Pathology of heart

1. Pathology of
the heart

2. Congestive Heart Failure (CHF)
• CHF is a heart that fails when it is unable to eject
blood delivered to it by the venous system. The
inferior vena cava (IVC) empties blood into the right
atrium (RA), and the pulmonary vein empties blood
into the left atrium (LA)

3. Pump failure
• Divided into right- and left-sided failure

4. Causes of left-sided failure
• Ischemia
• Hypertension
• Dilated cardiomyopathy
• MI
• Restrictive cardiomyopathy

5. Pulmonary congestion
• Pulmonary edema with dyspnea, PND, orthopnea,
crackles
• Heart-failure cells

7. Decreased forward perfusion
•Activation of renin-angiotensin system
•Mainstay of treatment is ACE inhibitor

8. Right-sided heart failure is most commonly
due to left failure
• Other important causes include left-to-right shunt and
chronic lung disease (cor pulmonale)

9. Clinical features are due to congestion
• JVD (jugular venous distention)
• Painful HSM (hepatosplenomegaly), may lead to
cardiac cirrhosis
• Dependent pitting edema

10. Ischemic heart
disease

11. Group of syndromes related to myocardial
ischemia
•Usually due to atherosclerosis of coronary artery

12. Stable angina
•Chest pain that arises with exertion or emotional
stress
•Due to atherosclerosis of coronary arteries with
˃ 70% stenosis
•Represents reversible injury to myocytes

13. Presentation
•Chest pain (˂20 minutes) that radiates to left
arm or jaw
•Diaphoresis
•Shortness of breath

14. Stable angina
•EKG shows ST-segment depression
(subendocardial ischemia)
•Relived by rest or nitroglycerin

15. Unstable angina
•Chest pain that occurs at rest
•Due to rupture of atherosclerotic plaque
with thrombosis and incomplete occlusion
of a coronary artery
•Represents reversible injury to myocytes

16. Unstable angina
•EKG shows ST-segment depression
•Relieved by NG
•High risk of progression to MI

18. Prinzmetal angina
•Due to coronary artery vasospasm
•Leads to episodic chest pain unrelated to
exertion

19. Prinzmetal angina
•Represents reversible injury to myocytes
•EKG shows ST-segment elevation due to
transmural ischemia
•Relieved by NG or calcium channel blockers

20. Myocardial infarction
• Necrosis of cardiac myocytes
• Due to rupture of atherosclerotic plaque with
thrombosis and complete occlusion of coronary artery
• Other causes include coronary artery vasospasm,
emboli and vasculitis

23. Clinical features
• Severe, crushing chest pain (˃ 20 minutes) that
radiates to left arm or jaw
• Diaphoresis
• Dyspnea
• Symptoms not relieved by NG

24. Infarction usually involves LV
•RV and both atria are generally spared

26. Initial phase
•Subendocardial necrosis involving ˂ 50% of
myocardial thickness
•EKG shows ST-segment depression

28. Laboratory tests detect elevated
cardiac enzymes

29. Troponin I is most sensitive and
specific marker
•Rises 2-4 hours after infarction
•Peaks at 24 hours
•Returns to normal by 7-10 days

30. CK-MB is useful for detecting
reinfarction days after MI
•Rises 4-6 hours after infarction
•Peaks at 24 hours
•Returns to normal by 72 hours

31. Treatment
•ASA/Heparin
•Supplemental O2
•Nitrates
•Β-blocker
•ACE inhibitor

43. Sudden cardiac death
•Unexpected death due to cardiac disease
•Occurs without symptoms or ˂ 1 hour after
symptoms arise
•Usually due to fatal ventricular arrhythmia

44. Most common etiology is acute
ischemia
•90 % of patients have preexisting severe
atherosclerosis
•Less common causes include mitral valve
prolapse, cardiomyopathy and cocaine
abuse

45. Chronic Ischemic Heart Disease
•Poor myocardial function
•Due to chronic ischemic damage (with or
without infarction)
•Progresses to CHF

46. Congenital
defects

47. Arise during embryogenesis
•Usually weeks 3-8
•Seen in 1% live births
•Most defects are sporadic
•Often result in shunting between left and right
circulations

48. VSD (ventricular septal defect)
• Defect in the septum that divides right and left
ventricles
• Most common congenital heart defect
• Associated with fetal alcohol syndrome

