1. Electrocardiography A Brief Overview of ECG Interpretation

2. Normal to Abnormal Only way to understand abnormal is to first look at the “normal”. First: looking at cardiac electrical conduction.

3. Conduction System Sinoatrial Node Atrioventricular Node Bundle of His Bundle Branches Perkinje Fibres

4. Conduction System Sinoatrial Node (60-80 bpm) Atrioventricular Node (40-60 bpm) Bundle of His (20-40 bpm) Bundle Branches Purkinje fibres Cardiac Cells

5. Normal Conduction SA node starts action Accepted by AV node, starts inferior action Passes to bundle of His, down Purkinje fibres Action potential restarts

6. Cardiac Cell Regular Muscle cells many more Nuclei per cell, whereas cardiac Muscle cells only have one. Much more like smooth muscle, Under involuntary control.

7. Cardiac Cell

8. Muscle Cell

9. Conductivity Contractile and Conductive cells Focused impulse is generated (a pacemaker of any other site) then surrounding tissue will rhythmically contract. Bad when not starting at node.

10. Normal ECG

12. Dysrhythmias Look at P Wave Look at QRS complex Look at T Wave Look for U Waves

13. Rhythm Rate In order to tell what the rate of the heart is from the ECG: Count the # of QRS complexes in a six second strip and multiply by ten.

14. Dysrhythmias Rate P Waves (present, inverted, absent, retrograde, ratio) PR Interval (5 small squares) QRS (3 small squares) Rhythm (regular/irregular)

15. Interpret me!

16. Now me!

17. Heart Disease #1 killer in Canada

18. Blocked Coronary Artery depending on the amount of damage, conductive system may be impaired. electrical impulses do not travel across dead tissue.

19. Defibrillation Reboot the computer

20. Defibrillation Definition - the application of an external electrical shock to the heart muscle which terminates the electrical activity of the heart. This allows the natural pacemakers of the heart to restore normal rhythm. Time from collapse to defibrillation is critical factor to survival

21. Ventricular Tachycardia

22. Ventricular Fibrillation

23. Non-Shockable Rhythms

24. 12 Lead Normally look at Lead II (over Left shoulder) Sometimes need to look at more aspects of heart Used to diagnose myocardial infarction, other cardiac dysrhythmias Looks at 12 Different aspects of the heart

25. 12 Lead

26. Questions?