Cardiovascular

Question 1

Temporal (Giant Cell) Arteritis

Answer 1

Granulomatous vasculitis that classically involves branches of the carotid artery

Most common form of vasculitis in older adults (> 50 years); usually affects females
Presents as headache (temporal artery involvement), visual disturbances (ophthalmic artery involvement), and jaw claudication. Flu-like symptoms with joint and muscle pain (polymyalgia rheumatica) are often present. ESR is elevated.

Biopsy reveals inflamed vessel wall with giant cells and intima! fibrosis (Fig. 7.2). i. Lesions are segmental; diagnosis requires biopsy of a long segment of vessel, and a negative biopsy does not exclude disease.

Treatment is corticosteroids; **high risk of blindness without treatment **

Question 2

Takayasu Arteritis

Answer 2

Granulomatous vasculitis that classically involves the aortic arch at branch points

Presents in adults < 50 years old (classically, young Asian females) as visual and neurologic symptoms with a weak or absent pulse in the upper extremity (‘pulseless disease’).

ESR is elevated.

Treatment is corticosteroids.

Question 3

Polyarteritis Nodosa

Answer 3

Necrotizing vasculitis involving multiple organs; lungs are spared.
Classically presents in young adults as hypertension (renal artery involvement), abdominal pain with melena (mesenteric artery involvement), neurologic disturbances, and skin lesions. Associated with serum HBsAg

Lesions of varying stages are present. Early lesion consists of transmural inflammation with fibrinoid necrosis; eventually heals with fibrosis, producing a ‘string-of-pearls’ appearance on imaging
Treatment is corticosteroids and cyclophosphamide; fatal if not treated

Question 4

Kawasaki Disease

Answer 4

Classically affects **Asian children < 4 years old **

Presents with nonspecific signs including fever, conjunctivitis, erythematous rash of palms and soles, and enlarged cervical lymph nodes

Coronary artery involvement is common and leads to risk for (1) thrombosis with myocardial infarction and (2) aneurysm with rupture.

Treatment is aspirin and IVIG; disease is self-limited.

Question 5

Buerger Disease

Answer 5

1. Necrotizing vasculitis involving digits
2. Presents with ulceration, gangrene, and autoamputation of fingers and toes;

Raynaud phenomenon is often present,
3. Highly associated with heavy smoking; treatment is smoking cessation.

Question 6

Wegener Granulomatosis

Answer 6

Necrotizing granulomatous vasculitis involving nasopharynx, lungs, and kidneys

Classic presentation is a middle-aged male with sinusitis or nasopharyngeal ulceration, hemoptysis with bilateral nodular lung infiltrates, and hematuria due to rapidly progressive glomerulonephritis.

Serum c-ANCA levels correlate with disease activity,

Biopsy reveals large necrotizing granulomas with adjacent necrotizing vasculitis

Treatment is cyclophosphamide and steroids; relapses are common

Question 7

Microscopic Polyangiitis

Answer 7

Necrotizing vasculitis involving multiple organs, especially lung and **kidney, **and skin with pauchi-immune glomerulonephritis and palpable purpura.

Presentation is similar to Wegener granulomatosis, but nasopharyngeal involvement and granulomas are absent.

Serum p-ANCA (MPO- ANCA) levels correlate with disease activity.

Treatment is corticosteroids and cyclophosphamide; relapses are common.

Question 8

Churg-Strauss Syndrome

Answer 8

1. Necrotizing granulomatous inflammation with eosinophils involving multiple organs, especially lungs and heart
2. Asthma and peripheral eosinophilia are often present.
3. Serum p-ANCA (MPO ANCA) levels correlate with disease activity.

