ECG course for the Medical Students and junior physicians.

1. Dr. Abdulkadir Insi, MD

2. Anatomy of the Heart
June 22, 2021 ECG intensive course for Medical Students 2

3. • The heart, located in the mediastinum, is the
central structure of the cardiovascular system.
• It is protected by the bony structures of the
sternum anteriorly, the spinal column posteriorly,
and the rib cage.
June 22, 2021 ECG intensive course for Medical Students 3

4. ♥ Clinical Tip
• The cone-shaped heart has its tip (apex) just above
the diaphragm to the left of the midline.
• This is why we may think of the heart as being on
the left side, since the strongest beat can be heard
or felt here.
June 22, 2021 ECG intensive course for Medical Students 4

5. Layers of the Heart
June 22, 2021 ECG intensive course for Medical Students 5

6. ♥ Clinical Tip
• The pericardial cavity contains a small amount of
lubricating fluid to prevent friction during heart
contraction.
June 22, 2021 ECG intensive course for Medical Students 6

7. Heart Valves
Properties of Heart Valves:
■ Fibrous connective tissue prevents enlargement
of valve openings and anchors valve flaps.
■ Valve closure prevents backflow of blood during
and after contraction.
June 22, 2021 ECG intensive course for Medical Students 7

8. June 22, 2021 ECG intensive course for Medical Students 8

9. June 22, 2021 ECG intensive course for Medical Students 9
Cardiac Valves and their functions
The human heart contains four valves
Two atrioventricular valves (AV valves):
• Tricuspid valve
• Mitral or bicuspid valve
Two semilunar valves:
• Aortic valve
• Pulmonary valve

10. June 22, 2021 ECG intensive course for Medical Students 10
Home work
1. Functions of the heart valves
2. Functions of papillary ms
3. Relations between the Heart Sounds and Heart
Pumping

11. Heart Chambers and Great Vessels
June 22, 2021 ECG intensive course for Medical Students 11

12. June 22, 2021 ECG intensive course for Medical Students 12

13. June 22, 2021 ECG intensive course for Medical Students 13

14. CoronaryArterial Circulation
June 22, 2021 ECG intensive course for Medical Students 14

15. Cardiovascular System
• The cardiovascular system is a closed system
consisting of blood vessels and the heart.
• Arteries and veins are connected by smaller
structures in which electrolytes are exchanged
across cell membranes.
June 22, 2021 ECG intensive course for Medical Students 15

16. Blood Vessel Structures
June 22, 2021 ECG intensive course for Medical Students 16

17. June 22, 2021 ECG intensive course for Medical Students 17

18. Arterial Circulation
June 22, 2021 ECG intensive course for Medical Students 18

19. Venous Circulation
June 22, 2021 ECG intensive course for Medical Students 19

20. June 22, 2021 ECG intensive course for Medical Students 20

21. Physiology of the Heart
June 22, 2021 ECG intensive course for Medical Students 21

22. June 22, 2021 ECG intensive course for Medical Students 22

23. Physiology of Atria and Ventricles
June 22, 2021 ECG intensive course for Medical Students 23
REVISE

24. June 22, 2021 ECG intensive course for Medical Students 24

25. June 22, 2021 ECG intensive course for Medical Students 25
End-Diastolic Volume, End-Systolic Volume, and Stroke
Volume Output
• End-diastolic volume: During diastole, the ventricles
increases the volume to about 110 to 120 ml
• The stroke volume output: during systole, the
ventricles empty and the volume decreases about 70 ml
• The end-systolic volume: The remaining volume in
each ventricle, about 40 to 50 ml

26. Factors Influencing CO
June 22, 2021 ECG intensive course for Medical Students 26

27. June 22, 2021 ECG intensive course for Medical Students 27

28. June 22, 2021 ECG intensive course for Medical Students 28
Properties of Cardiac Muscle Fibers
1. Autorhythmicity: The ability to initiate a heart beat
continuously and regularly without external stimulation
2. Excitability: The ability to respond to a stimulus of
adequate strength and duration by generating a
propagated action potential
3. Conductivity: The ability to conduct excitation through
the cardiac tissue
4. Contractility: The ability to contract in response to
stimulation

29. June 22, 2021 ECG intensive course for Medical Students 29
THE CARDIAC MUSCLE
• Contractile muscle fibres (myocardium 99%)
Atrial muscle fibres & Ventricular muscle fibres
- Both contract same as in skeletal Muscle
- Duration of contraction much longer
• Excitatory & conductive muscle fibres (autorhythmic 1%
- Few contractile fibrils (very weak contraction)
- Exhibit either automatic rhythmic discharge(AP)
OR
Conduction of the AP through heart

30. June 22, 2021 ECG intensive course for Medical Students 30
Specialized Excitatory and Conductive System of
the Heart

31. June 22, 2021 ECG intensive course for Medical Students 31
Internodal Pathways

32. Electrical Conduction System of the Heart
June 22, 2021 ECG intensive course for Medical Students 32

33. June 22, 2021 ECG intensive course for Medical Students 33

34. June 22, 2021 ECG intensive course for Medical Students 34
Locations of autorythmic cells
 Sinoatrial node (SA node):
Specialized region in right atrial wall near opening
of superior vena cava.
 Atrioventricular node (AV node) :
Small bundle of specialized cardiac cells located at
base of right atrium near septum.

35. June 22, 2021 ECG intensive course for Medical Students 35
Locations of autorythmic cells …
 Bundle of His (atrioventricular bundle)
oCells originate at AV node & enters interventricular
septum.
oDivides to form right and left bundle branches
which travel down septum, curve around tip of
ventricular chambers and travel back toward atria
along outer walls.

36.  Purkinje fibers
 Small, terminal fibers that extend from
bundle of His and spread throughout ventricular
myocardium.
June 22, 2021 ECG intensive course for Medical Students 36
Locations of autorythmic cells …

37. June 22, 2021 ECG intensive course for Medical Students 37

38. June 22, 2021 ECG intensive course for Medical Students 38

39. Electrical Conduction System of the Heart
June 22, 2021 ECG intensive course for Medical Students 39

40. June 22, 2021 ECG intensive course for Medical Students 40
Action potential in contractile fibers

41. June 22, 2021 ECG intensive course for Medical Students 41

42. June 22, 2021 ECG intensive course for Medical Students 42

43. ♥ Clinical Tip
• Mechanical and electrical functions of the heart are
influenced by proper electrolyte balance.
• Important components of this balance are sodium,
calcium, potassium, and magnesium.
June 22, 2021 ECG intensive course for Medical Students 43

44. ♥ NB:
Revise the Heart Anatomy and Physiology
Again before we enter the 2nd Lecture.
June 22, 2021 ECG intensive course for Medical Students 44