02 - Heart

Question 1

Congestive Heart Failure (CHF)
Definition
Forward failure
Backward failure

Answer 1

Defined as a clinical syndrome resulting from deficient cardiac stroke volume with inability of the cardiac output to keep pace with the venous return.
Forward failure secondary to (Primary pump failure, problems with contraction of heart, compromises contractility, directly reduces stroke volume)
1) Primary CHF
2) Decreased CO
Backward failure secondary to (failure as response that’s not related to contraction of heart)
1) Increased workload
2) Increased pressure load
3) Increased blood volume

Question 2

Left-sided Heart Failure

Causes

Answer 2

a. Ischemic heart disease (or frank MI) Left side gets hit hard by ischemic heart disease. Forward failure.
b. Hypertension (systemic hypertension) Backwards failure.
c. Valvular disease – aortic stenosis or mitral regurgitation (what does valve regurgitation mean? Blood goes backwards. Possible to have aortic regurgitation, but not as common as mitral regurgitation. Regurgitation is BACKWARD failure because it increases workload on heart)
d. Primary myocardial disease (not common, cardiomyopathy and myocarditis (heart muscle pathology), forward failure)

Question 3

Left-sided Heart Failure

Gross morphological changes

Answer 3

left ventricular hypertrophy and dilation

Question 4

Left-sided Heart Failure

Effects on organs and symptomatology

Answer 4

a. Lungs
1) Chronic passive congestion and pulmonary edema.
2) Lung congestion and effusions predispose to pneumonia.
3) “Heart failure cells” and brown induration of the lung –

4) Clinical manifestations
a) Dyspnea, especially exertional – most common manifestation

b) Orthopnea
c) Paroxysmal nocturnal dyspnea
d) Cough (productive)
e) Cyanosis – in advanced cases
b. Other Organs
1) Brain: Cerebral hypoxia –Irritability, restlessness, stupor +/- coma
2) Kidney: Reduced renal perfusion and prerenal azotemia – Fluid retention may cause peripheral edema (usually R CHF, but can also happen in L CHF)

Question 5

Right-sided Heart Failure

Causes

Answer 5

a. Most often follows left-sided heart failure (Backward)
b. Valvular disease – pulmonic stenosis or tricuspid regurgitation (Backward)
c. Congenital left-to-right shunts (Increases volume in right side) (Backward)
d. Intrinsic lung diseases = cor pulmonale group of ds that are in lung that increases pressure it takes for arterial circulation to go through lungs, causes increased pulmonary resistance, usually chronic (Backward)
e. Cardiomyopathy or myocarditis (Ds that are whole heart at once, both left and right) (Forward)

Question 6

Right-sided Heart Failure

Effects on organs

Answer 6

a. Liver
1) Chronic passive congestion causing nutmeg liver
2) Central hemorrhagic necrosis –
3) Cardiac sclerosis –
b. Spleen – congestive splenomegaly (deep purple)
c. Kidney – congestion and hypoxia lead to marked fluid retention.
d. Brain – congestion and hypoxia (Venous congestion with hypoxia, S/S: same as from L CHF, usually occurs in very severe cases. Brain findings are not common for both sides!)
e. Subcutaneous tissues – peripheral edema and possible anasarca
f. Portal system – portal hypertension; may lead to ascites. (ascites usually a late finding!)

Question 7

Ischemic heart disease = ?
Definition
Patterns

Answer 7

Ischemic Heart disease = Coronary heart disease
Defined as heart ds due to an imbalance between supply and demand for oxygen to the myocardium
1. Angina Pectoris (AP)
2. Myocardial Infarction (MI)
3. Sudden Cardiac Death (SCD)
4. Chronic Ischemic Heart Disease (CIHD) (Most common!)

