Certified Cardiographic Technician (CCT) Practice Exam 2025 - Free CCT Practice Questions and Study Guide

The presence of significant Q waves on an electrocardiogram (EKG) is a clear marker of a past transmural myocardial infarction (MI), commonly referred to as a heart attack. A transmural MI affects the full thickness of the heart wall and results in the necrosis of heart tissue. As this damaged tissue heals, the EKG reflects these changes, specifically through the formation of significant Q waves, which are deeper and wider than normal Q waves.

These Q waves indicate that there has been a loss of electrical activity in the affected area of the heart muscle, and they do not typically resolve over time; instead, they persist as a lasting sign of the infarction. This characteristic makes them distinct from other EKG changes. For example, while inverted T waves and ST segment changes may be transient, particularly as the heart recovers from ischemic events, significant Q waves remain evident on future EKGs.

In summary, the significant Q waves serve as a permanent marker of past myocardial damage, differentiating them from other changes that may be temporary and associated with ongoing ischemia or recovery processes.