Cardiac Cycle, Heart Sounds, Cardiac Murmur. Physiology pptx

Cardiac Cycle, Heart Sounds, Cardiac Murmur.pptx

1. CARDIC CYCLE 1 By Dr. BaQir NaQvi DAKSON Institute of Health Sciences, Islamabad

2. LECTURE OUTLI NES / OBJECTIVES General principle of the cardiac cycle Identify events occurring during cardiac cycle: mechanical, electrical, volume & pressure changes, heart sounds. Understand the various phases of the cardiac cycle STUDENTS ABLE TO UNDERSTAND: 2

3. CARDIAC CYCLE The cardiac events that occur from the beginning of one heart beat to the beginning of the next is called the cardiac cycle. Cardiac cycle is a complete beat of the heart. The cardiac cycle consists of a period of relaxation called diastole during which the heart fills with blood. This period is followed by a period of contraction called systole. Each cycle is initiated by spontaneous generation of an action potential in the sinus node (SA node). 3

4. CARDIAC CYCLE: CARDIAC VALVES 4

5. CARDIAC CYCLE: CARDIAC VALVES

6. CARDIAC CYCLE: CARDIAC VALVES

7. PRESSURES IN THE CARDIAC CHABERS Aortic pressure (left ventricular pressure) Maximum pressure (during systole): 120 mm Hg. Minimum pressure (during diastole): 80 mm Hg. Pulse pressure (difference between systolic and diastolic) : 120-80 = 40 mm Hg. Right ventricular pressure  Maximum pressure = 25mm Hg Minimum pressure = 0-2mm Hg Atrial pressure Maximum right atrial pressure 6-8 mm Hg Minimum right atrial pressure 0-2 mm Hg Maximum left atrial pressure 6-9 mm Hg Minimum left atrial pressure 0-2 mm Hg   Pulmonary pressure (mm Hg) Systolic pulmonary arterial pressure: 25 mmHg Diastolic pulmonary arterial pressure : 8 mmHg

8. CARDIAC CYCLE I. VENTRICULAR SYSTOLE Iso -volumetric contraction of ventricles ( 0.05 sec ) Maximum ejection phase (0.112sec) Reduced ejection phase. (0.141 sec ) ------------- 0.303 Sec 2. VENTRICULAR DIASTOLE Protodiastole ( 0. 033 sec) Isovolumetric ( isovolumic ) relaxation (0. 071 sec) Rapid inflow ( 0.110 sec) Reduced inflow (0.161 sec) Atrial systole ( 0.12 sec ) -------------- 0.495 sec. [0.8 Sec] 8

9. Book Ref: Jaypee essentials of medical Physiology, Page 537 9

10. CARDIAC CYCLE: DURATION OF SYSTOLE AND DIASTOLE 0.3Sec. 0.5 sec. VS VD

11. CARDIAC CYCLE: VENTRICULAR SYSTOLE Iso -volumetric contraction Left ventricle begins to contract, at this stage, pressure in the ventricles is slightly above 0-2mm Hg . As the intra-ventricular pressure rises, it pushes the cusps of the A-V valve up and the A-V orifices are closed. The pressure in the ventricular cavities continues to rise but remains less than that in the large arteries. Thus, the semilunar valves (aortic and pulmonary) also remain closed and no blood enters or leaves the ventricles. CARDIAC CYCLE: VENTRICULAR SYSTOLE 11

12. CARDIAC CYCLE: VENTRICULAR SYSTOLE CARDIAC CYCLE: VENTRICULAR SYSTOLE 12

13. 2. MAXIMUM EJECTION PHASE: The ventricles contract and increase the pressure more than in the large arteries. The left ventricular pressure rises up to 120 mm Hg causes the opening of the aortic valves Right ventricular pressure rises more than 25 mm Hg and causes the opening of pulmonary valves so blood leaves the ventricles rapidly to the aorta and pulmonary artery At the end of this stage, intra-ventricular pressure reaches its peak level. CARDIAC CYCLE: VENTRICULAR SYSTOLEc 13

14. 3. REDUCED EJECTION PHASE In this phase of the cardiac cycle, the force of contraction of the ventricles becomes weaker than the force of contraction during the maximum ejection phase. Now the pressure within the ventricles also decreases, but is still higher than that of the aorta so ventricular emptying continues. In this phase less volume of blood flows into the aorta and pulmonary artery due to weaker contraction of the ventricles. CARDIAC CYCLE: VENTRICULAR SYSTOLE 14