Question 9

Henoch-Schön lein Purpura

Answer 9

Vasculitis due to IgA immune complex deposition; most common vasculitis in children

Presents with palpable purpura on buttocks and legs, CI pain and bleeding, and

hematuria (IgA nephropathy); usually occurs following an upper respiratory tract infection

Disease is self-limited, but may recur; treated with steroids, if severe

Question 10

Atherosclerosis

Answer 10

Intimal plaque that obstructs blood flow

Consists of a necrotic lipid core (mostly cholesterol) with a fibromuscular cap (Fig. 7,5); often undergoes dystrophic calcification

Involves large- and medium-sized arteries; abdominal aorta, coronary artery, popliteal artery, and internal carotid artery are commonly affected.

Pathogenesis
1. Damage to endothelium allows lipids to leak into the intima.

2. Lipids are oxidized and then consumed by macrophages via scavenger receptors, resulting in foam cells.

Inflammation and healing leads to deposition of’extracellular matrix and proliferation of smooth muscle.

Histology

1. Begins as fatty streaks (flat yellow lesions of the intima consisting of lipid-laden macrophages); arise early in life (present in most teenagers)
2. Progresses to atherosclerotic plaque

Question 11

Arteriolosclerosis

Answer 11

Narrowing of small arterioles; divided into hyaline and hyperplastic types:

Hyaline arteriolosclerosis is caused by proteins leaking into the vessel wall, producing vascular thickening; proteins are seen as pink hyaline on microscopy (Fig. 7.7).

1. Consequence of long-standing benign hypertension or diabetes
   2, Results in reduced vessel caliber with end-organ ischemia; classically produces glomerular scarring that slowly progresses to chronic renal failure

Hyperplastic arteriolosclerosis involves thickening of vessel wall by hyperplasia of smooth muscle (‘onion-skin appearance)

1. Consequence of malignant hypertension. Results in reduced vessel caliber with end-organ ischemia

May lead to fibrinoid necrosis of the vessel wall with hemorrhage; classically causes acute renal failure with a characteristic ‘flea-bitten’ appearance

Question 12

Monkeberg Medial Calcific Sclerosis

Answer 12

Calcification of the media of muscular (medium-sized) arteries (radial or ulnar); nonobstructive

Not clinically significant; seen as an incidental finding on x-ray or mammography

X-ray: “Pipesteam” arteries

Question 13

Hypertension

Answer 13

Systolic BP >140 mmHg or diastolic BP > 90 mmHg

Risks: age, obesity, diabetse, smoking, genetics, Black > white > Asian

Essential HTN: increased CO or TPR

secondary HTN: renal disease

Hypertensive Emergency: Severe hypertension >180/120 with evidence of acute, ongoing target organ damange (papilledema, mental status change)

Question 14

Malignant vs. Benign HTN

Answer 14

Benign HTN is a mild or moderate elevation in blood pressure;

• most cases of HTN are benign.
• Clinically silent; vessels and organs are damaged slowly over time.

Malignant HTN is severe elevation in blood pressure (> 200/120 mm Hg}; comprises < 5% of cases

• May arise from preexisting benign HTN or de novo
• Presents with acute end-organ damage (e.g., acute renal failure, headache, and papilledema) and is a medical emergency

Question 15

Aortic Dissection

Answer 15

Intimal tear with dissection of blood through media of the aortic wall

• Occurs in the proximal 10 cm of the aorta (high stress region) with preexisting weakness of the media
• Most common cause is hypertension (older adults); also associated with inherited defects of connective tissue (younger individuals)
  1. Hypertension results in hyaline arteriosclerosis of the vasa vasorum; decreased flow causes atrophy of the media.
  2, Marfan syndrome and Ehlers-Danlos syndrome classically lead to weakness of the connective tissue in the media (cystic medial necrosis).

Presents as sharp, tearing chest pain that radiates to the back

**- ** Complications include pericardial tamponade (most common cause of death), rupture with fatal hemorrhage, and obstruction of branching arteries (e.g., coronary or renal) with resultant end-organ ischemia.

