Final answer:
A deep wide Q wave on an ECG typically indicates a myocardial infarction (MI), also known as a heart attack.
Step-by-step explanation:
A deep wide Q wave on an ECG typically indicates a myocardial infarction (MI), also known as a heart attack. An MI occurs when there is a blockage in the blood flow to a part of the heart, leading to damage of the heart muscle. The Q wave represents the depolarization of the ventricles, and a deep wide Q wave suggests significant damage to the heart muscle.