Lecture 14 - Cardiovascular disease II Flashcards
what is the definition of congestive heart failure?
CHF is the failure of the heart to pump an adequate amount of blood to supply the metabolic requirements of the organs
*May be due to pathologic conditions inside or outside the heart
what are the 3 compensatory mechanisms the body uses in CHF
- Myocardial hypertrophy
- Ventricular dilation
- Physiologic mechanisms
one of the compensatory mechanisms of CHF is myocardial hypertrophy what are the effects of this?
helps initially, but the larger muscle fibers require more oxygen from the capillaries, which typically is not available
what are the physiologic mechanisms of congestive heart failure?
- increased heart rate
- increased intravascular volume
- re-distribution of blood flow
- increased catecholamines
what is the etiology (the cause, set of causes, or manner of causation of a disease or condition) of congestive heart failure?
- Ischemic heart disease
- Hypertension
- Myocarditis
- Cardiomyopathy
- Valvular disease
what are the 4 manifestations (failures) of CHF?
- Right ventricular failure
- Left ventricular failure
- Left and/or right ventricular failure
- CHF due to left ventricular failure eventually leads to right ventricular failure
what is the cause or manifestation of right ventricular failure?
- congestion of liver (zonal or “nutmeg” pattern) and spleen
- edema or subcutaneous tissue (feet and ankles)
what is the cause/ manifestation of left ventricular failure?
pulmonary edema
what is the cause/ manifestation of left and/or right ventricular failure?
cerebral hypoxia
congenital heart disease may be caused by what two factors?
chromosomal anomalies or environmental factors
*In most cases a specific cause cannot be identified
in the US how many live births have congenital heart disease?
1-8 / 1000
congenital heart disease is divided into what two forms?
cyanotic
noncyanotic
*Congenital heart diseases include shunts (abnormal communications b/w chambers); abnormal connections b/w chambers and blood vessels; and absence of normal connections
Describe the cyanotic form of congenital heart disease
shunting of poorly-oxygenated systemic venous return to systemic arterial circulation, bypassing the lungs
what are 3 examples of noncyanotic congenital heart disease?
atrial septal defect
ventricular septal defect
patent ductus arteriosus
what is happening in an atrial septal defect?
allows shunting of blood between the atria
what is happening in ventricular septal defect?
allows shunting between the ventricles
patent ductus arteriosus should close within a few days after birth and it connects what two structures?
it connects the aorta and pulmonary artery
what are 2 examples of cyanotic congenital heart disease?
tetralogy of fallot
transposition of the great arteries
what are the four anomalies in tetraology of fallot?
- Ventricular septal defect
- Narrowing of right ventricular outflow
- Overriding of the aorta over VSD
- Right ventricular hypertrophy
what is meant by transposition of the great arteries in cyanotic congenital heart disease?
the right ventricle empties into the aorta, the left ventricle empties into the pulmonary artery
what is the pathogenesis of ischemic heart disease (IHD)
- narrowing of coronary arteries (usually at least 75%) by atherosclerosis
- Gradual narrowing may lead to opening of collateral arteries
- coronary artery thrombosis initiated by fissure in the fibrous cap of an atherosclerotic plaque
more than 90% of IHD is due to what?
coronary artery atherosclerosis
what other factrs can lead to ischemic heart disease?
- increase myocaridal oxygen demand (hypertension)
- diminished blood volume (hypotenstion/shock)
- reduced oxygenation (pneumonia, CHF)
- Reduced oxygen carrying capacity (anemia)
what are the different types of IHD (4 of of them - clinical presentation may include one or more)
- Angina pectoris
- Acute myocardial infarction
- Chronic IHD with CHF
- Sudden cardiac death
what is the definition of angina pectoris?
“chest pain” of several minutes duration usually associated with exercise or emotional stress and relieved by rest
- No myocardial necrosis occurs
- In unstable angina, the episodes of chest pain become more frequent and the pain becomes more severe
what is the clinical presentation of acute myocardial infarction?
chest pain shortness of breath nausea/ vomiting diaphoresis low grade fever
what are the 2 diagnostic tests for acute myocardial infarction?
- ECG changes
2. Elevation of serum enzymes (creatine kinase; CK-MB) and troponin derived from necrotic myocytes
what is the pathology (what are the steps of formation) of acute myocardial infarction?
- coagulation necrosis (few hours)
- Neutrophil infiltration (few days)
- granulation tissue (1 week)
- scar formation (weeks - months)
what methods are used to treat acute myocardial infarction?
- Placement of stents to open the coronary arteries clogged by atherosclerotic plaques
- Coronary artery by-pass grafts (CABG)
- “clot-busting” drugs such as tissue plasminogen activator (TPA)
- Reperfusion injury is a risk of these treatments however
what are the 7 complications of myocardial infarction?
- arrhythmia and sudden death
- CHF/ shock
- mural thrombus/ emboli
- myocardial rupture
- mitral valve regurgitation
- ventricular aneurysm
- chronic ischemic heart disease
what is chronic IHD with CHF?
Progressive cardiac decompensation following acute MI or secondary to smaller ischemic events, with eventual mechanical pump
what is sudden cardiac death?
sudden onset of ischemia-induced cardiac arrhythmia with or without myocardial necrosis (infarction)
- This may occur in individuals with or without a previous history of IHD
what is the difference between primary and secondary cardiomyopathy?
- primary - the disease is solely or predominantly confined to the heart muscle
- secondary - the heart is involved as part of a multi-system disorder
what are the 3 morphologic patterns of cardiomyopathy?
dilated
hypertrophic
restrictive
what is dilated cardiomyopathy?
heterogeneous group of cardiac diseases which may be primary or secondary, genetic or acquired
- dilation of all 4 heart chambers
- histology shows variable fibrosis and myocyte hypertrophy
- poor ventricular contractility (systolic dysfunction)
dilated cardiomyopathy has a hereditary basis in what percentage of cases?
20-50%
what is hypertrophic cardiomyopathy?
- A primary, genetic cardiomyopathy
- disorder of sarcomeric proteins (myosin, myosin binding protein C, troponin T)
- inherited as autosomal dominant with variable expression
- inappropriate (spontaneous) myocardial hypertrophy, asymmetric hypertrophy which is greater in the interventricular septum than the left ventricular free wall and often obstructs the left ventricular outflow tract
- characteristic histology is disarray of cardiac myocytes and fibrosis
what is restrictive cardiomyopathy?
- decrease in ventricular compliance (wall is stiffer), resulting in impaired ventricular filling during diastole
- can be idiopathic or associated with other conditions that happen to affect the myocardium, such as radiation fibrosis, amyloidosis, hemochromatosis, and sarcoidosis
what is the definition of myocarditis?
inflammation involving the myocardium
what is the most common cause of myocarditis in the US?
viral infection (coxsackle A and B, other Enteroviruses) *It can also be caused by bacterial, fungal, and parasite organisms
what are some non-infectious causes of myocarditis?
toxins, hypersensitivity reactions and auto-immune disorders
*In some cases the etiology is unknown
in myocarditis, viral infection produces what?
lymphocytic infiltrate with foci of necrosis
in myocarditis, pyogenic bacteria causes what?
abscesses
parasites (such as trypanosomes in Chagas disease - found in south america) infect what?
individual myocytes or are in interstitial areas with surrounding inflammatory cells
in myocarditis the hypersensitivity from the drugs causes what?
perivascular inflammatory infiltrate with many eosinophils