Question 16

Thoracic Aneurysm

Answer 16

Balloon-like dilation of the thoracic aorta

Due to weakness in the aortic wall. Classically seen in tertiary syphilis; endarteritis of the vasa vasorum results in luminal narrowing, decreased flow, and atrophy of the vessel wall. Results in a ‘tree-bark’ appearance of the aorta (Fig, 7.12)

Major complication is dilation of the aortic valve root, resulting in aortic valve insufficiency
Other complications include compression of mediastinal structures (e.g., airway or esophagus) and thrombosis/embolism.

Question 17

Abdominal Aortic Aneurysm

Answer 17

Balloon-like dilation of the abdominal aorta; usually arises below the renal arteries, but above the aortic bifurcation
Primarily due to atherosclerosis; classically seen in male smokers > 60 years old with hypertension
- Atherosclerosis increases the diffusion barrier to the media, resulting in atrophy and weakness of the vessel wrall.
- Presents as a pulsatile abdominal mass that grows with time
- Major complication is rupture, especially when > 5 cm in diameter; presents with triad of hypotension, pulsatile abdominal mass, and flank pain
- Other complications include compression of local structures (e.g., ureter) and thrombosis/embolism.

Question 18

Hemangioma

Answer 18

Benign tumor comprised of blood vessels
Commonly present at birth; often regresses during childhood

Most often involves skin and liver

Strawberry Hemangioma: Benign capillary hemangioma of infancy

• appears in first few weeks of life
• grows rapidly and regresses spontaneously at 5-8 yo

Cherry Hemangioma: benign capillary hemangioma of the elderly

• Does not regress
• frequency increases with age

Pyogenic granuloma

• polypoid capillary hemangioma that can ulcerate and bleed
• associated with trauma and pregnancy

Cystic hygroma

• cavernous lymphangioma of the neck
• associated with Tuner Syndrome (XO)

Question 19

Angiosarcoma

Answer 19

Malignant proliferation of endothelial cells; highly aggressive

• Common sites include skin, breast, and liver.
• Liver angiosarcoma is associated with exposure to polyvinyl chloride, arsenic, and Thorotrast.
• usually in elderly on sun exposed areas
• associated with radiation therapy and arsenic exposure
• very aggressive and difficult to resect due to delay in diagnosis

Question 20

Kaposi sarcoma

Answer 20

Low-grade malignant proliferation of endothelial cells; associated with HHV-8

Presents as purple patches, plaques, and nodules on the skin; may also involve visceral organs.

• Older Eastern European males—tumor remains localized to skin; treatment involves surgical removal.
• AIDS—tumor spreads early; treatment is antiretroviral agents (to boost immune system).
• Transplant recipients—tumor spreads early; treatment involves decreasing immunosuppression.

Question 21

Stable Angina

Answer 21

Stable angina is chest pain that arises with exertion or emotional stress.

Due to atherosclerosis of coronary arteries with > 70% stenosis; decreased blood flow is not able to meet the metabolic demands of the myocardium during exertion.
Represents reversible injury to myocytes (no necrosis)

Presents as chest pain (lasting < 20 minutes) that radiates to the left arm or jaw, diaphoresis, and shortness of breath
EKG shows ST-segment depression due to subendocardial ischemia.
Relieved by rest or nitroglycerin

Question 22

Unstable Angina

Answer 22

Unstable angina is chest pain that occurs at rest.

Usually due to rupture of an atherosclerotic plaque with thrombosis and incomplete occlusion of a coronary artery.

Represents reversible injury to myocytes (no necrosis)

EKG shows ST-segment depression due to subendocardial ischemia.

Relieved by nitroglycerin

High risk of progression to myocardial infarction

Question 23

Prinzmetel Angina

Answer 23

Prinzmetal angina is episodic chest pain unrelated to exertion.

Due to coronary artery vasospasm

Represents reversible injury to myocytes (no necrosis)

EKG shows ST-segment elevation due to transmural ischemia.

