Effects of L-arginine on flow mediated dilatation induced by atrial pacing in diseased epicardial coronary arteries.
OBJECTIVE
To examine the effects of L-arginine on basal coronary tone and flow mediated dilatation induced by atrial pacing in patients with coronary artery disease and stable angina.


METHODS
Atrial pacing was performed during intracoronary infusions of normal saline and L-arginine (150 micromol/min) in 8 patients with coronary artery disease and stable angina. The luminal diameter of epicardial coronary arteries was assessed by quantitative angiography.


RESULTS
L-arginine administration significantly increased the diameter of all the coronary segments and stenoses. During atrial pacing with saline infusion, luminal diameter of the proximal, distal, and stenosis reference segments increased significantly (p < 0.01 versus saline) but stenosis diameter did not change. L-arginine administration did not change the magnitude (NS) of atrial pacing induced dilatation in proximal and distal segments and in coronary stenoses and their reference segments.


CONCLUSIONS
Non-stenotic segments of diseased coronary arteries dilate in response to atrial pacing but stenoses do not. L-arginine dilates coronary segments and stenoses but does not increase the magnitude of the response to atrial pacing in proximal and distal segments and in coronary stenoses and their reference segments. These findings provide evidence that the shear stress responsive mechanism is absent at stenoses but present in non-stenotic segments of diseased coronary arteries. They also indicate a relative deficiency of L-arginine, except in the shear response mechanism.
Tousoulis
D
D
Cardiology Unit, Hippokration Hospital, Athens University Medical School, Greece.
Davies
G J
GJ
Tentolouris
C
C
Crake
T
T
Goumas
G
G
Stefanadis
C
C
Toutouzas
P
P
D000787:Angina Pectoris / Q000503:physiopathology / Q000628:therapy*; D001120:Arginine / Q000627:therapeutic use*; D001783:Blood Flow Velocity; D002304:Cardiac Pacing, Artificial; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000187:drug effects*; D003327:Coronary Disease / Q000503:physiopathology / Q000628:therapy*; D023921:Coronary Stenosis / Q000188:drug therapy / Q000503:physiopathology; D003331:Coronary Vessels / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014665:Vasodilator Agents / Q000627:therapeutic use*
D014665:Vasodilator Agents; D001120:Arginine