Chapter 19 Disorders of Cardiac Function

1. Essentials of Pathophysiology Chapter 19Disorders of Cardiac Function

2. Pericarditis represents an inflammatory process of the myocardium. All types of angina represent an acute myocardial infarction, also known as a heart attack. The heart extracts and uses 60% to 80% of the oxygen in blood flowing through the coronary arteries. Atherosclerosis is by far the most common cause of coronary heart disease. Stable atherosclerotic plaques tend to rupture more than unstable atherosclerotic plaques and lead to acute coronary syndromes, ranging from unstable angina to ST-segment elevation myocardial infarction. PRE-LECTURE QUIZ F F T T F

3.  Cardiac __________ is a life-threatening, slow or rapid compression of the heart due to the accumulation of fluid, pus, or blood in the pericardial sac. Rheumatic heart disease, a disorder that follows a group A _____________ throat infection, is of great concern because of the potential effects of chronic valvular disorders that produce permanent cardiac dysfunction and sometimes fatal heart failure years later. __________ refers to a narrowing of the valve orifice and failure of the valve leaflets to close properly.  Creatinekinase, myoglobin, and troponin are known as serum cardiac __________ and are useful for acute myocardial infarction determination and classification. Coronary heart disease is a disorder of impaired __________ blood flow, usually caused by atherosclerosis. PRE-LECTURE QUIZ corornary Markers Stenosis Streptococcal Tamponade

4. Pericardial disorders • Coronary heart disease • Myocardial diseases • These disorders can cause symptoms of both right- and left-sided heart failure Disorders That Affect the Whole Heart

5. The Pericardium Surrounds the Heart

6. Inflammation of the pericardium causes: • Pain • Exudate • Serous  pericardial effusion • Cardiac tamponade: rapid accumulation of exudate compresses the heart • Fibrous  friction rub; adhesions • ECG changes Pericarditis

7. Inflammation of the pericardium may restrict the heart’s movement due to: • Serous exudate filling the pericardial cavity (pericardial effusion) • Fibrous scar tissue making the pericardium stick to the heart (constrictive pericarditis) Pericarditis (cont.)

8. ConsequencesofPericardialEffusion fluid in pericardial cavity restricts heart expansion right ventricle left ventricle cannot accept cannot accept enough blood enough blood decreased increased venous cardiac pressure; jugular output distension decreased blood pressure and shock

9. What is the immediate treatment for severe cardiac tamponade? • Oxygen • Cardiac drugs • Surgery • Pericardiocentesis (removal of fluid from the sac with a needle) Question

10. Inflammation of the pericardium causes: • Pain • Exudate • Serous  pericardial effusion • Cardiac tamponade: rapid accumulation of exudate compresses the heart • Fibrous  friction rub; adhesions • ECG changes Pericarditis

11. Inflammation of the pericardium may restrict the heart’s movement due to: • Serous exudate filling the pericardial cavity (pericardial effusion) • Fibrous scar tissue making the pericardium stick to the heart (constrictive pericarditis) Pericarditis (cont.)

12. Consequences ofPericardial Effusion fluid in pericardial cavity restricts heart expansion right ventricle left ventricle cannot accept cannot accept enough blood enough blood decreased increased venous cardiac pressure; jugular output distension decreased blood pressure and shock

13. What is the immediate treatment for severe cardiac tamponade? • Oxygen • Cardiac drugs • Surgery • Pericardiocentesis Question (removal of fluid from the sac with a needle)

14. Pericardiocentesis (removal of fluid from the sac with a needle) Rationale:In severe cardiac tamponade, there is so much fluid in the pericardial sac compressing the heart that its function declines rapidly. The fluid must be removed quickly by inserting a needle into the pericardial space and aspirating the accumulated fluid. Answer

15. On inhaling, the rightventricle fills with extra blood When the right ventricle is overfilled, the left ventricle is compressed and cannot accept much blood. Because the heart cannot fully expand On the next heartbeat, the left ventricle does not send out much blood: systolic BP drops Pulsus Paradoxus

16. Atherosclerosis blocks coronary arteries • Ischemia may cause: • Angina • Heart attack • Cardiac arrhythmias • Conduction deficits • Heart failure • Sudden death Coronary Heart Disease

17. Plaque/Thrombus Formation

19. Imbalance in blood supply and the heart’s demands for oxygen • Less blood • Atherosclerosis • Vasospasm • Thrombosis • Higher oxygen demand • Stress • Exercise • Cold Chronic Ischemic Heart Disease

21. Stable angina • Pain when heart’s oxygen demand increases • Variant angina • Pain when coronary arteries spasm • Silent myocardial ischemia • Myocardial ischemia without pain Kinds of Angina

22. ECG changes • T-wave inversion • ST-segment depression or elevation • Abnormal Q wave • Serum cardiac markers • Proteins released from necrotic heart cells • Myoglobin, creatine kinase, troponin Acute Coronary Syndromes

23. Tell whether the following statement is true or false. Chronic ischemic heart disease is more likely to result in stable angina than acute coronary syndromes. Question

24. True Rationale:Ischemic heart disease is characterized by stable angina, which is associated with plaques that are fixed obstructions. Unstable angina is characterized by plaques with platelets stuck to them (these are likely to form a thrombus)—they cause a range of acute coronary syndromes. Answer

25. Chest pain • Severe, crushing, constrictive, OR like heartburn • Sympathetic nervous system response • GI distress, nausea, vomiting • Tachycardia and vasoconstriction • Anxiety, restlessness, feeling of impending doom • Hypotension and shock • Weakness in arms and legs Acute Myocardial Infarction