Relieved by nitroglycerin or calcium channel blockers

Question 24

Myocardial Infarction

Answer 24

Necrosis of cardiac myocytes

• Usually due to rupture of an atherosclerotic plaque with thrombosis and complete occlusion of a coronary artery
• Other causes include coronary artery vasospasm (due to Prinzmetal angina or cocaine use), emboli, and vasculitis (e.g., Kawasaki disease).
• Clinical features include severe, crushing chest pain (lasting > 20 minutes) that radiates to the left arm or jaw, diaphoresis, and dyspnea; symptoms are not relievedby nitroglycerin.

Infarction usually involves the left ventricle (LV); right ventricle (RV) and both atria

are generally spared.

• Occlusion of left anterior descending artery (LAD) leads to infarction of the anterior wall and anterior septum of the LV; LAD is the most commonly involved artery in MI (45% of cases).
• Occlusion of right coronary artery (RCA) leads to infarction of the posterior wall, posterior septum, and papillary muscles of the LV; RCA is the 2nd most commonly involved artery in MI.
• Occlusion of L. Circumflex leads to infarction of the lateral wall of the LV

EKG

• Intially will show ST depression due to subendocardial infarction
• Continued ischemia will show ST elevation if transmural ischemia

Labs

• Troponins rise 2-4 hrs after infarction, peak at 24 hrs. Return to normal by 7-10 day
• CK-MB rise at 6 hrs after infarction, Peak at 24 hours. Return to normal by 72 hrs.

Treatment

• ASA/ Heparin: limits thrombosis
• Supplemental O2: limits ischemia
• NItrates: vasodilate coronary arteries
• B-blocker: slows HR decrease oxygen demand
• ACEi: decreases LV dilation
• Fibrinolysis/ angioplasty: reperfusion (can cause contraction bands/ reperfusion injury)

Question 25

Sudden Cardiac Death

Answer 25

Unexpected death due to cardiac disease; occurs without symptoms or < 1 hour after symptoms arise

• Usually due to fatal ventricular arrhythmia
• Most common etiology is acute ischemia; 90% of patients have preexisting severe atherosclerosis.
• Less common causes include mitral valve prolapse, cardiomyopathy, and cocaine abuse.

Question 26

Left Sided Heart Failure

Answer 26

Causes include ischemia, hypertension, dilated cardiomyopathy, myocardial infarction, and restrictive cardiomyopathy.

• Clinical features are due to decreased forward perfusion and pulmonary congestion.
• Pulmonary congestion leads to pulmonary edema.
• Results in dyspnea, paroxysmal nocturnal dyspnea (due to increased venous return when lying llat), orthopnea, and crackles
• Small, congested capillaries may burst, leading to intraalveolar hemorrhage;marked by hemosiderin-laden macrophages (‘heart-failure’ cells)
• Decreased flow to kidneys leads to activation of renin-angiotensin system,

Fluid retention exacerbates CHF

• Mainstay of treatment is ACE inhibitor.

Question 27

Right Sided Heart Failure

Answer 27

Most commonly due to left-sided heart failure; other important causes include left-to-right shunt and chronic lung disease (cor pulmonale).

Clinical features are due to congestion.

• Jugular venous distension
• Painful hepatosplenomegaly with characteristic ‘nutmeg’ liver (Fig. 8.9); may lead to cardiac cirrhosis
• Dependent pitting edema (due to increased hydrostatic pressure)

Question 28

Ventricular Septal Defect

Answer 28

Defect in the septum that divides the right and left ventricles

• Most common congenital heart defect
• Associated with fetal alcohol syndrome
• left-to-right shunt; size of defect determines extent of shunting and age at presentation. Small defects are often asymptomatic; large defects can lead to Eisenmenger syndrome.

Treatment involves surgical closure; small defects may close spontaneously.

Question 29

Atrial Septal Defect

Answer 29

Defect in the septum that divides right and left atria;

• most common type is ostium secundum (90% of cases).
• Ostium primum type is associated with Down syndrome.
• Results in left-to-right shunt and split S2 on auscultation (increased blood in right heart delays closure of pulmonary valve)
• Paradoxical emboli are an important complication.

