P-wave | T-wave | |
1 | In an electrocardiogram (ECG), the P-wave indicates the activation of the SA node. | In an electrocardiogram (ECG), the T-wave represents ventricular relaxation. |
2 | During this phase, the impulse of contraction is generated by the SA node, causing atrial depolarization. | During this phase, the ventricles relax and return to their normal state. |
3 | It is of atrial origin. | It is of ventricular origin. |