50. Result in left-to-right shunt
•Size of defect determines extent of shunting
and age presentation
•Small defects are often asymptomatic
•Large defects can lead to Eisenmenger
syndrome

51. Treatment
•Surgical closure
•Small defects may close spontaneously

52. ASD (atrial septal defect)
•Defect in septum that divides left and right atria
•Most common type is ostium secundum
•Ostium primum type is associated with Down
syndrome

53. Result in left-to-right shunt
•Split S2 on auscultation
•Paradoxical emboli are important
complication

55. PDA (patent ductus arteriosus)
•Failure of ductus arteriosus to close
•Associated with congenital rubella

57. Result in left-to-right shunt
between aorta and PA
•Asymptomatic at birth with holosystolic
“machine-like” murmur
•Eisenmenger syndrome results in lower
extremity cyanosis

58. Treatment
•Indomethacin
•Decreases PGE, resulting in PDA closure

59. Tetralogy of Fallot
•Stenosis of RV outflow tract
•Right ventricular hypertrophy
•VSD
•Aorta that overrides the VSD

61. Right-to-left shunt
•Leads to early cyanosis
•Degree of stenosis determines extent of
shunting and cyanosis

63. Transposition of Great vessels
•Pulmonary artery arises from LV and aorta
arises from RV
•Associated with maternal diabetes

65. Presents with early cyanosis
•Pulmonary and systemic circuits do not mix
•Creation of shunt after birth is required for
survival
•PGE can be administered to maintain PDA until
definitive surgical repair is performed

66. Truncus Arteriosus
•Single large vessel arising from both
ventricles
•Truncus fails to divide

68. Presents with early cyanosis
•Deoxygenated blood from RV mixes with
oxygenated blood from LV before
pulmonary and aortic circulations separate

69. Valvular
disorders

71. Acute Rheumatic Fever
•Systemic complication of pharyngitis due to
group A β-hemolytic streptococci
•Affects children 2-3 weeks after strep throat
•Caused by molecular mimicry; bacterial M
protein resembles human tissues

72. Diagnosis based on Jones criteria
•Evidence of a prior group A β-hemolytic strep
infection (ASO or anti-DNase B titer)
•Minor criteria (fever and elevated ESR)
•Major criteria

77. Acute attack resolves but may
progress to chronic disease
•Repeat exposure to group A β-hemolytic
streptococci results in relapse of acute
phase
•Increases the risk for chronic rheumatic
valvular disease

78. Chronic Rheumatic Valve Disease
•Valve scarring that results from rheumatic fever

79. Results in stenosis
•Almost always involves mitral valve; leads to
thickening of chordae tendineae and cusps
•Occasionally involves aortic valve; leads to fusion
of commissures
•Other valves less commonly involved
•Complication is endocarditis

81. Aortic Stenosis
•Narrowing of aortic valve orifice

82. Usually due to fibrosis and
calcification from “wear and tear”
•Presents in late adulthood (˃ 60 years)
•Bicuspid aortic valve increases risk and
hastens disease onset

84. May also arise from chronic
rheumatic valve disease
•Coexisting mitral stenosis and fusion of aortic
valve commissures distinguish rheumatic disease
from “wear and tear”

85. Compensation leads to
•Prolonged asymptomatic stage
•Systolic ejection click followed by a crescendo-
decrescendo murmur

86. Complications
•Concentric left ventricular hypertrophy
•Angina and syncope with exercise
•Microangiopathic hemolytic anemia

87. Treatment
•Valve replacement after the onset of
complications

88. Aortic Regurgitation
•Backflow of blood from aorta into LV during
distole
•Arises due to aortic root dilation (e.g., syphilitic
aneurysm) or valve damage (e.g., IE)

90. Clinical features
•Early, blowing, diastolic murmur
•Bounding pulses, pulsating nail bed, and head
bobbing (hyperdynamic circulation)
•LV dilation and eccentric hypertrophy
•Treatment is valve replacement when LV
dysfunction develops

91. Mitral Valve Prolapse
•Ballooning of mitral valve into left atrium during
systole
•Due to myxoid degeneration in valve making it
floppy
•Etiology is unknown; may be seen in Marfan and
EDS