Question 30

Patent Ductus Arteriosus

Answer 30

Failure of ductus arteriosus to close; associated with congenital rubella
Results in left-to-right shunt between the aorta and the pulmonary artery

• During development, the ductus arteriosus normally shunts blood from the pulmonary artery to the aorta, bypassing the lungs.
• Asymptomatic at birth with holosystolic ‘machine-like’ murmur; may lead to Eisenmenger syndrome, resulting in lower extremity cyanosis
• Treatment involves indomethacin, which decreases PGE, resulting in PDA closure (PGE maintains patency of the ductus arteriosus).

Question 31

Tetralogy of Fallot

Answer 31

Characterized by

• stenosis of the right ventricular outflow tract
• right ventricular hypertrophy
• VSD
• an aorta that overrides the VSD

Right-to-left shunt leads to early cyanosis; degree of stenosis determines the extent of

shunting and cyanosis.

Patients learn to squat in response to a cyanotic spell; increased arterial resistance

decreases shunting and allows more blood to reach the lungs.

‘Boot-shaped’ heart on x-ray

Question 32

Transposition of Great Vessels

Answer 32

Characterized by pulmonary artery arising from the left ventricle and aorta arising

from the right ventricle

• Associated with maternal diabetes
• Presents with early cyanosis; pulmonary and systemic circuits do not mix.
• Creation of shunt (allowing blood to mix) after birth is required for survival. 2. PGE can be administered to maintain a PDA until definitive surgical repair is performed.
• Results in hypertrophy of the right ventricle and atrophy of the left ventricle

Question 33

Truncus Arteriosus

Answer 33

Characterized by a single large vessel arising from both ventricles

• Truncus fails to divide.
• Presents with early cyanosis; deoxygenated blood from right ventricle mixes with oxygenated blood from left ventricle before pulmonary and aortic circulations separate.

Question 34

Tricuspid Valve Atresia

Answer 34

Tricuspid valve orifice fails to develop; right ventricle is hypoplastic.

Often associated with ASD, resulting in a right-to-left shunt; presents with early

cyanosis

• Need ASD and VSD to survive

Question 35

Coarctation of the Aorta

Answer 35

Narrowing of the aorta (Fig. 8.11 A); classically divided into infantile and adult forms

Infantile form is associated with a PDA; coarctation lies after (distal to) the aortic arch, but before (proximal to) the PDA.

• Presents as lower extremity cyanosis in infants, often at birth
• Associated with Turner syndrome

Adult form is not associated with a PDA; coactation lies after (distal to) the aortic arch.

• Presents as hypertension in the upper extremities and hypotension with weak pulses in the lower extremities; classically discovered in adulthood
• Collateral circulation develops across the intercostal arteries; engorged arteries cause ‘notching’ of ribs on x-ray
• Associated with bicuspid aortic valve

Question 36

Acute Rheumatic Fever

Answer 36

Systemic complication of pharyngitis due to group A beta-hemolytic] **streptococci [Strep Pyogenes] **affects children 2-3 weeks after an episode of streptococcal pharyngitis (“strep throat”)

• Caused by molecular mimicry; bacterial M protein resembles proteins in human tissue.

Diagnosis is based on Jones criteria.

• Evidence of prior group A B-hemolytic streptococcal infection (e.g., elevated ASO or anti-DNase B titers) with the presence of major and minor criteria
• Minor criteria are nonspecific and include fever and elevated ESR.
• Major criteria
  
  • Migratory polyarthritis—swelling and pain in a large joint (e.g., wrist, knees, ankles) that resolves within days and “migrates” to involve another large joint
  • Pancarditis
    
    • Endocarditis—Mitral valve is involved more commonly than the aorticvalve. Characterized by small vegetations along lines of closure that leadto regurgitation (Fig, 8.12A)
    • Myocarditis with Aschoff bodies that are characterized by foci of chronic inflammation, reactive histiocytes with slender, wavy nuclei (Anitschkow cells), giant cells, and fibrinoid material (Fig. 8.I2B.C); myocarditis is the most common cause of death during the acute phase.
    • Pericarditis—leads to friction rub and chest pain
  • Subcutaneous nodules
  • Erythema marginatum—annular, nonpruritic rash with erythematousborders, commonly involving trunk and limbs
  • Sydenham chorea (rapid, involuntary muscle movements

Acute attack usually resolves, but may progress to chronic rheumatic heart disease; repeat exposure to group A B-hemolytic streptococci results in relapse of the acute phase and increases risk for chronic disease.

