Electrical Conductive System of the Heart

By: Sarp

Purkinje Fibers• These fibers are specialized myocardial fibers that conduct an

electrical stimulus or impulse.

The SA node

• The SA node starts everysignal that goes through the heart.

The SA node

• It runs the heart at 60-100 bpm.

The AV node

• It gets a signal from the SA node.• If it doesn’t, then it decidesto take charge.

The AV node

• It runs the heart at 40-60 bpm.

The Muscle

• If they don’t get a signal from the AV nodethey contract on their own, at <40 bpm.

What is this?

EKG (Electrokardiogram) or ECG (Electrocardiogram)

• P wave = atrial systole• QRS complex = ventricular systole• T wave = ventricularrepolarization

EKG (Electrokardiogram) or ECG (Electrocardiogram)

• The P wave represents anelectrical signal going from the SAnode to the AVnode

EKG (Electrokardiogram) or ECG (Electrocardiogram)

• The QRS complex represents the electrical signal going

through the Purkinje fibers and back trough the heart muscle.

EKG (Electrokardiogram) or ECG (Electrocardiogram)

• The T wave is the repolarization of the ventricles.

• Remember the Action potential?