion. This hypothesis is based on extensive investigations in animal models, but very limited information is available on the cardiovascular actions of adenosine in conscious man and the effects of the intracoronary administration of adenosine are unknown. The purpose of this study was to measure total and regional coronary blood flow after bolus injections of 0.1, 0.5, 1.0, and 2.5 mg of adenosine into the left anterior descending coronary branch. A three-thermistor thermodilution catheter was advanced into the coronary sinus to measure simultaneously the great cardiac vein flow and the coronary sinus flow. Six patients with normal coronary angiograms and normal ventricular function completed the study. Intracoronary injections of adenosine were free from significant adverse effect and caused a dose-related increase of great cardiac vein flow. A linear relation was found between flow increment and the log of adenosine dose (y = 18.929x + 74.84, r2 = 0.951). The highest flow, measured after the maximal dose, was almost three times greater than control flow (155 +/- 2 vs 58 +/- 3 ml min-1, P less than 0.001). We also observed a flow response in the territory not directly exposed to adenosine, as indicated by a marked increase of coronary sinus blood flow that was linearly related to the adenosine dose (y = 29.113x = 112.635, r2 = 0.98). These preliminary observations suggest: (1) Intracoronary injections of adenosine in conscious man can be performed without significant adverse effects.(ABSTRACT TRUNCATED AT 250 WORDS)