Morphologic correlate of pathologic Q waves as assessed by gradient-echo magnetic resonance imaging

Area of Science:

• Cardiology
• Radiology
• Medical Imaging

Background:

• Pathologic Q waves on electrocardiograms (ECG) are a key indicator of myocardial infarction.
• The extent and transmurality of myocardial scar are crucial in assessing infarct severity and prognosis.
• Gradient-echo magnetic resonance imaging (MRI) offers high-resolution visualization of myocardial tissue characteristics.

Purpose of the Study:

• To correlate the presence or absence of ECG-defined pathologic Q waves with the extent of myocardial scar identified by MRI.
• To investigate the morphologic basis of Q-wave versus non-Q-wave myocardial infarction using advanced imaging techniques.

Main Methods:

• Studied 30 patients with Q-wave infarction, 17 with non-Q-wave infarction, and 15 controls using gradient-echo MRI.
• Assessed myocardial segments for transmural scar based on end-diastolic wall thickness and systolic wall thickening criteria.
• Defined transmural infarcts as those with at least one segment meeting transmural scar criteria.

Main Results:

• 87% of patients with Q-wave infarction showed transmural defects on MRI.
• 35% of patients with non-Q-wave infarction had transmural infarcts.
• Patients with Q-wave infarction had significantly more scar segments (27%) compared to non-Q-wave infarction (7%).

Conclusions:

• Pathologic Q waves on ECG are a strong predictor of transmural myocardial infarction.
• MRI provides detailed morphologic assessment, differentiating infarct transmurality and scar burden.
• The findings highlight the utility of ECG in conjunction with MRI for comprehensive myocardial infarction evaluation.