IDENTIFICATION OF VIABLE MYOCARDIUM IN PATIENTS WITH CHRONIC CORONARY-ARTERY DISEASE AND LEFT-VENTRICULAR DYSFUNCTION - ROLE OF MAGNETIC-RESONANCE-IMAGING

Nineteen patients (16 men and 3 women, mean age 51 years) with previou s anterior myocardial infarction and severe stenosis (greater than or equal to 90%) of the left anterior descending coronary artery were stu died by magnetic resonance imaging (MRI) without and with contrast med ia to verify the capability of MRI in identifying viable myocardium in areas of severe systolic dysfunction. In corresponding left ventricul ar segments, a comparison was made between regional signal intensities (SI) determined on MRI images before and 4, 8, 12, and 30 minutes aft er administration of paramagnetic contrast media (gadolinium di 0.4 mm ol/kg intravenously) and metabolic parameters determined by iodine 123 phenylpentadecanoic acid (IPPA) scintigraphy. The SI and the time of maximum postcontrast enhancement were analyzed by dividing the left ve ntricle into 11 segments. Each segment was classified as normal (group 1, n = 116), hibernating (group 2, n = 50), or necrotic (group 3, n = 43) on the basis of the IPPA washout rate (>30%, 10% to 30%, and <10% , respectively). Regional SI demonstrated significant differences in a bsolute values at 12 minutes (group 3: 1.62 +/- 0.58 vs group 1: 1.32 +/- 0.52, p < 0.01, and vs group 2: 1.34 +/- 0.48, p < 0.05) and at 30 minutes (group 3: 1.71 +/- 0.47 vs group 1: 1.21 +/- 0.55, p < 0.01, and vs group 2: 1.49 +/- 0.57, p < 0.05) and in temporal distribution. These results suggest that MRI has a potential role in differentiatin g viable from necrotic myocardium in patients with chronic severe syst olic dysfunction.