Terminal QRS complex distortion on the admission electrocardiogram in anterior acute myocardial infarction and association with residual flow and infarct size after primary angioplasty

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. ^99mTc-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 II (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 II (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 II (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.