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Disorders of Cardiac Function

Disorders of Cardiac Function. Cardiac Pathology Outline. Blood Vessels Heart I Heart Failure Congenital Heart Disease Ischemic Heart Disease. Ischemic Heart Disease. Myocardial perfusion can ’ t meet demand

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Disorders of Cardiac Function

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  1. Disorders of Cardiac Function

  2. Cardiac Pathology Outline • Blood Vessels • Heart I • Heart Failure • Congenital Heart Disease • Ischemic Heart Disease

  3. Ischemic Heart Disease • Myocardial perfusion can’t meet demand • Usually caused by decreased coronary artery blood flow (“coronary artery disease”) • Four syndromes: • angina pectoris • acute MI • chronic IHD • sudden cardiac death

  4. Angina Pectoris • Intermittent chest pain caused by transient, reversible ischemia • Typical (stable) angina • pain on exertion • fixed narrowing of coronary artery • Prinzmetal (variant) angina • pain at rest • coronary artery spasm of unknown etiology • Unstable (pre-infarction) angina • increasing pain with less exertion • plaque disruption and thrombosis

  5. Myocardial Infarction • Necrosis of heart muscle caused by ischemia • 1.5 million people get MIs each year • Most due to acute coronary artery thrombosis • sudden plaque disruption • platelets adhere • coagulation cascade activated • thrombus occludes lumen within minutes • irreversible injury/cell death in 20-40 minutes • Prompt reperfusion can salvage myocardium

  6. Manifestations of ST-Segment Elevation Acute Myocardial Infarction • Abrupt onset • Severe and crushing pain, usually substernal, radiating to the left arm, neck, or jaw • Gastrointestinal complaints (nausea and vomiting) • Complaints of fatigue and weakness • Tachycardia, anxiety, restlessness, feelings of doom • Pale, cool, and moist skin

  7. ST Segment • Abnormalities of the ST segment and the T wave represent abnormalities of ventricular repolarization.

  8. Factors Determining the Extent of an Infarct • Location and extent of occlusion • Amount of heart tissue supplied by the vessel • Duration of the occlusion • Metabolic needs of the affected tissue • Extent of collateral circulation • Heart rate, blood pressure, and cardiac rhythm

  9. Morphologic Changes in Myocardial Infarction

  10. Acute Myocardial Infarction

  11. MI: day 1, day 3, day 7

  12. Myocardial Infarction • Clinical features • Severe, crushing chest pain ± radiation • Not relieved by nitroglycerin, rest • Sweating, nausea, dyspnea • Sometimes no symptoms • Laboratory evaluation • Troponins increase within 2-4 hours, remain elevated for a week. • CK-MB increases within 2-4 hours, returns to normal within 72 hours.

  13. Myocardial Infarction • Complications • contractile dysfunction • arrhythmias • rupture • chronic progressive heart failure • Prognosis • depends on remaining function and perfusion • overall 1 year mortality: 30% • 3-4% mortality per year thereafter

  14. Rupture of papillary muscle after MI

  15. Cardiac Pathology Outline • Blood Vessels • Heart I • Heart Failure • Congenital Heart Disease • Ischemic Heart Disease • Hypertensive Heart Disease

  16. Hypertensive Heart Disease • Can affect either L or R ventricle • Corpulmonale is RV enlargement due to pulmonary hypertension caused by primary lung disorders • Result: myocyte hypertrophy • Reasons for heart failure in hypertension are poorly understood

  17. Left ventricular hypertrophy (L) and cor pulmonale (R)

  18. Cardiac Pathology Outline • Blood Vessels • Heart I • Heart II

  19. Cardiac Pathology Outline • Blood Vessels • Heart I • Heart Failure • Congenital Heart Disease • Ischemic Heart Disease • Hypertensive Heart Disease

  20. Cardiac Pathology Outline • Blood Vessels • Heart I • Heart II • Valvular Heart Disease • Cardiomyopathies • Pericardial Disease • Tumors

  21. Cardiac Pathology Outline • Blood Vessels • Heart I • Heart II • Valvular Heart Disease

  22. Valvular Heart Disease • Stenosis and/or insufficiency • Stenosis: failure to open • Insufficiency: failure to close • Murmurs • Outcome depends on severity and speed of development

  23. Calcific Aortic Stenosis • Part of aging process • Can occur on normal or congenitally bicuspid valves • Results in increased LV pressure, LV hypertrophy, and relative ischemia • Angina, CHF, or fainting

