Cardiac adrenergic denervation in patients with non-Q-wave versus Q-wave myocardial infarction.
In spite of smaller infarct size and better preserved left ventricular function the long-term prognosis after a non-Q-wave infarction is not better than after a Q-wave infarction. In fact, the risk of sudden cardiac death is higher in patients with a non-Q-wave infarction than in patients with a Q-wave infarction. One possible reason for postinfarction arrhythmias is cardiac adrenergic denervation resulting from myocardial infarction. In this study we compared cardiac adrenergic innervation after non-Q-wave and Q-wave infarctions. Single-photon emission tomography using iodine-123 metaiodobentzylguanidine (MIBG) and technetium-99m sestamibi (MIBI) tracers were conducted in order to compare cardiac adrenergic denervation and myocardial perfusion in 12 patients with a non-Q-wave infarction and 15 patients with a Q-wave infarction. MIBG and MIBI defects were determined as regional uptake < or = 30% of maximal myocardial activity. The size of MIBI defects calculated as a percentage of left ventricular mass was significantly smaller in patients with a non-Q-wave infarction than in patients with a Q-wave infarction (4%+/-3% vs 9%+/-7%, P<0.05, respectively). According to the maximal serum creatine kinase activity, less myocardium was damaged in patients with a non-Q-wave infarction than in patients with a Q-wave infarction (502+/-436 IU/l vs 1878+/-1265 IU/l, P<0.001). In spite of this, the extent of MIBG defects was similar in patients with a non-Q-wave and patients with a Q-wave infarction (21%+/-18% vs 23%+/-12%, respectively). In addition, the size of MIBG defect correlated with the infarct size (maximal creatine kinase activity) (r=0.52, P<0.05) after a Q-wave infarction but not after a non-Q-wave infarction. In conclusion, despite a smaller infarct size in non-Q-wave infarct patients, the extent of cardiac adrenergic denervation was similar in patients with a non-Q-wave and patients with a Q-wave infarction. In addition, the extent of cardiac adrenergic denervation was related to the infarct size in patients with a Q-wave infarction but not in patients with a non-Q-wave infarction.
Simula
S
S
Department of Medicine, Kuopio University Hospital, Finland.
Lakka
T
T
Laitinen
T
T
Remes
J
J
Kettunen
R
R
Kuikka
J
J
Hartikainen
J
J
D019797:3-Iodobenzylguanidine; D016022:Case-Control Studies; D003402:Creatine Kinase / Q000097:blood; D004562:Electrocardiography; D005080:Exercise Test; D006321:Heart / Q000000981:diagnostic imaging / Q000294:innervation*; D006801:Humans; D007457:Iodine Radioisotopes; D007527:Isoenzymes / Q000097:blood; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000503:physiopathology; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon
D007457:Iodine Radioisotopes; D007527:Isoenzymes; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine; D017256:Technetium Tc 99m Sestamibi; D003402:Creatine Kinase