Question 37

Chronic Rheumatic Heart Disease

Answer 37

Valve scarring that arises as a consequence of rheumatic fever

• Results in stenosis with a classic ‘fish mouth’ appearance
• Almost always involves the mitral valve; leads to thickening of chordae tendineae and cusps
• Occasionally involves the aortic valve; leads to fusion of the commissures (Fig. 8.13)
• Other valves are less commonly involved.
• Complications include **infectious endocarditis. **

Question 38

Aortic Stenosis

Answer 38

Narrowing of the aortic valve orifice

• 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. A normal aortic valve has three cusps; fewer cusps results in increased “wear and tear” on each cusp.

May also arise as a consequence of chronic rheumatic valve disease; coexisting mitral stenosis and fusion ofthe aortic valve commissures distinguish rheumatic disease from “wear and tear.”

Cardiac compensation leads to a prolonged asymptomatic stage during which a systolic ejection click followed by a crescendo-decrescendo murmur is heard. Complications include

• Concentric left ventricular hypertrophy—may progress to cardiac failure
• Angina and syncope with exercise—Limited ability to increase blood flow across the stenotic valve leads to decreased perfusion of the myocardium and brain,
• Microangiopathic hemolytic anemia— RBCs are damaged (producing schistocytes) while crossing the calcified valve.

Treatment is valve replacement after onset of complications.

Question 39

Aortic Regurgitation

Answer 39

Backtlow of blood from the aorta into the left ventricle during diastole

Arises due to aortic root dilation (e.g., syphilitic aneurysm and aortic dissection) or valve damage (e.g.. infectious endocarditis); most common cause is isolated root dilation

Clinical features include

1. Early, blowing diastolic murmur
2. Hyperdynamic circulation due to increased pulse pressure

• Pulse pressure is the difference between systolic and diastolic pressures, it. Diastolic pressure decreases due to regurgitation, while systolic pressure increases due to increased stroke volume
• Presents with bounding pulse (water-hammer pulse), pulsating nail bed (Quincke pulse), and head bobbing

3. Results in LV dilation and eccentric hypertrophy (due to volume overload)

Treatment is valve replacement once LV dysfunction develops.

Question 40

Mitral Valve Prolapse

Answer 40

Ballooning of mitral valve into left atrium during systole.

Due to myxoid degeneration (accumulation of ground substance) of the valve, making it floppy

• Etiology is unknown; may be seen in Marfan syndrome or Ehlers-Danlossyndrome
• Presents with an incidental mid-systolic click followed by a regurgitation murmur;
• ** **Click and murmur become louder with squatting (increased systemic resistance decreases left ventricular emptying).

Complications are rare, but include infectious endocarditis, arrhythmia, and severe mitral regurgitation.

Treatment is valve replacement.

Question 41

Mitral Regurgitation

Answer 41

Reflux of blood from the left ventricle into the left atrium during systole

• Usually arises as a complication of mitral valve prolapse; other causes include LV dilatation (e.g., left-sided cardiac failure), infective endocarditis, acute rheumatic heart disease, and papillary muscle rupture after a myocardial infarction.

