[Changes in myocardial metabolism during atrial pacing and catecholamine stimulation in normal subjects and patients...

5 patients with angina had their threshold for angina evaluated by atrial pacing and by stimulation with catecholamine (dopamine). The authors then studied the metabolic changes induced by the two types of anginogenic load (AP and D-test) applied successively, and compared them with the post-ergometry ECG changes (lowering of the ST segment by at least 2 mm) and the findings on coronary arteriography (complete obstruction of at least 75% stenosis of a major branch vessel). The metabolic measurements were controlled against those of 5 normal subjects after standard ergometry. In the patients with angina, the AP test led to a constantly negative value for %. L. By contrast, the values of D(a-v)c and % O2 which were reduced in the normals, as indirect evidence of an increased coronary flow, remained practically static. During the dopamine infusion, although the % L was reduced, it remained essentially positive, while the D(a-v)c and % O2 were consistantly lowered.