15. CARDIAC CYCLE: VENTRICULAR SYSTOLE 15

16. CARDIAC CYCLE: VENTRICULAR SYSTOLE 16

17. Stages of card. Cycle :- 17 Ventricles are relaxed AV Valves are close Atria are relaxed Semilunar valves are closed 1. Vent filling rapidVent filling AV Valves opened

18. Stages of card. Cycle :- 18 Ventricles are relaxed AV Valves are open Atria are relaxed Semilunar valves are closed b. diastasis

19. 20% of ventricular filling Stages of cardiac Cycle :- 19 Ventricles are relaxed AV Valves are open Contraction of Atria Semilunar valves are closed c. Atrial systole.

20. Stages of cardiac Cycle :- 20 Contraction of Ventricles AV Valves are closed Semilunar valves are closed 2. Isovolumic (isometric) ventricular contraction

21. Stages of cardiac Cycle :- 21 Contraction of Ventricles AV Valves are closed Semilunar valves opened 3. Ejection phase The blood will be ejected to the arteries. The Pr. in the aorta =120 mmHg. Pr . in the pulmonary artery= 25 mmHg.

22. The volume of blood in the ventricle at the end of the systole 22 E.D.V. E.S.V. S.V The volume of blood in the ventricle at the end of the diastole (just before ventricular systole started) End diastolic volume End systolic volume The volume of blood ejected per one beat Stroke volume ↑ EDV →↑ SV ↓ SV → ↑ ESV Normally about 70 ml at rest

23. 23 E.F It is the percentage of volume of blood which is ejected from the E.D.V. Ejection fraction E.F= SV ×100% EDV What is the ejection fraction of a left ventricle with EDV of 150ml and SV of 75 ml E.F= SV ×100% EDV = 75 ×100%= 50% 150 Normally about 65%

24. VENTRICULAR DIASTOLE [PROTO DIASTOLE] In this stage, the ventricles relax and the intraventricular pressure decreases, becoming less than the aortic and pulmonary artery pressures. Blood present in the aorta and pulmonary artery tends to move back into the ventricles. At this stage the semilunar valves ( aortic and pulmonary ) are closed and do not allow entry of blood into the ventricles CARDIAC CYCLE: VENTRICULAR DIASTOLE

25. ISOVOLUMETRIC RELAXATION In this stage the ventricles relax further and intraventricular pressure falls. The semilunar valves remain closed due to higher pressure in the large arteries as compared to intraventricular pressure. The pressure within the ventricles is still higher than the atria, so the A-V valves remain closed and no blood enters or leaves the ventricles. CARDIAC CYCLE: VENTRICULAR DIASTOLE

26. CARDIAC CYCLE: VENTRICULAR DIASTOLE 26

27. RAPID INFLOW The ventricular volume increases, the pressure within the ventricles is further decreased to lower than intra atrial pressure. The left ventricular pressure decreases up to 2-4 mm Hg. This pressure is less than the maximum left atrial pressure (6-9mm Hg). This change in pressure causes the opening of left AV (biscuspid / mitral) valve. So blood which was accumulate in the left atrium rush into the left ventricle. CARDIAC CYCLE: VENTRICULAR DIASTOLE

28. RAPID INFLOW Right ventricular pressure decreased up to 0-2mm Hg. This pressure is less than the maximum right atrial pressure (6-8mm Hg). This change in pressure causes the opening of right AV (tricuspid) valve. So the blood which was accumulate in the right atrium rush into the right ventricle. CARDIAC CYCLE: VENTRICULAR DIASTOLE

29. CARDIAC CYCLE: VENTRICULAR DIASTOLE 29

30. CARDIAC CYCLE 30

31. Reduced inflow At the beginning of this phase most of the blood has already entered the ventricles. Remaining blood in the atria also flows into the ventricles. Atrial systole Once again the atrial muscle fibers start to contract, indicating the beginning of a new cardiac cycle. CARDIAC CYCLE: VENTRICULAR DIASTOLE

32. Stages of cardiac Cycle :- 32 Relaxation of Ventricles AV Valves are closed Semilunar valves closed 4. Isovolumic (isometric) ventricular Relaxation

