1/26/99
Pathology II
Chronic rheumatic heart disease
-irreversible valve
deformity-scarring effects
-most common cause of mitral
stenosis
-more
common in females (reason unknown)
-"fish-mouth"
deformity of valve orifice
-left
atrial hypertrophy
-mural
thrombi
-aortic valvulitis-stenonsis
-more
common in males
-pressure
load on LV-hypertrophy
-leads
to LVF
Fig 11-14
Clinical Features
-10 days to 6 weeks after group A
strep pharyngitis
-peak incidence - 5-15 yrs/o
Calcific Aortic Stenosis
-degenerative changes due to aging
-degenerative calcific aortic
stenosis (dcas)-most common cause of isolated aortic stenosis in US
-may occur on normal valve or
congenitally bicuspid or unicuspid valve
-usually asympotmatic and detected
incidentally on chest x-ray
fig 11-15
Clinical Findings
--harsch crescendo-decrescendo
systolic murmur
-LV hypertrophy develops
-angina - increase myocardial need
for oxygen
-syncope-decrease perfusion of the
brain
-CHF-later stages
-untreated-death in 3-4 years after
symptom onset from CHF or a lethal arrhythmia
-surgical valve replacement is
needed
Mitral Valve Prolapse
-most common cause of isolated
mitral regurgitation
-occurs in about 5% of general adult population
-more cases in women-ages 20-40 yrs
-loose ground substance in valve
leaflets and chordae
-valve is "floppy" and
incompetence during systole
-may be isolated, non-familial
abnormality
-Marfan's syndrome or other
connective tissue disorder
Morphology
-valve cusps (posterior)
Clinical Features
Nonbacterial Thrombotic Endocarditis
(nbte)
-AKA marantic Endocarditis-due to
its appearance in cachectic patients
-sterile vegetations on previously
normal valves
-not well understood
-subtle
endothelial abnormalities
-hypercoagulable
states
-malignancies (adenocarcinomas) in
50% of patients who possess other hypercoagulable features-deep vein thrombosis
-nbte lesions my heal-leaving
fibrous strands called Lambi's excrescence
fig 11-17a&b
Ineffective Endocarditis
-infection of cardiac valves or
mural surface of endocardium form in a vegetation (adherent mass of thrombotic
debris and organisms)
-classic forms
1. acute Endocarditis-caused by highly virulent
organism like Staphylococcus aurous can affect normal valves
2. subacute endocarditis-caused by less
virulent organism-alpha hemolytic streptococci-previously abnormal valves
fig 11-18
Etiology
-bacteremia-implanting of organism
on endocardial surface
1.
b. chronic valvular disease
1)
chronic rheumatic heart disease
2)
DCAS
3)
mitral valve prolapse
2.
Prosthetic heart valves
-account
for 10-20% of infective endocarditis
3.