Question 8

Ischemic Heart Disease

Pathogenesis

Answer 8

1. Oxygen deficiency is primarily due to severe coronary atherosclerosis with stenosing plaques.

a. Critical stenosis will obstruct 70% to 75% of coronary artery lumen, but usually asymptomatic unless there is increased demand or other complicating factor.
b. Fixed stenosis of 90% can cause symptoms at rest.
c. Pattern of IHD depends on severity and persistence of hypoxia

2. Other Influencing Factors
   a. Intraluminal thrombosis overlying a ruptured or fissured plaque (over C[oronary]-ATH) –

b. Platelet aggregation – platelets adhering to wall but without activation of coagulation system! Plavix and aspirin(Cox-1) can prevent platelet aggregation!
c. Vasospasm –
d. Increased myocardial demand –
e. Reduced oxygen-carrying capacity of the blood – Anemia
f. Sudden drop in blood pressure (shock) –
g. Coronary emboli – rare
h. Coronary arteritis – Kawasaki dz (vasculitis ds can cause ischemic heart disease in absence of coronary atherosclerosis! The rest can cause IHD in presence of atherosclerosis)

Question 9

Ischemic Heart Disease

Mechanism

Answer 9

Myocardial hypoxia

Due to ischemia

Question 10

Angina Pectoris

Definition

Answer 10

1. Defined as paroxysmal attacks of substernal or precordial chest pain or discomfort caused by myocardial ischemia that falls precariously short of inducing infarction.
   a. Hypoxic injury is moderate to severe
   b. Hypoxic injury is reversible!

Question 11

Angina Pectoris

S/S

Answer 11

1. Attacks are sudden, episodic, may be unpredictable
2. Pain may radiate to the left shoulder or arm, even to the jaws.
3. Pain is due to a transient reversible myocardial hypoxia which may be due to combinations of fixed stenosing lesions, vasospasm, platelet aggregation and increased myocardial demand. Because hypoxic injury is reversible, pain is transient

Question 12

Angina Pectoris

Pathogenesis

Answer 12

1) Always have fixed coronary stenosis due to atherosclerosis
2) Which…

Question 13

Angina Pectoris

Patterns

Answer 13

Typical Angina Pectoris
Prinzmetal Angina Pectoris
Unstable Angina Pectoris

Question 14

Typical Angina Pectoris

Answer 14

(Stable Angina Pectoris) most common

1) Ischemia due to stenosing atherosclerosis compounded with increased myocardial demand.
2) Attacks are often precipitated by exertion or emotional stress and are relieved by rest.
3) Pain because of baseline atherosclerosis.
4) Baseline = ok, but if you need more, you can’t get more. Chest pain when they mow lawn, take stairs, etc.
5) Usually do not require medication, or for emergencies
6) Most important thing to do when S/S appear is to rest
7) Episodes are very short

Question 15

Prinzmetal Angina Pectoris

Answer 15

1) Attacks are attributed to vasospasm, (can be very unpredictable) which may be superimposed on fixed stenosis.
2) Attacks may appear even at rest and are relieved by vasodilators such as nitroglycerin.
3) Attacks triggered by vasospasm
a) Can have attacks even when C-ATH is not as severe as in other patterns of IHD
4) Underlying atherosclerosis, sometimes it hasn’t reached critical stenosis
5) Attacks can occur at rest
6) Tx with vasodilators
a) Nitroglycerin
b) Amyl nitrate
c) Some patients may take ongoing medication, others take medication just to treat episodes

Question 16

Unstable Angina Pectoris

Answer 16

1) Multiple mechanisms may be involved in development of attacks.
2) Attacks forewarn of imminent danger of a subsequent acute MI.
3) Pathogenesis usually involved occluded “twig” rather than main coronary artery
a) Occluded twig: smaller branching arteries that has been blocked, usually by a thrombus
4) Defined by change in usual patterns of attacks
a) Increased frequency
b) Increased duration
c) Change in triggering events
5) Clinical significance
a) May be forewarning of acute MI

Question 17

Myocardial infarction

Definition

Answer 17

Defined as ischemic (hypoxic) necrosis of the myocardium. Irreversible hypoxic injury of myocardium due to vascular insufficiency

Question 18

Myocardial infarction

Risk Factors

Answer 18

c. Factors that Increase Risk
1) Age – may be seen from youth to old age; risk increases with age.
2) Sex
a) At 45-54 years old men have 4-5 X risk compared to women.
b) By age 70 years men are affected 2 X as commonly as women.
c) At age 80 years men and women are equally affected.
3) Type A personality –
4) Previous MI

d. Factors that Decrease Risk
1) Regular exercise –

2) Moderate alcohol consumption (red wine) –

Question 19

Myocardial Infarction

Pathogenesis

Answer 19

a. Severe coronary narrowing underlies pathogenesis for myocardial infarcts but does not act alone. Severity of involvement usually occurs as follows:
1) Left anterior descending coronary artery
2) Left circumflex coronary artery
3) Right coronary artery
4) First-order branch of one of the above
5) Left far more often than right