33. Diastole: 33

34. Systole: 34

35. 35 More time for filling of the ventricle More time for relaxation of the coronary arteries

36. 36 pressure(mmHg) Volume (ml) 120 80 50 120 40 Diastolic filling Ejection SV Mitral v open Aortic v open Aortic v close Mitral v close The pressure – volume loop EDV ESV A B C D

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38. SUMMARY CARDIAC CYCLE EVENTS: OPENING AND CLSOSING OF VAVLVES

39. CARDIAC CYCLE: ASSOCIATION WITH HEART SOUNDS 39

40. CARDIAC CYCLE: ASSOCIATION WITH HEART SOUNDS 40

41. CARDIAC CYCLE: ASSOCIATION WITH HEART SOUNDS

42. VS VD CARDIAC CYCLE: ASSOCIATION WITH HEART SOUNDS HEART SOUNDS 0.3Sec. 0.5 sec. 1 st Heart Sound 2 nd Heart Sound 3 rd Heart Sound 4 th Heart Sound AS – Atrial Systole; AD – Atrial Diastole ; VS – Ventricular systole; VD – Ventricular diastole 42

43. Ventricular Systole 0.3Sec. 1 st Heart Sound 2 nd Heart Sound Isovolumetric contraction period Maximum ejection period Reduced ejection period AS – Atrial Systole; AD – Atrial Diastole ; VS – Ventricular systole; VD – Ventricular diastole CARDIAC CYCLE: ASSOCIATION WITH HEART SOUNDS 43

44. Ventricular Diastole 0.5Sec. 1 st HS 2 nd HS Isovolumetric Relaxation Phase Maximum Filling Phase Reduced Filling Phase 4 th HS 3 rd HS HS – Heart Sound Protodiastolic Period CARDIAC CYCLE: ASSOCIATION WITH HEART SOUNDS 44

45. TAKE HOME MESSAGE Beginning of one heart beat to the beginning of the next is called the cardiac cycle. consists of a period of relaxation called diastole followed by period of contraction called systole. Cycle duration is 0.8 Sec [Systole 0.3 sec and Diastole 0.5 Sec] 45

46. 46 Heart Sounds Book Ref: Jaypee essentials of medical Physiology, Page 544-549

47. Heart Sounds “Heart sounds are the sounds produced by mechanical activities of heart during each cardiac cycle .” Heart sounds are produced by: 1 . Flow of blood through cardiac chambers. 2 . Contraction of cardiac muscle. 3 . Closure of valves of the heart. Heart sounds are heard by placing the ear over the chest or by using a stethoscope or microphone. These sounds are also recorded graphically. 47 Book Ref: Jaypee essentials of medical Physiology, Page 544-549

48. „ DIFFERENT HEART SOUNDS Four sounds are produced during each cardiac cycle: 48 Book Ref: Jaypee essentials of medical Physiology, Page 544-549

49. „ DIFFERENT HEART SOUNDS First and second heart sounds are called classical heart sounds and are heard by using the stethoscope . These two sounds are more prominent and resemble the spoken words; 49

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51. Third heart sound is a mild sound and it is not heard by using stethoscope in normal conditions. But it can be heard by using a microphone. Fourth heart sound is an inaudible sound. It becomes audible in pathological conditions only. This sound is studied only by graphic registration, i.e. the phonocardiogram. 51

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53. 53 Book Ref: Jaypee essentials of medical Physiology, Page 544-549

54. TRIPLE AND QUADRUPLE HEART SOUNDS TRIPLE HEART SOUND/GALLOP RHYTHM: Triple rhythm is an abnormal rhythm of heart, characterized by three clear heart sounds during each heart bea t. It is due to an abnormal third or fourth heart sound that is heard besides first and second heart sounds. It is also called gallop rhythm, as it resembles the sound of a horse’s gallop . Usually, it is indicative of serious cardiovascular disease (myocardial infarction or severe hypertension). 54

55. Q uadruple heart sound it is an abnormal rhythm of heart, characterized by four clear heart sounds during each heart beat. It is also called quadruple rhythm. It is due to third and fourth heart sounds that are heard besides first and second heart sounds. It is also called quadruple gallop. Quadruple heart sound is also indicative of serious cardiovascular disease (congestive heart failure). 55 TRIPLE AND QUADRUPLE HEART SOUNDS

