Abstract
PURPOSE
A surface 12-lead electrocardiogram (ECG) is widely available, fast, inexpensive, and safe. However, its value to predict a true myocardial scar in patients with ischemic cardiomyopathy (ICM) has not been studied extensively yet. This study was conducted to assess whether Q waves on resting surface 12-lead ECG are predictive of non-viable myocardium in patients with ICM.
METHODS
We analyzed resting ECGs of 149 patients with ICM undergoing cardiac positron emission tomography (PET) with 13N-ammonia (NH$_{3}$) and 18F-fluorodeoxyglucose (FDG) at our institution. Pathological Q waves and QS complexes were assigned to one of three coronary artery territories and compared to the PET findings. Myocardial scar was defined as 2 or more contiguous myocardial segments with an average (matched) reduction of NH$_{3}$ and FDG uptake <50% of the maximum value.
RESULTS
Pathological Q waves had a sensitivity and specificity of 70% and 40%, respectively, and a PPV and NPV of 37% and 73%, respectively, to detect myocardial scar on FDG PET. For QS complexes, sensitivity and specificity were 46% and 59%, respectively, and PPV and NPV were 36% and 68%, respectively. Sensitivity was lower, but specificity was significantly higher in both the LCX and RCA compared to the LAD territory (p<0.001), particularly for QS complexes.
CONCLUSION
Pathological Q waves on resting 12-lead ECG have poor or at best moderate sensitivity and specificity to detect myocardial scar on FDG PET. These findings support the use of more advanced imaging techniques to assess myocardial viability in ICM.
Markendorf, Susanne