Question 20

Myocardial Infarction

Pathogenesis (PRECIPITATING FACTORS)

Answer 20

(superimposed on coronary atherosclerosis)

1) Thrombosis #1 reason
a) Initiated by plaque fissure, rupture, or intraplaque hemorrhage.
b) For transmural infarcts, 90-95% cases have superimposed thrombosis. Occlusive thrombus usually found in:
• Left anterior descending coronary artery – 40-50%
• Right coronary artery – 30-40%
• Left circumflex coronary artery – 15-20%
c) For subendothelial infarcts, thrombosis is involved in only 20% cases
d) Usually occlusive, causes sudden onset of symptoms

2) Platelet activation –
3) Vasospasm – not very common, vasospasms may not last long enough
4) Hypotensive episode – much less frequent
5) Increased myocardial demand with tachycardia – much less frequent
6) Usually sudden blockages!

Question 21

Myocardial Infarction
Types
Sequence of biochemical and morphological changes

Answer 21

a. Transmural – ischemic necrosis involves the full thickness (or nearly so) of the ventricular wall.
1) Most common and most serious type
2) Ischemic necrosis involves full thickness of myocardial walla
3) Most common in left ventricle
a) Left develops more severe atherosclerosis
b) Thrombus develops more commonly in left than right

b. Subendothelial – necrosis involves not more than the inner one third to half the thickness of the wall.

Sequence of Biochemical and Morphologic Changes in Myocardial Infarction
1-2 minutes Loss of contractility
10 minutes 50% depletion of ATP
20-40 minutes Irreversible cell injury
8-12 hours Gross pallor
First week Pale lesion, red rim
End of first week Sharply-defined soft yellow lesion has red rim
7-10 days Lesion maximally soft and weak
7th week Lesion completely healed by scarring (depends on size of infarct)

Question 22

Myocardial Infarction

Morphological complications of TRANSMURAL Myocardial Infarction

Answer 22

a. Infarction of papillary muscle – can end up with valvular dysfunction, papillary muscle can rupture as well
b. Rupture of infarcted papillary muscle – can result in regurgitation, reduces CO dramatically
c. Fibrinous pericarditis – over area of infarct, over area of pericardium. As it heals, it scars and there can be adhesion of the pericardium with the pericardial sac, can limit its movement
d. Mural thrombosis with risk of embolization – thrombus is crumbly, beating/movement of heart can cause it to break apart and dislodge
e. Rupture of the infarct, may cause cardiac tamponade – cardiac tamponade from day 7-10,
f. Ventricular aneurysm –
g. Scar from old healed myocardial infarction in interventricular septum. Perkinje fibers are in wall, can be disrupted by MI and can result in arrythmia after MI
h. Healed scar may balloon out producing an aneurysm. Predisposed for mural thrombus formation

Question 23

Myocardial Infarction

Symptoms

Answer 23

1) Prodromal symptoms (occur ahead of the attack by days or weeks) may include fatigue, dyspnea, or a change in pattern of angina.
2) Onset presents suddenly with severe precordial pain that may radiate to left shoulder, arm or jaw. Symptoms last 20 minutes to several hours.

3) Pain is often accompanied by
a) Diaphoresis (profuse sweating)
b) Nausea and vomiting
c) Breathlessness (due to hypoxia, pain and anxiety)

4) About 10% to 15% of MIs are asymptomatic (silent) and are diagnoses by ECG changes and serum enzyme studies.
5) Severe precordial pain, may radiate to left shoulder or jaw

Question 24

Myocardial Infarction

Clinical outcomes/sequellae

Answer 24

1) 10-20% are uncomplicated cases. Symptoms decline leading to healing and recovery.

