Abstract 2485: The Endocardial Extent of Reperfused Myocardial Infarction is a Stronger Determinant of Pathological Q Waves than is Infarct Transmurality
Introduction: The pathologic basis of Q waves on the electrocardiogram (ECG) after myocardial infarction (MI) is still controversial. MI transmurality has recently been shown not to be as closely related to Q-wave MI as previously reported. Given that the first part of the QRS complex reflects depolarization of subendocardial myocardium, endocardial extent of MI is a potential determinant of pathological Q waves.
Hypothesis: The endocardial extent of MI is more predictive of pathological Q waves than is MI transmurality.
Methods: Twenty-nine patients with reperfused first-time MI were prospectively enrolled. One week after admission, delayed contrast-enhanced magnetic resonance imaging (DE-MRI) was performed and 12-lead ECG was recorded. Size, transmurality and endocardial extent of MI were assessed by DE-MRI. Q waves were identified according to Minnesota coding.
Results: There was a significant difference between patients with and without Q waves with regard to MI size (p = 0.03) (Fig A⇓) and endocardial extent of MI (p = 0.01) (Fig D⇓), but not to mean and maximum MI transmurality (p = 0.09 and p = 0.14) (Fig B-C⇓). Endocardial extent was the only independent predictor of pathological Q waves.
Conclusions: The endocardial extent of reperfused first-time acute MI is more predictive of pathological Q waves than is MI transmurality.