The P Wave in an Electrocardiogram Results From

Question

The P wave in an electrocardiogram results from
A) depolarization of the ventricles
B) depolarization of the atria
C) repolarization of the ventricles
D) repolarization of the atria

Accepted Answer

The P wave in an electrocardiogram (ECG or EKG) results from the depolarization of the atria. This represents the electrical activity that causes the upper chambers of the heart (the atria) to contract and push blood into the lower chambers (the ventricles). It is the first wave in the ECG tracing and indicates the initiation of the cardiac cycle.