2) 80-90% patient develop complications.
a) 75-95% develop arrhythmias. (75%)
b) 10-15% go into cardiogenic shock.
c) 1-5% develop rupture of free wall, septum, or papillary muscle. May lead to cardiogenic shock, cardiac tamponade or ultimate CHF. (60%)
d) 15-49% develop embolism of a mural thrombus. May lead to stroke, gangrene or internal organ infarctions.
e) 60% develop left ventricular congestive heart failure with mild to severe pulmonary edema.
f) Arrhythmias – 75% (sometimes can be controlled by meds if severe enough or a pacemaker, this complication is early and won’t disappear)
g) CHF – 60% (late complication, weeks, months even decades)
h) Embolism of mural thrombus – 15-49% (Early complication, wide range due to actually finding it)
i) Cardiogenic shock – 10-15% (Early complication, usually right after infarct occurs, within 24 hrs)
j) Rupture of myocardium – 1-5% (Early complication)(7-10 days is still “early”)
DEATH USUALLY DUE TO CHF

Question 25

Myocardial Infarction

Prevention/Tx

Answer 25

a. Coronary bypass surgery Not as common today
b. Angioplasty Doesn’t work too well today
c. Cardiac stents Better success than angioplasty
d. Aspirin, Coumadin, Plavix Usually prescribed after surgery. Small arteries more likely to be affected by platelet aggregation. Coumadin interferes with cascade, not aggregation
e. Lifestyle changes – Usually most difficult to do, “hardest pill to take”

Question 26

Sudden Cardiac Death

Definition

Answer 26

1. Defined as unexpected death from cardiac causes within 1 hour of the onset of acute symptoms. (Some definitions extend time frame to 24 hours.)

Question 27

Sudden Cardiac Death
Epidemiology
Etiology

Answer 27

2. Epidemiology

a. Causes 300,000-400,000 deaths annually in the US.
b. Is responsible for more than half of all deaths from IHD.

3. Etiology

a. 75-90% cases are attributable to IHD. (IHD – CHD)
b. Other causes of sudden cardiac death include cardiomyopathy, mitral valve prolapse, aortic valve stenosis, and anomalies of the cardiac conduction systems.

Question 28

Sudden Cardiac Death

Pathogenesis

Answer 28

a. Marked stenosing atherosclerosis of at least one coronary artery.
b. The ultimate mechanism of death is almost always a lethal arrhythmia (asystole, ventricular fibrillation, etc.).
c. Recent thrombosis found in only 10-35% cases.
d. Usually a severe arrhythmia is the cause of SCD
e. Defibrillation is the standard of care now

Question 29

Sudden Cardiac Death

Treatment

Answer 29

5. Treatment – Prompt electrocardioversion may revive patient and prevent death
   a. Ventricular fibrillation is most common arrhythmia
   b. Asystoly – no beat, flatline, not arrhythmia
   c. If they survive, may need permanent pacemaker

Question 30

Chronic Ischemic Heart Disease

Definition

Answer 30

1. This is actually the most common form of ischemic heart disease!
2. This diagnosis is applied to the form of heart disease that appears insidiously in older people who develop ECG changes and congestive heart failure as a consequence of long-term, progressive ischemic myocardial damage.
   a. Usually has severe stenosis that develops over time and chronic ischemic heart disease. Some patients develop CHF before they know they have IHD.

Question 31

Chronic Ischemic Heart Disease

Morphological changes

Answer 31

a. Gross – heart may be normal weight, or smaller and dark brown. Left ventricular dilation is mild. Atherosclerosis is often severe enough to cause occlusions.
1) C-ATH, often with occlusions
2) Heart of normal weight or smaller
3) Dark brown color (due to lipofuscin)
4) Mild left ventricular dilation
b. Microscopic – diffuse myocardial atrophy, lipofuscin deposits within myocytes, diffuse fibrosis (myocardial fibrosis) mostly around vessels.

Question 32

Chronic Ischemic Heart Disease

Clinical course

Answer 32

a. Due to insidious nature, may be asymptomatic until CHF develops.
b. May have history of angina, or previous episode of myocardial infarction, years prior to onset of congestive heart failure.
c. Scarring of conduction system may cause arrhythmias.
d. Most patients die of unrelated causes.

Question 33

Hypertensive Heart Disease

Criteria for diagnosis

Answer 33

A. Minimal anatomic criteria necessary for diagnosis of hypertensive heart disease are:
1. Left ventricular hypertrophy
2. Absence of other cardiac changes
3. May ultimately progress to CHF
4. (different from hypertension, it is the result of what happens to left side of heart with long standing hypertension that has not been adequately controlled)
5. Dilation w/o hypertrophy = CHF??? (What if you just have only dilation?)
B. A clinical history of HTN is helpful, but not necessary. It is also helpful if clinical history shows no evidence of conditions that might cause left ventricular hypertrophy.

