TY - JOUR
T1 - Impaired coronary vasodilator responsiveness as a cause of lactate production during pacing-induced ischemia in patients with angina pectoris and normal coronary arteries
AU - Greenberg, Mark A.
AU - Grose, Richard M.
AU - Neuburger, Naftoli
AU - Silverman, Rubin
AU - Strain, Janet E.
AU - Cohen, Michael V.
PY - 1987
Y1 - 1987
N2 - Subgroups of patients with angina pectoris and normal coronary arteries are known to have pacing-induced lactate production and, therefore, myocardial ischemia. To examine the mechanism of this pacing-induced ischemia, the effect of incremental atrial pacing on coronary blood flow and metabolism was studied in 27 patients with angina and normal coronary arteries. Seventeen patients continued to exhibit normal lactate extraction even at heart rates up to 160 beats/min (Group 1), whereas in 10 patients (Group 2) lactate extraction changed to production at the highest pacing rate. Coronary blood flow increased in Group 1 patients by 18, 41 and 75%, respectively, as heart rate was increased by 20 beat/min increments from 100 to 160 beats/min. In contrast, coronary blood flow increased by only 8, 7 and 14%, at the three respective pacing rates in Group 2. Between the heart rates of 100 and 160 beats/min, coronary vascular resistance decreased 32% in Group 1 patients but was unchanged in Group 2 patients. There was no significant change in the ratio of myocardial 02 consumption/rate-pressure product in Group 1 patients, but this ratio decreased from 0.91 ± 0.26 ml O2·min−1·(mm Hg·beats/min)−1 to 0.53 ± 0.11 (p < 0.05) in Group 2 patients as heart rate increased from baseline to 160 beats/min. Thus, patients with angina and normal coronary arteries who develop ischemia with pacing have a decreased coronary vasodilator response that interferes with their ability to increase myocardial oxygen supply to match the higher demand.
AB - Subgroups of patients with angina pectoris and normal coronary arteries are known to have pacing-induced lactate production and, therefore, myocardial ischemia. To examine the mechanism of this pacing-induced ischemia, the effect of incremental atrial pacing on coronary blood flow and metabolism was studied in 27 patients with angina and normal coronary arteries. Seventeen patients continued to exhibit normal lactate extraction even at heart rates up to 160 beats/min (Group 1), whereas in 10 patients (Group 2) lactate extraction changed to production at the highest pacing rate. Coronary blood flow increased in Group 1 patients by 18, 41 and 75%, respectively, as heart rate was increased by 20 beat/min increments from 100 to 160 beats/min. In contrast, coronary blood flow increased by only 8, 7 and 14%, at the three respective pacing rates in Group 2. Between the heart rates of 100 and 160 beats/min, coronary vascular resistance decreased 32% in Group 1 patients but was unchanged in Group 2 patients. There was no significant change in the ratio of myocardial 02 consumption/rate-pressure product in Group 1 patients, but this ratio decreased from 0.91 ± 0.26 ml O2·min−1·(mm Hg·beats/min)−1 to 0.53 ± 0.11 (p < 0.05) in Group 2 patients as heart rate increased from baseline to 160 beats/min. Thus, patients with angina and normal coronary arteries who develop ischemia with pacing have a decreased coronary vasodilator response that interferes with their ability to increase myocardial oxygen supply to match the higher demand.
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U2 - 10.1016/S0735-1097(87)80227-9
DO - 10.1016/S0735-1097(87)80227-9
M3 - Article
C2 - 3558975
AN - SCOPUS:0023125519
SN - 0735-1097
VL - 9
SP - 743
EP - 751
JO - Journal of the American College of Cardiology
JF - Journal of the American College of Cardiology
IS - 4
ER -