RELATION BETWEEN CARDIAC INDEX AND REGIONAL MYOCARDIAL BLOOD-FLOW IN THE NONINFARCTED WALL USING PET WITH (NH3)-N-13 IN HEALED MYOCARDIAL-INFARCTION

It is not clear whether there is any relationship between cardiac outp ut and myocardial blood flow in the infarcted heart. We measured regio nal myocardial blood flow (RMBF) quantitatively by positron emission t omography (PET) with N-13-ammonia at rest in 18 patients with prior my ocardial infarction. RMBF was calculated using the radioactivity in my ocardial tissue measured by PET and the radioactivity of arterial bloo d. Cardiac output was determined by the dilution method using (NH3)-N- 13 as an indicator, and the relation between cardiac output and RMBF w as evaluated at the same time during PET study. There was a good linea r correlation between cardiac index (C.I.) and mean RMBF in non-infarc ted myocardium (r = 0.45, p < 0.05), and non-infarcted size (r = 0.74, p < 0.01). There was an even better linear correlation between C.I. a nd Sigma RMBF (representing the product of mean RMBF and non-infarcted size) as follows: y = 0.016x + 1.94, r = 0.76 (p < 0.001). It was ind icated that the value of C.I. may be related to RMBF of non-infarcted myocardium and its size (Jpn Heart J 36: 283-292, 1995).