Question 34

Hypertensive Heart Disease
Complications/sequellae
S/S

Answer 34

Hypertension predisposes to atherosclerosis. Although adequate cardiac output is maintained for years, the hypertrophied heart eventually fails.
Clinical signs – none. Symptoms to patient are usually not detected until it progresses to CHF

Question 35

Cor Pulmonale

Definition

Answer 35

A. Cor pulmonale constitutes right ventricular enlargement secondary to pulmonary hypertension. Pulmonary hypertension is in turn caused by disorders that affect either the structure or function of the lungs such that there is increased resistance to blood flow through the lungs.
1. Problem is due to increased resistance in the lung.

Question 36

Cor Pulmonale
Acute/Chronic
Pathogenesis

Answer 36

B. Acute cor pulmonale causes right ventricular dilation. But dilation is transient and will disappear if the underlying pulmonary condition is corrected. Acute cor pulmonale can progress to chronic cor pulmonale.

C. Chronic cor pulmonale is characterized anatomically by right ventricular hypertrophy in the absence of ventricular dilation. This is the form that may be seen at autopsy examination.

D. Pathogenesis

1. Primary lung ds cause increased resistance to blood flow through lungs
2. Pulmonary HTN develops
3. …

Question 37

Congenital Heart Diseases
Common S/S
List of diseases

Answer 37

The most common clinical sign of a congenital heart defect is a heart murmur.
Left to Right shunts (LATE cyanosis)
1. Ventricular Septal Defect (VSD) = 31%
2. Atrial Septal Defect (ASD) = 10%
3. Patent Ductus Arteriosus = 10%
Right to Left shunts
1. Tetralogy of Fallot = 6%
2. Transposition of the Great Vessels = 4%
Obstructive Noncyanotic Congenital Anomalies
1. Coarctation of the Aorta = 7%
2. Valvular Anomalies

a. Stenosis (6%) – narrowing or partial obstruction of valve opening
b. Atresia – complete obstruction of valve lumen
c. Valve anomalies – bicuspid aortic valve, etc.

3. Miscellaneous
   a. Valvular stenosis
   1) Narrowing or partial obstruction of valve opening
   b. Valvular atresia
   1) Complete obstruction of valve lumen, does not even form
   c. Other
   1) Bicuspid aortic valve – 2 leaflets instead of 3, can have regurgitation
   d. Hyperplastic left heart syndrome – indication for infant heart transplant

Question 38

Ventricular Septal Defect
Definition
Occurrence

Answer 38

Defined by the presence of a hole in the ventricular septum. (L2R shunt!)

1) 90% commonly are located in the thin, membranous portion of the ventricular septum just below the aortic valve.
2) Remainder are located below the pulmonic valve or within the muscular septum.
3) Won’t get cyanosis unless right side undergoes hypertrophy
4) Definitely at risk for endocarditis
5) Usually located high in the intramembraneous portion of the septum
a) Usually the most significant, can be very large

This is the most common congenital heart defect. There has been a significant increase of VSD in the US.

Question 39

Ventricular Septal Defect

Clinical significance

Answer 39

Clinical significance depends on size of defect.

1) Defects < 0.5 cm may close spontaneously, cause loud systolic murmur and possible systolic thrill.
2) Small to moderate-sized defects may produce jet lesions that predispose to infective endocarditis.
3) Large defects produce severe shunting with consequent cyanosis and pulmonary complications.

Question 40

Atrial Septal Defect
Definition
Clinical findings

Answer 40

a. Defined by the presence of a hole in the atrial septum above the level of the valves. (L2R shunt!)
b. Clinical Findings
1) Due to lower pressures, symptoms may not develop for years.
2) Defects < 1 cm are well tolerated.
3) Larger lesions can cause heart failure from severe pulmonary HTN.
4) Infective endocarditis is rare.
5) Heart murmur – may be minimal
6) Flow reversal – uncommon
a) Cyanosis
b) Possible CHF
c. Under reported because foramen ovale is already there during development and is supposed to close after birth. May not be detected until later in life.
d. May not be significant unless there is a large hole

Question 41

Patent Ductus Arteriosus
Definition
Clinical findings

Answer 41

a. Defect occurs when the ductus joining the pulmonary artery to the aorta fails to close at birth. Most occur as an isolated defect. (L2R shunt!)
b. Clinical Findings
1) Produces a hard continuous machine-like murmur and often a systolic thrill.
2) Initial shunting is left-to-right so there is no cyanosis.
3) Later flow reverses causing cyanosis. Late cyanosis
4) Increases risk for infective endocarditis.
5) Can cause CHF
6) Shunting causes left sided blood to go to lungs. This is a problem because it causes a volume overload, which can cause pulmonary hypertension, R CHF, cor pulmonale.

