Septal Q wave in exercise testing: evaluation by single-photon emission computed tomography.

Area of Science:

• Cardiology
• Nuclear Cardiology
• Diagnostic Imaging

Background:

• Septal Q waves in lead V5 can change with exercise.
• Coronary artery disease (CAD) diagnosis often involves assessing myocardial perfusion.
• Left anterior descending (LAD) coronary artery disease is a common and significant finding.

Purpose of the Study:

• To evaluate the relationship between exercise-induced changes in septal Q waves and myocardial perfusion defects.
• To determine if septal Q wave alterations can predict LAD coronary artery disease.

Main Methods:

• Single-photon emission computed tomography (SPECT) was used to assess myocardial perfusion.
• Patients were categorized into groups based on septal Q wave changes during exercise (regression, progression/no change, or none).
• Septal perfusion defects were quantified as a percentage of the total septum.

Main Results:

• Patients with Q wave regression during exercise (Group A) showed a high prevalence (94%) of septal perfusion defects and LAD stenosis.
• Patients with no Q wave changes (Group B) had a low prevalence of septal perfusion defects (10%).
• Patients with no Q waves at rest or exercise (Group C) with LAD lesions showed a high rate of septal perfusion defects (91%).
• The area of septal perfusion defects was significantly larger in Group A and Group C compared to Group B.

Conclusions:

• Exercise-induced regression of septal Q waves in lead V5 is a strong indicator of LAD stenosis and associated septal perfusion defects.
• SPECT imaging can effectively identify perfusion abnormalities correlating with Q wave changes.
• These findings suggest that septal Q wave dynamics during exercise are valuable in diagnosing significant coronary artery disease, particularly involving the LAD territory.