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.