Background: The extent of Q wave 'burden' on electrocardiograms (ECGs) has not been correlated with the extent of scarring and hibernation as determined quantitatively by positron emission tomography (PET).
Objective: A retrospective study was performed to identify if ECG Q wave burden predicts the extent of scarring or mismatch (hibernating myocardium) as defined by rubidium-82/F-18 fluorodeoxyglucose PET viability imaging.
Patients and methods: Eighty-three consecutive patients with coronary artery disease undergoing rubidium-82/F-18 fluoro-deoxyglucose viability imaging (mean age 67.9+/-11 years, with a mean ejection fraction of 27+/-7%) formed the study population. Resting ECG was interpreted for the presence or absence of Q waves using standard ECG criteria for Q wave myocardial infarction. Patients were divided into two groups based on their Q wave burden on ECG (small to moderate scar: zero to four Q waves; large scar: five or more Q waves). Automated analysis was used to calculate the extent of scarring and mismatch (hibernating myocardium) on PET as a percentage of left ventricular myocardium. Mean PET scar and mismatch scores were calculated for the two groups.
Results: The mean PET scar scores were significantly different between the small to moderate ECG scar group (13.9+/-7.3% of the left ventricle) and the large scar group (20.6+/-8.1% of the left ventricle; P=0.001). The mismatch scores for the small to moderate scar group (4.6+/-2.8%) were not significantly different from those of the large scar group (4.05+/-2.8%; P=0.7).
Conclusions: ECG Q wave 'burden' was associated with the presence of scars as defined by PET but did not accurately predict the amount of hibernating myocardium.