RECOVERY OF IMPAIRED LEFT-VENTRICULAR FUNCTION IN PATIENTS WITH ACUTEMYOCARDIAL-INFARCTION IS PREDICTED BY THE DISCORDANCE IN DEFECT SIZE ON I-123 BMIPP AND TL-201 SPET IMAGES

A discrepancy between myocardial perfusion defect and wall motion abno rmalities is frequently found early after coronary reperfusion in pati ents with acute myocardial infarction. The purpose of this study was t o assess recovery of impaired left ventricular function by reference t o the discordance in defect size between myocardial fatty acid uptake and myocardial perfusion using combined single-photon emission tomogra phic (SPET) imaging early after coronary perfusion therapy. In 37 pati ents with acute myocardial infarction, iodine-123 15-(p-iodophenyl)-3( R, S)-methylpentadecanoic acid (BMIPP) and thallium-201 SPET scans wer e performed early after coronary reperfusion. A severity score was det ermined from the extent of the imaging defect with each tracer. Left v entricular wall motion score (WMS) and ejection fraction (EF) were obt ained at admission and at 4 weeks after the onset of infarction. In 32 of the 37 patients, discordance in defect sizes delineated with the t wo SPET studies was found during the acute stage. The severity score f or BMIPP was larger than that for Tl-201 during the acute stage (7.7+/ -2.4 vs 4.4+/-2.5, P <0.001), There was a fair correlation between the severity score for BMIPP and WMS (r=0.82, P <0.0001), but a poor corr elation between that for Tl-201 and WMS. The extent of discordance in severity scores between BMIPP and Tl-201 during the acute stage correl ated well with the extent of the improvement in WMS (r=0.86, P <0.0001 )and that of EF (r=0.85, P <0.0001). We conclude that the discordance in defect size on BMIPP and Tl-201 SPET images during the acute stage of infarction is an early predictor of the viability of the myocardium at risk of infarction.