56. Summation Gallop Whenever there is tachycardia in patients with quadruple heart sound, the third and fourth heart sounds merge together and give rise to a single sound. This sound is called summation gallop and it resembles gallop rhythm. 56

57. METHODS OF STUDY OF HEART SOUNDS 57 Heart sounds are studied by three methods Book Ref: Jaypee essentials of medical Physiology, Page 544-549

58. BY STETHOSCOPE BY STETHOSCOPE First and second heart sounds are heard on the auscultation areas, by using the stethoscope. The chest piece of the stethoscope is placed over four areas on the chest, which are called auscultation areas. 58

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60. BY MICROPHONE A highly sensitive microphone is placed over the chest. The heart sounds are amplified by means of an amplifier and heard by using a loudspeaker. First , second and third heart sounds are heard by this method. 60

61. BY PHONOCARDIOGRAM Phonocardiography is the technique used to record the heart sounds. Phonocardiogram is the graphical record of heart sounds. It is done by placing an electronic sound transducer over the chest. This transducer is connected to a recording device like polygraph. All the four heart sounds can be recorded in phonocardiogram. It helps to analyze the frequency of the sound waves. 61

62. 62 Book Ref: Jaypee essentials of medical Physiology, Page 549-550

63. Cardiac murmur It is the abnormal or unusual heart sound. It is also called abnormal heart sound or cardiac bruit . Cardiac murmur is heard by stethoscope, along with normal heart sounds. Murmur due to disease of a particular valve is heard well over the auscultatory area of that valve. Sometimes, murmur is felt by palpation as ‘thrills’. In some patients, murmur is heard without any aid, even at a distance of few feet away from the patient. 63

64. CAUSES OF MURMUR Cardiac murmur is produced because of change in the pattern of blood flow. Normally, blood flows in streamline through the heart and blood vessels. D uring abnormal conditions like valvular diseases, the blood flow becomes turbulent. It produces the cardiac murmur. 64

65. Valvular Diseases Valvular diseases are of two types: 1 . Stenosis 2 . Incompetence. 1 . Stenosis Stenosis means narrowing of heart valve. Blood flows rapidly with turbulence through the narrow orifice of the valve, resulting in murmur. 65

66. 2. Incompetence It is weakening of the heart valve. When the valve becomes weak, it cannot close properly. It causes back flow of blood, resulting in turbulence. This disease is also called regurgitation or valvular insufficiency. 66

67. CLASSIFICATION OF MURMUR 67

68. SYSTOLIC MURMUR Systolic murmur is the murmur which is produced during systole. 1 . Incompetence of Atrioventricular Valves When the atrioventricular valves become weak, these valves cannot close completely . 68 It causes regurgitation of blood from ventricles to the atria during ventricular systole, producing the murmur. It is a harsh blowing sound with high frequency .

69. 2. Murmur due to Anemia A systolic murmur is heard in severe anemia because of reduced viscosity and accelerated flow of blood. 69

70. 3. Septal Defect During inter-ventricular septal defect, blood flows from left ventricle to right ventricle during systole. It produces a systolic murmur. Septal defect is a rare disorder. 4. Coarctation of Aorta It is a congenital disorder, characterized by the narrowing of a part of systemic aorta . A loud murmur is produced during systole and it is heard in the earlier part of diastole also. 70

71. DIASTOLIC MURMUR „ Diastolic murmur is the murmur that is produced during diastole . Stenosis of Atrioventricular Valves When the atrioventricular valves become narrow, the turbulence of blood flow occurs during diastole. It is a weak sound with low frequency. Sometimes, murmur due to mitral stenosis cannot be heard by stethoscope, due to low frequency. But it can be felt as a mild thrill over mitral area of the chest. 71

72. Incompetence of Semilunar Valves Murmur is produced during the regurgitation of blood from aorta into the ventricle, through incompetent semilunar valve during diastole. It is like a blowing sound with low frequency. 72

73. CONTINUOUS MURMUR Continuous murmur is the murmur that is heard in conditions such as patent ductus arteriosus . Patent Ductus Arteriosus 73 A continuous murmur is heard in this condition. However, intensity of the sound is more during systole and less during diastole. Because of this, it is also called machinery murmur. It is a harsh blowing sound and is heard best in the pulmonary area. The murmur is heard 1 year after birth.

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