Question 42

Tetralogy of Fallot

Components

Answer 42

R2L Shunt!

1) Ventricular septal defect
2) Dextraposed aorta that overrides the ventricular septal defect (straddles septal defect, sometimes called overriding aorta)
3) Obstruction of right ventricular outflow (pulmonic stenosis – pulmonica valve opening is reduced, can be very severe or pin sized, only way out is through stenosis)
4) Right ventricular hypertrophy (occurs during fetal life, right chamber blood hypertrophies to compete with left side to compensate for obstruction of blood flow)
5) Defect is high, sometimes above aortic leaflets!
6) Babies will be blue, but can vary depending on severity which depends on how closed the pulmonic valve is.
7) Patent ductus arteriosus can be beneficial and meds may be given to keep it open, but this is NOT a defining characteristic of tetralogy of fallot.

Question 43

Tetralogy of Fallot

Clinical manifestations

Answer 43

Severity of clinical manifestations is directly related to the degree of obstruction of right ventricular outflow.
1) Mild pulmonic stenosis with a large septal defect produces left- to-right shunting with no cyanosis.
2) With more obstruction, shunting is right-to-left and produces cyanosis, pulmonary HTN and its consequences.
3) Infective endocarditis is a risk.
4) S/S
a) Depends on severity of pulmonic stenosis
• Larger the defect, less shunting
• More obstruction of right ventricular outflow goes with more cyanosis
b) Cyanosis
c) Dyspnea
d) Hypoxemia
e) Increased risk of infective endocarditis

Question 44

Transposition of the Great Vessels
Definition
Prognosis

Answer 44

R2L Shunt!

a. Features reversed position of the pulmonary artery and aorta.
b. In corrected transposition, the venous input is also transposed.
c. Prognosis – Fatal if not corrected.
d. Def – reversal of positioning of the aorta and pulmonary artery. Right ventricle receives venous blood, leaves through aorta. Aorta arises from r vent, l vent receives blood and goes to pulmonary artery and back to lungs. You get 2 closed systems! Ductus arteriosus needs to be kept open until surgery can be done! VERY SERIOUS DEFECT!
e. More common in baby boys
f. “Corrected” transposition of great vessels
1) Arterial output AND venous intake are both transposed
a) R heart receives blood from lungs, pumps to body
b) L heart receives blood from body, pumps to lungs
c) Anatomically weaker side bears the workload
2) Prognosis
a) Compatible with long life, with healthy lifestyle
b) Risk of CHF from long term workload of the anatomically weaker right heart

Question 45

Coarctation of the Aorta
Definition
Forms

Answer 45

a. Defined as constriction or narrowing of the aorta.
b. Half of cases are associated with other anomalies.

c. Preductal Form
1) Severe narrowing occurs proximal to the ductus arteriosus (usually have PDA).
2) Blood shunts from the pulmonary artery to the systemic vasculature.
3) Infants often also have hypoplastic left heart.
4) Most do not survive past infancy.
5) Most often found in infancy
6) Poor prognosis, usually requires heart transplant if constriction is severe

d. Postductal Form
1) Narrowing occurs distal to the ductus arteriosus (which closes).
2) Only a short segment is narrowed and lesion may appear as a ring.
3) Degree of stenosis varies greatly.
4) Most children are asymptomatic and not diagnosed until adulthood.
5) Clinical Manifestations –
6) Can be surgically corrected
7) Easily fixed

Question 46

Valvular anomalies

Answer 46

a. Stenosis (6%) – narrowing or partial obstruction of valve opening
b. Atresia – complete obstruction of valve lumen
c. Valve anomalies – bicuspid aortic valve, etc.

