The electrical conduction of the heart starts from the SA node. Usually this is called the pacemaker site. When the SA node generates electricity, the atrium contracts.

As the electricity goes into the AV node, the electricity goes to ventricles making the ventricles contract.

This electrical conduction can be seen by the use of an electrocardiogram. Electrodes are place at the chest and the electrical conduction can be seen on an ECG monitor.

The electrical conduction can printed on an ECG paper. Several areas of the hearts electrical conduction can be diagnosed depending on the the number of ECG leads. Usually, the 12 lead ECG would give you a clearer picture of the whole electrical conduction from all angles of the heart.

With these procedure, the doctor can see any aryhtmia or abnormal rhythm and will be able to give medications or do necesarry action to treat the patient.

Below is a video of the Electrical Conduction fo the heart