Final answer:
The two significant intervals in an ECG are the PR interval, indicating the time for the electrical signal to travel from atrial to ventricular activation, and the QT interval, representing the total time of ventricular depolarization and repolarization.
Step-by-step explanation:
The two major intervals in an ECG (EKG) are the PR interval and the QT interval. The PR interval measures the time from the beginning of atrial depolarization, indicated by the P wave, to the initiation of the QRS complex, which signifies the start of ventricular depolarization. It reflects the time the electrical impulse takes to travel from the sinus node through the atria, AV node, and His-Purkinje system to activate the ventricles. If there is a delay in the impulse conduction, it would be observed in the PR interval. The QT interval, starting from the beginning of the QRS complex to the end of the T wave, includes the entire period of ventricular depolarization and repolarization. It represents the time during which the ventricles are excited and then recovering.