Abstract 2484: Fragmented QRS on a 12-lead ECG is a Sign of Acute or Recent Myocardial Infarction
Background: ST elevation and Q wave are highly specific signs of myocardial infarction (MI), but there is no specific ECG signs of non-Q wave MI. Fragmented QRS (fQRS) on a 12-lead ECG represents myocardial conduction delays due to the presence of myocardial scar in patients with coronary artery disease. We postulate that fQRS on a 12-lead ECG represents recent MI.
Methods: Serial ECGs of 200 patients (age 64±11 yrs; male 195), with acute MI were compared with the ECGs of 100 patients (age, 60±9 yrs; male, 98. p=NS) without MI or obstructive CAD on coronary angiography (control group). MI was diagnosed by history and elevated cardiac enzymes, and correlated with cardiac catheterization. All patients had ECGs at least 6 months prior to MI. Serial ECGs were obtained 8 hourly during the MI, on day 1 post-catheterization, and 15 days to 6 months (median: 29 days) after the MI. The fQRS on 12-lead ECG was defined by the presence of fragmented QRS, notched R or S wave, or RSR‘ pattern without any bundle branch block, in at least 2 contiguous leads in one of the coronary artery territories (LAD: lead V1 to V6, LCx: lead I, aVL and V6, and RCA: lead II, III and aVF).
Results: A new fQRS and Q wave developed in 61.5% and 27.5% of all patients with MIs (n=200 p <0.001)), 58.7% and 23.3% of non-ST elevation MIs (n=150, p<0.001), and 70% and 40% of ST elevation MIs (n=50, p0.001), respectively.
Conclusion: fQRS is a specific and moderately sensitive sign of acute or recent MI. Incidence of fQRS is significantly higher than Q waves and, more importantly, fQRS is the only sign of non ST elevation MI.