intravenous drug users--usually normal valves
Causative Organisms
--alpha hemolytic strep
(50-60%)-endocarditis of native, previously damaged valves
-S. aeures
Morphology
-hallmark
Acute Endocarditis
-vegetations
may form bulky lesions and obstruct valves
-may
rapidly destroy valves, more into adjacent myocardium and form ring abscesses
-systemic
emboli-site of infarct may develop abscesses
Subacute
-firmer
lesions, less valvular destruction
-less
erosion of valve
-systemic
emboli-usually do not abscess
Clinical
-gradual or explosive
-low-grade fever, malaise, weight
loss
-cardiac murmurs are present
-spleen is often enlarged
-systemic emboli are common
-neurologic
defects
-retinal
abnormalities
-necrosis
of the digits
-petcechiae
in skin or mucosa
-splinter
hemorrhages
-renal
lesions
Primary Myocardial Diseases
-intrinsic myocardial disease-less
frequent cause of disease
-myocarditis and cardiomyopathies
most important
Myocarditis
-inflammation of myocytes
-viral infections-Coxackieviruses A
and B, CMV, HIV, less common causes
-Parasites-Chagas's disease
(Trypanosoma cruzi)
-bacterial: lyme disease
-cardiac allograft rejection
Cardiomyopathies
-heart muscle disease resulting from
a primary abnormality in the myocardium
-3 Major Groups
1. dilated
-progressive cardiac hypertrophy,
dilatation, and contractile (systolic) dysfxn
-viral
infection, alcohol abuse-toxic insult
-peripartum
cardiomyopathy-occurs late in pregnancy or post partum. Poorly understood
-idiopathic
dilated cardiomyopathy--most cases
Morphology
-enlarged, flabby heart >900g
-combo of dilation and hypertrophy
-mural thrombi due to blood stasis
Clinical
-ineffective feeble contractions
-leading to progressive congestive heart failure
-Tx: transplant
Hypertrophic Cardiomyopathy
-asymmetric
septal hypertrophy
-idiopathic hypertrophic subaortic
stenosis
-characterized by myocardial
hypertrophy, abnormal diastolic filling, intermittent ventricular outflow
obstruction
-powerfully contracting
heart-pronounced LVH
-50% of cases-inherited autosomal
dominant-mutations in gene coding for heavy chain beta-myosin
-associated w/other hereditary
disorders-neurofibromatosis
Clinical
-basic abnormality-inability to fill
the hypertrophic LV
-LV ejection is forceful, but
ineffective due to decreased diastolic filling
-angina is common
-increased incidence of ventricular
arrhythmia's, sudden death, and infective endocarditis
-common cause of sudden unexplained
death in young athletes
Restrictive Cardiomyopathy
-primary decrease in ventricular
compliance, resulting in impaired ventricular filling during diastole
-stiff, inelastic ventricle-very
difficult to fill
-caused by anything that can reduce
myocardial compliance
endomyocardial fibrosis-world
wide-10% of childhood heart disease
-Loffler'syndrome-eosinophilic
endomyocardial fibrosis-rare, tropical form
-other causes-cardiac amyloidosis,
hemochromatosis
Congenital Heart Disease
-incidence about in 8 in 1000 live
births
-genetic factors-trisomies 13, 15,
18, 21, and Turner's syndrome
-environmental factors-congenital
rubella infection
-unknown causes in 90% of cases
L to R Shunts (cyanosis is a late
feature)
-atrial septal defects (asd's)
-ventricular septal defects (vsd's)
-patent ductus arteriosus (pda)
-normal closure--ligamentum
arteriosum
Atrial Septal Defects
-incidence: 10% of congenital heart defects
-3:2 males:females
-Tx: surgical closure
-3 types of defects;
1. ostium secundum ASD-most common 40%
Ventricular Septal Defects
-the most common congenital heart
defect
-incidence: 20% of congenital heart lesions-5% may
coexist w/other lesions
-variable effects-depends on
size-ranges from asymptomatic to congestive heart failure
-Tx: ranges from spontaneous closure to surgical closure
Patent Ductus Arteriousus
-incidence 10%
-abnormal persistent fetal
connection b/w L pulmonary artery and descending aorta
-oxygenated blood flows
LV--pulmonary aa--lungs--LA (volume over load)
R to L shunts (early appearance of
cyanosis)
-tetralogy of fallot
-transposition of the great arteries
Tetralogy of fallot
-most common cause of cyanotic
congenital heart disease
-incidence 8-10%
4 defects
1. ventricular septal defect
2. pulmonary aa stenosis
3. L ventricle hypertrophy
4. R aortic valve defect
transposition
-abnormal truncal separation results
in
-aorta
arising from RV
-pulmonary
aa arises from LV
Coarctation of the Aorta
-important obstructive congenital
heart disease
-incidence: 5% of congenial heart disease-isolated
anomaly in about 50% of cases
-preductoal-infantile coarctation-narrowing of aortic isthmus (b/w left subclavian and ductus arteriosus)