Postexercise ischemia is associated with increased neuropeptide Y in patients with coronary artery disease.
BACKGROUND
Neurohormones may influence vascular tone both during and after exercise. Neuropeptide Y (NPY), which is costored and released with norepinephrine (NE) during sympathetic activity, is a potent vasoconstrictor with a relatively long half-life. We therefore examined its possible association with the ischemic response to exercise in patients with coronary artery disease.


RESULTS
Twenty-nine male patients with effort-induced angina pectoris underwent a symptom-limited exercise test. In addition to conventional ST-segment analysis, we examined ischemia on the basis of heart rate (HR)-adjusted ST-segment changes through calculation of the ST/HR slope during the final 4 minutes of exercise and of the ST/HR recovery loop after exercise. Blood samples were taken before, during, and after exercise for an analysis of several neurohormones. Mean ST-segment depression was -223+/-20.2 microV (P:<0.0001) just before the termination of exercise, followed by a gradual normalization, but it remained significant after 10 minutes (-49+/-8.9 microV, P:<0.0001). At the end of exercise, the ST/HR slope, which reflects myocardial ischemia, was -6.0+/-0.77 microV/HR. In most patients, ST-segment levels at a given HR were lower during recovery than during exercise, here referred to as ST "deficit." Exercise increased the plasma levels of NPY, NE, epinephrine, and N-terminal proatrial natriuretic peptide, but big endothelin remained unchanged. Although NE and epinephrine peaked at maximal exercise, the highest levels of NPY and N-terminal proatrial natriuretic peptide were observed 4 minutes after exercise. The maximal increase in the NPY correlated significantly with ST-segment depression at 3 minutes after exercise (r=-0.61, P:= 0.0005), the ST deficit at the corresponding time point (r=-0.66, P:= 0.0001), and the duration of ST-segment depression after exercise (r= 0.42, P:=0.02). In contrast, no such correlations were found for NE.


CONCLUSIONS
The present study has for the first time demonstrated a correlation between plasma NPY levels and the degree and duration of ST-segment depression after exercise in patients with coronary artery disease, which suggests that NPY may contribute to myocardial ischemia in these patients.
Gullestad
L
L
Department of Cardiology, Rikshospitalet University Hospital, Oslo, Norway. lagulles@online.no
Jorgensen
B
B
Bjuro
T
T
Pernow
J
J
Lundberg
J M
JM
Dota
C D
CD
Hall
C
C
Simonsen
S
S
Ablad
B
B
D000704:Analysis of Variance; D000787:Angina Pectoris / Q000503:physiopathology; D009320:Atrial Natriuretic Factor / Q000097:blood; D003327:Coronary Disease / Q000097:blood / Q000503:physiopathology*; D004562:Electrocardiography; D019332:Endothelin-1; D016232:Endothelins / Q000097:blood; D004837:Epinephrine / Q000097:blood; D005080:Exercise Test; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009478:Neuropeptide Y / Q000097:blood*; D009638:Norepinephrine / Q000097:blood; D011498:Protein Precursors / Q000097:blood; D013997:Time Factors
D019332:Endothelin-1; D016232:Endothelins; C099254:N-terminal proatrial natriuretic peptide; D009478:Neuropeptide Y; D011498:Protein Precursors; D009320:Atrial Natriuretic Factor; D009638:Norepinephrine; D004837:Epinephrine