  24. Calcific aortic stenosis: normal (L) and bicuspid (R) valves

  25. Mitral Valve Prolapse • Common (5% of adults in US, F>M) • Ballooning of mitral leaflets • Myxoid/mucoid change within leaflet • Pathogenesis unknown • Most patients asymptomatic

  26. Mitral valve prolapse

  27. Rheumatic Valvular Disease • Rheumatic fever: systemic inflammatory disease occurring a few weeks after strep throat • Valves (esp. mitral) become scarred • Consequence: stenosis (± regurgitation)

  28. Rheumatic Fever • Body makes antibody to strep bug that cross-reacts with antigens in heart and joints • 2-3 weeks after strep throat, patient gets: • migratory polyarthritis • pericardial friction rub, arrhythmias • Chronic disease can reappear decades later • mitral stenosis, left atrial enlargement, thrombi • increased risk of infective endocarditis • Long term prognosis variable

  29. Strep throat Antibody production Antibody cross-reaction with heart vegetations Aschoff body pericarditis

  30. Mitral stenosis with commissural fusion

  31. Infective Endocarditis • Microbial invasion of heart valves, endocardium • Acute endocarditis • highly virulent bug attacks normal valve • half of patients dead within days to weeks • Subacuteendocarditis • low virulence bug colonizes abnormal valve • slow onset, long course, most recover • Symptoms: fever, flu-like symptoms • Complications: septicemia, arrhythmias, renal failure, systemic emboli

  32. Invasion of the heart valves and endocardium by a microbial agent Formation of bulky, friable vegetations and destruction of underlying cardiac tissues Systemic manifestations Streptocococci Enterococci Haemophilussp. Actinobacillusactinomycetemcomitans Cardiobacteriumhominis Eikenellacorrodens Kingellakingae Gram-negative bacilli Fungi Infective Endocarditis

  33. Infective endocarditis: splinter hemorrhage of nail bed

  34. Cardiac Pathology Outline • Blood Vessels • Heart I • Heart II • Valvular Heart Disease • Cardiomyopathies

  35. Myocardial Diseases • Myocarditis • Inflammation of the heart muscle and conduction system without evidence of myocardial infarction • Primary cardiomyopathies • Heart muscle diseases of unknown origin • Secondary cardiomyopathies • Conditions in which the cardiac abnormality results from another cardiovascular disease, such as myocardial infarction

  36. Cardiomyopathies • Diverse group of disorders in which there is intrinsic myocardial dysfunction • Lots of causes; some idiopathic • Three groups • dilated cardiomyopathy • hypertrophic cardiomyopathy • restrictive cardiomyopathy

  37. Dilated Cardiomyopathy • Heart dilates, enlarges, and can’t contract well • Causes • viral • alcohol/toxin • genetic abnormalities • peripartum • Slowly progressing CHF • 70% of patients dead within 5 years

  38. Dilated (L) and hypertrophic (R) cardiomyopathy

  39. Sarcomere of cardiac muscle

  40. Restrictive Cardiomyopathy • Heart wall is stiff; can’t fill during diastole • Cause: Idiopathic or secondary to systemic disease (amyloidosis, hemochromatosis, sarcoidosis) • Symptoms: shortness of breath, peripheral edema • Treatment: not often helpful • 70% of patients dead within 5 years

  41. Hypertrophic Cardiomyopathy • Massively hypertrophied L ventricle can’t fill • Cause: mutation in a sarcomereprotein gene • Symptoms: atrial fibrillation, CHF, arrhythmia, sudden death • Treatment: drugs to promote ventricular relaxation or surgical excision of part of septum • Prognosis: about 4% of patients die each year

  42. Treatment of Cardiomyopathy • Treatment depends on the type • Medication • Implanted pacemakers • Defribillators • Ventricular assist devices • Ablation • The goal of treatment is often symptom relief, and some patients may eventually require a heart transplant.

  43. Cardiac Pathology Outline • Blood Vessels • Heart I • Heart II • Valvular Heart Disease • Cardiomyopathies • Pericardial Disease

  44. Pericardial Disease • Pericarditis • secondary (MI, radiation, pneumonia) or primary (infectious) • atypical chest pain • dangers: tamponade, chronic fibrosis • Pericardial effusion • serous (CHF), serosanguinous (aortic dissection), chylous (lymphatic obstruction) • outcome depends on stretchiness of pericardial sac • slow = asymptomatic; sudden = catastrophic

  45. Acute pericarditis

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