Prognostic Significance of QRS Fragmentation and Correlation with Infarct Size in Patients with Anterior ST-segment Elevation Myocardial Infarction Treated with Percutaneous Coronary Intervention: Insights from the INFUSE-AMI Trial

Background: QRS fragmentation (fQRS) is believed to reflect myocardial scar formation in patients with coronary disease. Whether early formation of fQRS in patients with ST-segment elevation myocardial infarction (STEMI) treated with percutaneous coronary intervention (PCI) is correlated with infarct size and prognosis is unknown. We assessed the prognostic value of fQRS at 60min post-PCI and its correlation with infarct size in patients with anterior STEMI managed with primary PCI.

Methods: The INFUSE-AMI trial enrolled 452 patients with anterior STEMI undergoing primary PCI. Electrocardiograms (ECGs) were performed at baseline and 60min post-PCI. Infarct size was evaluated using cardiac magnetic resonance imaging at 30days post-PCI. Target vessel failure (TVF) was defined as the composite of cardiac death, target vessel myocardial infarction, or ischemia-driven target vessel revascularization. Study groups were defined as patients with versus without fQRS at 60min post-PCI.

Results: Out of 421 patients with ECG data 60min post-PCI, 68 patients (16.2%) had fQRS. Patients with versus without fQRS had similar baseline characteristics and infarct size (16.9%±8.7% vs. 16.1%±10.5%, p=0.62), but patients with fQRS had higher adjusted risk of 1-year TVF (adjusted HR 2.27, 95% CI 1.06-4.89, p=0.036) and a trend toward a higher risk of the composite cardiac death or target vessel myocardial infarction (9.0% vs. 4.1%, p=0.08) at 1year.

Conclusion: fQRS in patients with STEMI is associated with TVF but does not correlate with infarct size.