Answer the following Q with stream of consciousness. Context: In electrocardiography, the PR interval is the period, measured in milliseconds, that extends from the beginning of the P wave (the onset of atrial depolarization) until the beginning of the QRS complex (the onset of ventricular depolarization); it is normally between 120 and 200ms in duration. The PR interval is sometimes termed the PQ interval.

Question: what is the significance of the pq interval?
To answer the question, consider the following: In electrocardiography, the PR interval is the period, measured in milliseconds, that extends from the beginning of the P wave (the onset of atrial depolarization) until the beginning of the QRS complex (the onset of ventricular depolarization); it is normally between 120 and 200ms in duration. Therefore, the final answer is the period , measured in milliseconds , that extends from the beginning of the P wave ( the onset of atrial depolarization ) until the beginning of the QRS complex ( the onset of ventricular depolarization ).