J. Vojacek et al., CHANGES IN PROXIMAL AND DISTAL CORONARY-ARTERY DIAMETER DURING ATRIALPACING-INDUCED MYOCARDIAL-ISCHEMIA, Coronary artery disease, 6(9), 1995, pp. 685-691
Background: The present study was designed to evaluate the role of tac
hycardia-induced dynamic coronary artery diameter changes in the devel
opment of myocardial ischemia. Methods: Coronary angiography at rest a
nd during atrial pacing-induced myocardial ischemia was performed in 2
2 patients. The diameter of the proximal and the corresponding distal
coronary artery segments at rest and during pacing was measured using
quantitative coronary angiography. Plasma levels of noradrenaline, adr
enaline, dopamine and endothelin were determined in a subset of 14 pat
ients in blood drawn from aorta and coronary sinus at rest and during
pacing. Results: Luminal diameter in normal proximal and distal segmen
ts increased, respectively, from 2.93+/-0.34 and 1.40+/-0.04 mm at res
t to 3.0+/-0.25 and 1.58+/-0.07 mm during atrial pacing. The diameter
of the proximal coronary artery segments with significant concentric s
tenosis decreased from 1.28+/-0.4 mm at rest to 0.95+/-0.34 mm during
pacing, whereas segments with either significant eccentric or non-sign
ificant stenosis did not change significantly. A correlation was found
between the noradrenaline level in the coronary sinus and the distal
coronary artery diameter. Conclusions: A decrease in diameter of coron
ary artery segments with concentric stenosis during tachycardia might
contribute to the development of myocardial ischemia. Some of the dyna
mic coronary artery changes may be influenced by the plasma level of n
oradrenaline. No evidence was found to suggest that dynamic changes in
the diameter of proximal segments are related to the changes in diame
ter of the corresponding distal segments.