Final answer:
Significant Q waves on an ECG may indicate a previous myocardial infarction, but other factors must be considered for a diagnosis. AVR lead should be omitted when checking for significant Q waves.
Step-by-step explanation:
When checking for a myocardial infarction (MI) on an ECG, you should omit the AVR lead when assessing the presence of significant Q waves. Significant Q waves are defined as being 1 mm wide or 1/3 of the QRS complex. A significant Q wave can indicate a previous MI. However, it is important to note that the presence of Q waves alone is not enough to diagnose an MI; other ECG changes and clinical symptoms must also be considered. It is best to consult a healthcare professional for a comprehensive evaluation.