26. An Acute MI (AMI) Leaves Behind an Area of Yellow Necrosis

27. Heart failure Cardiogenic shock Pericarditis Thromboemboli Rupture of the heart Ventricular aneurysms Complications of AMI

28. Malfunctioning heart muscle can cause heart failure if: • Ventricles are unusually thick so there is not a normal amount of room for blood inside them (hypertrophic cardiomyopathy) • Ventricles are too stiff to stretch (restrictive cardiomyopathy) • Ventricles are too weak to pump out the blood that is in them (MI, myocarditis, dilated cardiomyopathy) Malfunctioning Heart Muscle

29. Myocarditis • Cardiomyopathies • Dilated cardiomyopathies • Hypertrophic cardiomyopathies • Restrictive cardiomyopathies • Peripartum cardiomyopathy Myocardial Disorders

30. Defects in their contractile proteins make cells too weak They hypertrophy to do the same amount of work as normal cells Need more oxygen and perform less efficiently, so the person is prone to heart failure and may suffer sudden death during exertion Hypertrophic Cardiomyopathy

31. Which type of cardiomyopathy is characterized by weakened ventricles? • Dilated cardiomyopathy • Hypertrophic cardiomyopathy • Restrictive cardiomyopathy • Peripartum cardiomyopathy Question

32. Dilated cardiomyopathy Rationale:In dilated cardiomyopathy, the ventricles are too weak to pump blood, resulting in a diminished cardiac output (CO). The other types listed are caused by thick ventricles, stiff ventricles, or LV dysfunction in late pregnancy or postpartum, respectively. Answer

33. By interfering with normal blood flow, these often cause the signs and symptoms of left- or right-sided heart failure Valvular Disorders and Heart Defects body left right heart heart lungs

34. The endocardial structures lining the heart can cause heart failure • If the AV valves leading into the ventricles do not work (mitral or tricuspid problems) • If the semilunar valves leading out of the ventricles do not work (aortic or pulmonary problems) The Endocardial Structures

35. Discussion: Arrange these steps in the proper order: – Ventricles relax – First heart sound – Start Systole – Semilunar valves open – End Diastole – AV valves close – AV valves open – Semilunar valves close – Ventricles contract – Second heart sound Cardiac Cycle 4 6 5 1 10 3 9 7 2 8

36. Each of the four valves can be defective • Stenosis: valve will not open all the way; it is harder to force blood through it • Regurgitation: valve will not close all the way; it leaks when it should be closed • Also called valvular insufficiency Valve Defects

37. Tell whether the following statement is true or false. Mitral valve regurgitation results in a diminished stroke volume. Question

38. True Rationale:If the mitral valve does not close as it should, a portion of the stroke volume (amount of blood ejected by the ventricle/beat) leaks back into the left atrium, decreasing the amount of blood that is ejected during that beat (SV). Answer

39. Defects in which valves might cause: • Severe dependent edema? • Paroxysmal nocturnal dyspnea? • Congested liver? • Distended jugular veins? • Productive cough with frothy sputum? Discussion

40. The blood going through the valve makes a noise • These are called heart murmurs • You can identify them by: • Where they are—which valve are they near? • How they sound—high- or low-pitched? • When they happen—systole or diastole? Identifying Defective Valves

41. If a valve is stenotic, you will hear a murmur of blood shooting through the narrow opening when the valve is open • If a valve is regurgitant, you will hear a murmur of blood leaking back through when the valve should be closed When Will You Hear Murmurs?

42. Mitral valve disorders • Mitral valve stenosis • Mitral valve regurgitation • Mitral valve prolapse • Aortic valve disorders • Aortic valve stenosis • Aortic valve regurgitation Left-sided Valvular Disorders

43. Valvular Disorders • Mitral Regurgitation • Part of SV goes back into the LA • Heart has to work harder to meet body needs • LV hypertrophy • Aortic Valve Stenosis • Aortic valve is constricted • Difficult to pump blood from the LV • LV hypertrophy • Mitral Stenosis • Incomplete LV filling • Lower CO • Aortic Regurgitation • Blood flows backward into the LV from the Aorta • LV Dilatation

44. Atrial septal defects Ventricular septal defects Endocardial cushion defects Patent ductus arteriosus Pulmonary stenosis Tetralogy of Fallot Transposition of the great vessels Coarctation of the aorta Congenital Heart Defects

45. A shunt is an opening or connection that lets blood move from one side of the circulation to the other Most shunts occur in the heart and move blood either from the left to the right or from the right to the left Because the left side is stronger, blood is usually pushed from the left to the right side Shunts

46. Shunts are normal before birth • Foramen ovale • Lets blood go from the right atrium to the left atrium to bypass the lungs • Ductus arteriosus • Lets blood go from the pulmonary trunk to the aorta to bypass the lungs • Ductus venosus • Lets blood go from the visceral veins to the vena cava, bypassing the liver Shunts (cont.)

47. Left-to-right Shunt Less blood goes to body body left right Blood moves from left to right heart heart More blood goes to lungs lungs

48. Right-to-left Shunt Deoxygenated blood goes to body body left Blood moves from right to left right heart heart Less blood goes to lungs lungs

49. Show how the diagram would look for: • Patent ductus arteriosus Discussion body left right heart heart lungs

50. Show how the diagram would look for: • Transposition of the great vessels Discussion body left right heart heart lungs