1. Heart Conduction System

2. Cardiac Muscle cells contract as a unit
Designed to conduct electrical signals
SA (Sinoatrial) Node (pacemaker)- - -located in wall of Rt Atrium -generates an electrical impulse that spreads out over both atria.
Both atria contract (syncytium) and stimulate the AV (atrioventricular) node to send an impulse.

3. AV (atrioventricular) node-
located in the wall of the interatrial septum.
sends a signal down the A-V Bundle ( bundle of His) (interventricular septum).
A-V Bundle ( bundle of His) branches into (Purkinje Fibers) that spread out over the ventricles and stimulate simultaneous contraction (vent. syncytium).

5. Cardiac conduction system Anatomy Video MedlinePlus http://www.youtube.com/watch?v=bxKBQqe_Bo0

6. When Problems start to arise…..
SA Node – stimulates contraction at a rate of beats/minute
*If the SA Node fails, the AV Node can take over
AV Node – stimulates contraction at a rate of beats/minute
*If the AV Node fails, the Purkinje Fibers can take over
Purkinje fibers – stimulate contraction at a rate of beats/minute

7. NEED FOR THE ARTIFICIAL PACEMAKER…..

8. Getting a Pacemaker surgery http://www.youtube.com/watch?v=WNN4Fw2EWxI

9. EKG/ECG SA Node – triggers impulse – atrial depolarization (P-Wave)
Electrocardiogram – records electrical impulses of the myocardium
SA Node – triggers impulse – atrial depolarization (P-Wave)
Ventricular depolarization – (QRS complex) – atrial repolarization occurs at the same time – but it is smaller than the QRS deflection and is not seen
Ventricular repolarization – (T wave)

10. Cardiac conduction system and relation to EKG

12. Tachycardia – increased heart rate (greater than 100 BPM)
Cardiac Rate
Tachycardia – increased heart rate (greater than 100 BPM)
Bradycardia – decreased heart rate (less than 60 BPM)
Flutter – very rapid HR ( BPM)
Fibrillation – rapid, uncoordinated heart actions