Question 47

Endocardial and Valvular Disease

Answer 47

A. Mitral Valve Prolapse
B. Rheumatic Fever and Rheumatic Heart Disease
C. Infective Endocarditis
D. Complications of Artificial Valves
1. Paravalvular leaks – Same issues as regurgitation for natural valves
2. Thromboembolic complications – May embolize
3. Risk for infective endocarditis – Increased risk
4. Deterioration – May need replacement

Question 48

Mitral Valve Prolapse
Definition
Mechanism

Answer 48

1. The valve leaflets prolapse, ballooning backward toward the left atrium during systole. Prolapse is usually not a big problem but can cause closure. Wide range of complications
   a. Valve leaflets open up like parachute
   b. May or may not have regurgitation
2. Mitral valve prolapse is the most common cardiac valve disease in the US.
3. Disease Mechanism
   a. Most are isolated defect
   b. Some are due to Marfan syndrome
   c. Few are other Mendelian defects – X-linked recessive or autosomal dominant

Question 49

Mitral Valve Prolapse
Clinical features
Clinical consequences

Answer 49

4. Clinical Features
   a. Age and gender predilection – 20-40 year old females (distinctly more common in women)
   b. 3-5% of general adult pop
   c. S/S
   1) Often asymptomatic murmur
   2) Chest pain, palpitations, arrhythmia
5. Clinical Consequences
   a. Mild cases may have no untoward consequences.
   b. Mitral valve regurgitation
   c. Chest pain
   d. Arrhythmia
   e. Eventual CHF
   f. Sudden death
   g. Predisposes to infective endocarditis only if there is regurgitation with the prolapse

Question 50

Rheumatic fever and Rheumatic heart disease
Definition
Epidemiology

Answer 50

1. Rheumatic fever (RF) is an acute febrile, immune-mediated inflammatory disease, principally of children, that follows shortly after an infection with group A β-hemolytic streptococci. NOT an active infection, it is a response to an infection! GAS – very antigenic, m protein makes it very antigenic. Stimulates potent host response.
2. Epidemiology
   a. Historically, only 3% of persons who got strep throat got RF. Suggests genetic predisposition
   b. Incidence and mortality from RF and RHD have declined in the U.S.
   1) Antibiotics, better socioeconomic conditions in general, reduction of virulence of organism
   c. Decline is attributed to better control of streptococcal pharyngitis, and some reduction in virulence of the organism.

Question 51

Rheumatic fever and Rheumatic heart disease

Pathogenesis

Answer 51

Pathogenesis

a. An M protein present on the surface of specific stains of streptococcal organisms evokes antibodies that are cross-reactive with human epitopes.
b. Although these antibodies may not be directly responsible for tissue lesions, they work in concert with other immune mechanisms to produce acute systemic disease.
c. After acute manifestations subside, there may be permanent damage to tissues, particularly to the heart valves.
d. Attacks various tissues
1) Heart: endo, myo and epicardium. Frequent site of attack, not universal.
2) Joints and skin

Question 52

Rheumatic fever and Rheumatic heart disease

Morphological manifestations

Answer 52

Morphologic Manifestations of Rheumatic Heart Disease

a. The pathognomonic lesion of RF is the Aschoff body. In acute RHD, Aschoff bodies may be found in all three heart layers.
b. Fibrinous (“bread-and-butter”) pericarditis is common.
c. Valves (mitral most often) develop vegetations along leaflet edges. Vegetations become fibrotic, and then calcified with time.
1) Red swollen masses of fibrin and inflammatory cells
2) Mitral valve most commonly affected (almost always!)
d. Affected valves may become stenotic and/or regurgitate.
e. Late valve changes
1) Stenosis and/or regurgitation

Question 53

Rheumatic fever and Rheumatic heart disease

Clinical manifestations

Answer 53

5. Clinical Manifestations of Rheumatic Fever
   a. RF most often occurs between the ages of 5 and 15 years.

b. Clinical Course
1) Onset is typically 2-3 weeks following streptococcal tonsillitis or pharyngitis. Range of onset can be 10 days to six weeks!
2) Signs and symptoms
a) Joint pain and swelling (polyarthritis)
b) Skin rash
c) Heart murmur – only if heart is involved!
3) Rheumatic heart disease
a) Risk of heart involvement is 66% for first episode of RF.
b) Risk increases to 100% at second episode of RF.
c) Although acute stage is rarely fatal, most serious of acute manifestations are heart-related.
4) Laboratory findings
a) By time RF develops, can no longer culture strep organism.
b) Antibodies are detectable in the serum. Characteristic antibodies are antistreptolysin O (ASO) and antistreptokinase (ASK).