93. Clinical features
•Mid-systolic click followed by regurgitation
murmur; usually asymptomatic
•Complications (IE, arrhythmia, severe mitral
regurgitation) are rare
•Treatment is valve replacement

95. Mitral Regurgitation
•Reflux of blood from LV into LA during systole
•Usually arises as a complication of MVP
•Other causes include LV dilation, infective
endocarditis, acute rheumatic heart disease,
papillary muscle rupture after MI

97. Clinical features
•Holosystolic “blowing” murmur
•Louder with squatting and expiration
•Results in volume overload and left-sided heart
failure

98. Mitral stenosis
•Narrowing if the mitral valve orifice
•Usually due to chronic rheumatic valve
disease

99. Clinical features
•Opening snap followed by diastolic rumble

100. Volume overload leads to dilatation of
the LA
•Pulmonary congestion
•Pulmonary HTN
•Atrial fibrillation

104. Endocarditis

105. Basic principles
•Inflammation of endocardium that lines the
surface of cardiac valves
•Usually due to bacterial infection

106. Strep viridans
•Most common overall cause
•Low-virulence organism; infects previously
damaged values
•Results in small vegetations that do not destroy
valve

107. Pathogenesis
•Damaged endocardial surface develops
thrombotic vegetations (platelets and fibrin)
•Transient bacteremia leads to trapping of
bacteria in vegetations

108. Staph aureus
• Most common cause in IV drug-abuse
• High-virulence organism; infects normal valves
(tricuspid)
• Results in large vegetations that destroy valve (acute
endocarditis)

110. Staph epidermidis
•Endocarditis of prosthetic valves

111. Strep bovis
•Endocarditis in patients with underlying
colorectal carcinoma

112. HACEK organisms
•Endocarditis with negative blood cultures
•Includes Hemophilus, Actinobacillus,
Cardiobacterium, Eikenella, Kingella

113. Clinical features
•Fever
•Murmur
•Janeway lesions
•Osler nodes
•Anemia of chronic disease

114. Laboratory features
•Positive blood cultures
•Anemia of chronic disease
•TEE is useful for detecting lesions on valves

115. Nonbacterial thrombotic
endocarditis
•Sterile vegetations that arise with
hypercoagulable state or underlying
adenocarcinoma
•Vegetations arise on mitral valve along lines of
closure and result in regurgitation

116. Libman-Sacks Endocarditis
•Sterile vegetations associated with SLE
•Vegetations present on surface and
undersurface (both sides) of mitral valve
•Result in mitral regurgitation

117. Cardiomyopathy

118. Basic principles
•Myocardial diseases resulting in cardiac
dysfunction

119. Dilated Cardiomyopathy
•Dilation of all 4 chambers of the heart
•Most common form of cardiomyopathy

121. Results in systolic dysfunction leading
to biventricular CHF
•Complications include mitral and tricuspid valve
regurgitation and arrhythmia

122. Most commonly idiopathic, other
causes include
•Genetic mutation
•Myocarditis
•Alcohol abuse
•Drugs
•Pregnancy

124. Treatment
•Transplant

125. Hypertrophic Cardiomyopathy
•Massive hypertrophy of the LV
•Due to genetic mutations in sarcomere proteins
(most commonly AD)

126. Clinical features
•Decreased cardiac output
•Sudden death due to ventricular arrhythmias;
common cause of sudden death in young
athletes
•Syncope with exercise

127. Biopsy
•Myofiber hypertrophy with disarray

129. Restrictive Cardiomyopathy
•Decreased compliance of ventricular
endomyocardium
•Restricts filling during diastole

130. Causes
•Amyloidosis
•Sarcoidosis
•Hemochromatosis
•Endocardial fibroelastosis (children)
•Loeffler syndrome

131. Presents as CHF
•Classic finding is low-voltage EKG
•Diminished QRS amplitudes

132. Cardiac tumors

133. Myxoma
•Benign mesenchymal proliferation with a
gelatinous appearance
•Abundant ground substance on histology
•Most common primary cardiac tumor adults

134. Rhabdomyoma
•Benign hamartoma of cardiac muscle
•Most common primary cardiac tumor in
children; associated with tuberous sclerosis
•Usually arises in ventricle

135. Metastasis
•More common than primary tumors
•Common metastases to the heart include breast
and lung carcinoma, melanoma, lymphoma
•Most commonly involves pericardium, resulting
in a pericardial effusion