unit 4 - ECG and Heart sounds

What can happen if the SA node is defective?

The AV node takes over, producing junctional rhythm at ~ 50 bpm.

What can a defective AV node cause?

Partial or total heart block

What happens with a defective AV node?

few impulses get through

What is an electrocardiograph (ECG)?

A visual tracing that depicts the activity of the heart based on electrical signals.

What does the P wave represent?

Atrial depolarization.

What does the QRS complex represent?

Atrial repolarization and ventricular depolarization.

What does the T wave represent?

Ventricular repolarization.

What are the two main heart sounds?

LUB and DUB

What causes the LUB heart sound?

Closure of the AV valves.

What phase of the cardiac cycle begins with the LUB sound?

Ventricular systole, or contraction.

What causes the DUB heart sound?

Closure of the semilunar valves.

What phase of the cardiac cycle begins with the DUB sound?

Ventricular diastole, or relaxation.