Question 54

Rheumatic fever and Rheumatic heart disease

Clinical consequences/sequelae

Answer 54

6. Clinical Consequences and Sequelae
   a. 50% risk of recurrence – there is increased vulnerability to reactivation of the disease with subsequent streptococcal infections.
   b. Mitral valve stenosis – valve replacement may become necessary.
   c. Mitral valve regurgitation – biggest problem that happens as a result of this is CHF. This is how most die
   d. CHF may eventually develop due to mitral valve stenosis and regurgitation. CHF – late finding
   e. Increased risk of infective endocarditis – only if RHD was present (look for murmur!)
   1) If there is a murmur, there is heart involvement! There was valve damage!
   f. Rheumatic fever is the #1 reason why people have valve replacements

Question 55

Infective endocarditis
Definition
Morphological manifestations

Answer 55

1. Infective endocarditis is characterized by colonization or invasion of the heart valves by microbiologic agents, leading to the local formation of thrombotic masses laden with organisms — so-called infective vegetations. Active infection!
2. Morphologic Manifestations – valvular vegetations!

Question 56

Infective endocarditis

Etiology

Answer 56

3. Etiology – requires interaction of three factors:
   Presence of  microorganisms  in the circulating blood in a  susceptible host
   a. Infecting Organisms

1) 50-60% of total cases are caused by strains of α streptococci, including strep viridans (produces dextrans, allows adhesion to heart surfaces, sticky!). Disease is usually subacute (organism is not as virulent) and is often called subacute bacterial endocarditis (SBE).
2) 10-20% of total cases are caused by Staph aureus. However, S. aureus is the most common cause of acute infective endocarditis.
3) Other microorganisms – can be viral, fungal, ricketssiae.

Question 57

Infective endocarditis

Complications of artificial valves

Answer 57

1. Paravalvular leaks – Same issues as regurgitation for natural valves
2. Thromboembolic complications – May embolize
3. Risk for infective endocarditis – Increased risk
4. Deterioration – May need replacement

Question 58

Myocardial diseases

List

Answer 58

Myocarditis

Cardiomyopathy

Question 59

Myocarditis
Definition
Etiology

Answer 59

INFLAMMATORY!
1. Defined as myocardial inflammation sufficient to cause clinical manifestations. Reserved for isolated cases!

2. Etiology
   a. Inflammation is the primary mechanism of injury to the myocardium.
   b. Causes of inflammation include
   1) Infections – viruses, Chlamydia, rickettsia, bacteria, fungi, etc.
   2) Immune-mediated reactions – Post-viral, post-streptococcal (RHD), SLE, hypersensitivity rxn
   3) Other – sarcoidosis, giant cell myocarditis

Question 60

Myocarditis
S/S
Complications and sequellae

Answer 60

3. Clinical Signs and Symptoms
   a. May have only subtle ECG changes.
   b. May cause arrhythmias.
   c. Usually develop acute heart failure
   d. Can be short term, but it can take a while for heart to heal
4. Complications and Sequellae
   a. May cause acute CHF.
   b. Rare severe attacks can be lethal.

Question 61

Cardiomyopathy

Definition

Answer 61

NON-INFLAMMATORY!

1. Non-inflammatory myocardial disease that is not attributable to pressure or volume overload.
2. Term is broadly applied to:
   a. Any heart disease due to primary myocardial abnormalities.
   b. Any disease resulting primarily or predominantly from myocardial dysfunction.

Question 62

Pericardial disease

List

Answer 62

Accumulations of fluid in pericardial sac

Pericarditis

Question 63

Pericarditis
Definition
Etiology

Answer 63

1. Defined as inflammation involving the pericardial surface of the heart.
2. Etiology
   a. Primary – almost always viral, but may be bacterial
   b. Secondary – myocardial infarction, uremia, cardiac surgery, SLE, RF, rheumatoid disease, microbial seeding, cancer, radiation, immune-mediated ds

Question 64

Pericarditis
Types
Complications

Answer 64

3. Types
   a. Fibrinous – most common type AKA “bread and butter” pericarditis
   b. Suppurative
4. Complications
   a. With treatment of underlying disorder, most resolve without sequellae.
   b. If chronic, may result in fibrous encasement of heart (restrictive). and adhesions.