Abstract
BACKGROUND: Terminal QRS complex distortion on admission is a simple and reliable predictor of infarct size in patients with acute myocardial infarction (AMI). It is uncertain, however, whether this reflects reduced myocardial perfusion of the infarct area and a larger area of the myocardium at risk. This study was conducted to investigate whether terminal QRS distortion complex on admission is a reliable predictor of reduced residual flow and a larger area of the myocardium at risk compared to patients who are admitted without a terminal QRS distortion. METHODS: We evaluated the relationship between terminal QRS complex distortion and residual flow to the infarct zone and risk area in 46 anterior AMI patients undergoing primary angioplasty. (99m)Tc-sestamibi imaging was performed at baseline and 5-9 days after angioplasty. The study population was divided into those with (Group I, n=16) and without (Group II, n=30) terminal QRS complex distortion. RESULTS: Baseline characteristics were similar between the two groups. The area of the myocardium at risk was higher in Group I (59.9 +/- 15.3%) than in Group 11 (48.6 +/- 13.7%, p < 0.05; mean+SD) while the nadir measurement of the residual flow was lower in Group I (0.10 +/- 0.07) than in Group 11 (0.16 +/- 0.09, p < 0.05). Although the final infarct size was significantly higher in Group I (40.8 +/- 17.2%) than in Group 11 (27.1 +/- 18.1%, p < 0.05), the myocardial salvage index did not differ significantly between the two groups. CONCLUSION: Terminal QRS complex distortion seems to be associated with less residual flow to the infarct zone, a larger risk area and greater infarct size in patients with anterior AMI.