Clinical features

• Holosystolic “blowing” murmur; louder with squatting (increased systemic resistance decreases left ventricular emptying) and expiration (increased return to left atrium)

Results in volume overload and left-sided heart failure

Question 42

Mitral Stenosis

Answer 42

Narrowing of the mitral valve orifice

• Usually due to chronic rheumatic valve disease

Clinical features

• Opening snap followed by diastolic rumble
• Volume overload leads to dilatation of the left atrium, resulting in
  
  • Pulmonary congestion with edema and alveolar hemorrhage
  • Pulmonary hypertension and eventual right-sided heart failure
  • Atrial fibrillation with associated risk for mural thrombi

Question 43

Endocarditis

Answer 43

Inflammation of endocardium that lines the surface of cardiac valves; usually due to bacterial infection.

• Streptococcus viridans is the most common overall cause. It is a low-virulence organism that infects previously damaged valves (e.g., chronic rheumatic heart disease and mitral valve prolapse). Results in small vegetations that do not destroy the valve (subacute endocarditis). Undamaged endocardial surface develops thrombotic vegetations (platelets and fibrin).Transient bacteremia leads to trapping of bacteria in the vegetations; prophylactic antibiotics decrease risk of endocarditis.
• Staphylococcus aureus is the most common cause in (V drug abusers.
  
  • High-virulence organism that infects normal valves, most commonly the tricuspid.
  • Results in large vegetations that destroy the valve (acute endocarditis. Fig. 8.17)
• Staphylococcus epidermidis is associated with endocarditis of prosthetic valves.
• Streptococcus bovis is associated with endocarditis in patients with underlying colorectal carcinoma.
• HACEK organisms (Haemophilus, ActinobaciUus, Cardiobacterium, Eikenella, Kingella) are associated with endocarditis with negative blood cultures.

Clinical features of bacterial endocarditis include

• Fever—due to bacteremia
• Murmur—due to vegetations on heart valve
• Janeway lesions (erythematous nontender lesions on palms and soles).
• Oslernodes (tender lesions on fingers or toes), and splinter hemorrhages in nail bed due to embolization of septic vegetations
• Anemia of chronic disease—due to chronic inflammation

Libman-Sacks endocarditis is due to sterile vegetations that arise in association with SLE. Vegetations are present on the surface and undersurface of the mitral valve and result in mitral regurgitation.

Question 44

Dilated Cardiomyopathy

Answer 44

Dilation of all four chambers of the heart (Fig. 8.18); most common form of cardiomyopathy

• Results in systolic dysfunction (ventricles cannot pump), leading to biventricular CHF; complications include mitral and tricuspid valve regurgitation and arrhythmia.
• Most commonly idiopathic; other causes include
  
  • Genetic mutation (usually autosomal dominant)
  • Myocarditis (usually due to coxsackie A or B)—characterized by a lymphocytic infiltrate in the myocardium (Fig. 8.19); results in chest pain, arrhythmia with sudden death, or heart failure. Dilated cardiomyopathy is a late complication.
  • Alcohol abuse
  • Drugs (e.g., doxorubicin)
  • Pregnancy—seen during late pregnancy or soon (weeks to months) after childbirth

ABCCD: Alcohol, Beriberi, Coxsackie B, chronic Cocaine use, Chagas Disease, Doxorubicin toxicity

Treatment is heart transplant.

Question 45

Hypertrophic Cardiomyopathy

Answer 45

Massive hypertrophy of the left ventricle

• Usually due to genetic mutations in sarcomere proteins; most common form is autosomal dominant,

Clinical features include

• Decreased cardiac output—Left ventricular hypertrophy leads to diastolic dysfunction (ventricle cannot fill).
• Sudden death due to ventricular arrhythmias; hypertrophic cardiomyopathy is a common cause of sudden death in young athletes.
• Syncope with exercise—Subaortic hypertrophy of the ventricular septum results in functional aortic stenosis.

Biopsy shows myofiber hypertrophy with disarray (Fig. 8.20).

Question 46

Restrictive Cardiomyopathy

Answer 46

Decreased compliance of the ventricular endomvocardium that restricts filling during diastole

• Causes include amyloidosis, sarcoidosis, hemochromatosis, endocardial fibroelastosis (children. Fig. 8.21), and Ioefller syndrome (endomyocardial fibrosis with an eosinophilic infiltrate and eosinophilia).
• Presents as congestive heart failure; classic finding is low-voltage EKG with diminished QRS amplitude.

