Certified Cardiovascular Technician Practice Exam

What factor can interfere with electrocardiogram results?

1. Skin temperature

2. Blood pressure

3. Medications

4. Heart rate

The correct answer is: Medications

Medications can significantly interfere with electrocardiogram (ECG) results because they have the potential to affect the heart's electrical conduction system and the overall cardiac function. Certain medications, such as antiarrhythmics, beta-blockers, and certain antidepressants, can alter the heart's rhythm, prolong the QT interval, or cause other changes in the heart's electrical activity. These changes can manifest as deviations in the ECG tracing, leading to inaccurate interpretations of the heart's condition. While factors like skin temperature, blood pressure, and heart rate certainly play important roles in the overall assessment of a patient's cardiovascular status, their direct influence on the raw ECG results is less pronounced than that of medications. Skin temperature can affect skin conductivity and potentially the quality of the ECG leads, but it doesn’t change the fundamental electrical activity of the heart. Blood pressure is vital for assessing cardiac function but does not directly alter the electrical patterns on the ECG. Heart rate affects the frequency of the ECG waves but is essentially a reflection of both normal physiological responses and the body's current cardiac condition rather than a direct disruptor of the ECG output caused by foreign substances. Thus, when considering the direct influences on the electrical signals recorded by an ECG, medications are particularly critical, making