Certified Cardiovascular Technician Practice Exam

A negative P wave likely indicates what?

1. It originates from the SA node

2. It originates from the atrioventricular node

3. It originates from an area outside the SA node

4. It is a normal variation

The correct answer is: It originates from an area outside the SA node

A negative P wave is indicative of depolarization originating from an area outside the sinoatrial (SA) node. Normally, the P wave reflects the electrical activity as it spreads through the atria, starting at the SA node. When the P wave is negative, it often suggests that the impulse is arising from a different pacemaker within the heart, such as an ectopic atrial focus or from the atrioventricular (AV) node as the primary pacemaker. In the context of the provided choices, the negative P wave signifies that the electrical activity is being initiated not from the traditional starting point (the SA node), but instead from an alternate site. This can lead to variations in the shape and polarity of the P wave observed on an electrocardiogram (ECG), which is crucial for diagnosing certain arrhythmias or conduction pathways that may not function optimally. The normal variation in heart rhythm would typically feature a positive P wave, thereby distinguishing the occurrence of a negative P wave as an anomaly that must be further investigated.