Question 47

Myxoma

Answer 47

Benign mesenchymal tumor with a gelatinous appearance and abundant ground substance on histology

• Most common primary cardiac tumor in adults
• Usually forms a pedunculated mass in the left atrium that causes syncope due to **obstruction of the mitral valve **

Question 48

Rhabdomyoma

Answer 48

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

Question 49

Cardiac Metastasis

Answer 49

Metastatic tumors are more common in the heart than primary tumors.

• Common metastases to the heart include breast and lung carcinoma, melanoma, and lymphoma.
• Most commonly involve the pericardium, resulting in a **pericardial effusion **

Question 50

Torsades de pointes

Answer 50

Polymorphic ventricular tachycardia, characterized by shifting sinusoidal waveforms on ECG; can progress to ventricular fibrillation.

Long QT interval predisposes to torsades de pointes.

Caused by drugs,K+, Mg2+, other abnormalities.

Treatment includes magnesium sulfate.

Some Risky Meds Can Prolong QT:

Sotalol, Risperidone (antipsychotics), Macrolides, Chloroquine, Protease inhibitors, Quinidine (class Ia; also class III), Thiazides

Question 51

Congenital long QT syndrome

Answer 51

Inherited disorder of myocardial repolarization, typically due to ion channel defects; risk
of sudden cardiac death due to torsades de pointes.

Includes:

• ƒ Romano-Ward syndrome—autosomal dominant, pure cardiac phenotype (no deafness).
• ƒ Jervell and Lange-Nielsen syndrome— autosomal recessive, _sensorineural deafness. _

Question 52

Wolff-Parkinson-White syndrome

Answer 52

Most common type of ventricular pre-excitation syndrome.

Abnormal fast accessory conduction pathway from atria to ventricle (bundle of Kent) bypasses the rate-slowing AV node.

As a result, ventricles begin to partially depolarize earlier, giving rise to characteristic delta wave with shortened PR interval on ECG. May result in reentry circuitŽ–>_supraventricular tachycardia. _

Question 53

Atrial fibrillation

Answer 53

Chaotic and erratic baseline (irregularly irregular) with no discrete P waves in between irregularly spaced QRS complexes.

Can result in atrial stasis and lead to thromboembolic stroke.

Treatment includes rate control, anticoagulation, and possible pharmacological or electrical cardioversion.

Question 54

Atrial flutter

Answer 54

A rapid succession of identical, back-to-back atrial depolarization waves. The identical appearance accounts for the “sawtooth” appearance of the flutter waves.

Management:

Pharmacologic conversion to sinus rhythm: class IA, IC, or III antiarrhythmics.

Rate control: β-blocker or calcium channel blocker.

Definitive treatment is catheter ablation.

Question 55

Ventricular Fibrillation

Answer 55

A completely erratic rhythm with no identifiable waves. Fatal arrhythmia without immediate CPR and defibrillation.

Question 56

AV block

Answer 56

1st degree: The PR interval is prolonged (> 200 msec). Benign and asymptomatic. No treatment required.

2nd degree:

• Mobitz type I (Wenckebach) : Progressive lengthening of the PR interval until a beat is “dropped” (a P wave not followed by a QRS complex). Usually asymptomatic.
• Mibitz type 2: Dropped beats that are not preceded by a change in the length of the PR interval (as in type I). It is often found as 2:1 block, where there are 2 or more P waves to 1 QRS response. May progress to 3rd-degree block. Often treated with pacemaker.
  
  • EKG: no QRS after P

3rd degree block: (complete) The atria and ventricles beat independently of each other. Both P waves and QRS complexes are present, although the P waves bear no relation to the QRS complexes. The atrial rate is faster than the ventricular rate. Usually treated with pacemaker.

• Lyme disease can result in 3rd-degree heart block.