Cardiovascular Flashcards

0
Q

What are the three shunts in fetal circulation?

A
1) Ductus venosus
Umbilical vein (oxygenated) --> IVC

2) Foramen ovale
RA (oxygenated) –> LA

3) Ductus arteriosus
Pulmonary artery (deoxygenated from SVC) --> Aorta (after the great vessels)
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1
Q

Where does fetal erythropoiesis occur?

A

“Young Liver Synthesizes Blood”

Yolk sac (3-10 wk)
Liver (6 wk-birth)
Spleen (15-30 wk)
Bone marrow (22 wk+)

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2
Q

What is used to keep a PDA open?

To close it?

A

PGE keeeeeps it open

Indomethacin closes it

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3
Q

What does the umbilical vein become?

A

Ligamentum teres hepatis

within falciform ligament

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4
Q

What do the umbilical arteries become?

A

Medial umbilical ligaments

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5
Q

What does the ductus arteriosus become?

A

Ligamentum arteriosum

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6
Q

What does the ductus venosus become?

A

Ligamentum venosum

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7
Q

What does the foramen ovale become?

A

Fossa ovale

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8
Q

What does the urachus become?

A

Median umbilical ligament

Urachus is part of the allantoic duct (portion between bladder & umbilicus)

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9
Q

What does the notochord become?

A

Nucleus pulposus of intervertebral disc

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10
Q

What does it mean to be right heart dominant vs. left?

A

Right dominant (85%) - the posterior descending artery arises from the RCA

Left dominant (8%) - the PD arises from the Left circumflex

Codominant (7%)

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11
Q

What heart chamber composes the back of the heart?

What can be seen with pathology?

A

The LA is the most posterior chamber. Enlargement can cause dysphagia (esophageal compression) or hoarseness (recurrent laryngeal)

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12
Q

Myocardial infarction:
What leads will show alterations?
What artery is infarcted?
Left lateral wall

A

Leads I, AVL, V5, V6

LCX or LCA infarction

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13
Q

Myocardial infarction:
What leads will show alterations?
What artery is infarcted?
Anterior

A

Leads: V2-V4

LAD

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14
Q

Myocardial infarction:
What leads will show alterations?
What artery is infarcted?
Septal

A

Leads: V1,V2

LAD

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15
Q

Myocardial infarction:
What leads will show alterations?
What artery is infarcted?
Inferior

A

Leads: II,III,AVF

PDA or RCA

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16
Q

What are the equations for Cardiac Output?

A

CO = Stroke Volume * HR

CO =
O2 consumption rate)/(arterial O2 content - venous O2 content

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17
Q

What are the equations for mean arterial pressure?

A

MAP = (2/3)Diastolic + (1/3)Systolic

MAP = CO x TPR

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18
Q

What factors increase myocardial O2 consumption?

A

^Afterload
^Contractility
^HR
^Heart size (wall tension)

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19
Q

How does blood pH affect potassium levels?

A

Potassium moves the opposite direction of protons across cell membranes in order to maintain charge.Thus:

Acidosis –> hyperkalemia
Alkalosis –> hypokalemia

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20
Q

What effect does insulin have on potassium?

A

INsulin causes K+ shift INto cells.

This is why DKA pts are hyperkalemic at first but may become hypokalemic with treatment. (Also because acidosis –> hyperkalemia).

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21
Q

How does acidosis decrease contractility?

A

H+ shifts into cardiac cells, so K+ shifts out –> hyperpolarization of the membrane

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22
Q

How are preload and afterload affected by dilating drugs?

A

vEnodilators decrease prEload

vAsodilators decrease Afterload

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23
Q

What can decrease contractility?

A
Beta blockade
CHF
Acidosis
Hypoxia/Hypercapnia
Non-dihydropyridine CCB's
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24
Q

What is the equation for ejection fraction?

What is a normal ejection fraction?

A

EF = (EDV - ESV)/EDV

Normal is >55%

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25
Q

What portion of the vasculature accounts for most of the resistance to flow?

A

Arterioles

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26
Q

What is the total resistance of vessels in series?

In parallel?

A

Series:
Total = R1 + R2 + R3. . .

Parallel:
1/Total = 1/R1 + 1/R2 + 1/R3. . .

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27
Q

What factors determine resistance?

A

Viscosity & vessel length increase resistance

Radius decreases resistance

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28
Q

What are the waves on a jugular venous pulse tracing?

A
a = RA contraction
c = RV contraction (valve bulges backward)
v = RA filling against closed tricuspid
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29
Q

What causes the dicrotic notch seen on aortic pressure tracings?

A

Transient backward flow back into the LV, which causes closure of the valve. The elastic recoil of the aorta can then exert its effects, causing an increase in pressure.

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30
Q

When is an S3 heard?

A

Normal in children & pregnancy

Otherwise indicates ^filling pressures and/or a dilated LV.

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31
Q

What causes wide splitting of S2?

A

Wide splitting: varies with respiration but is always wider than expected.

Caused by pulmonic stenosis or RBBB

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32
Q

What causes fixed splitting of the S2 heart sound?

A

ASD is the only etiology

Left to right shunt causes splitting all of the time

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33
Q

What causes paradoxical splitting?

A

Inspiration: They close together
Expiration: P2 closes before A2

Aortic stenosis & LBBB

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34
Q

Where is a HOCM murmur heard best?

A

Systolic murmur at the left sternal border (3rd intercostal space)

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35
Q

Where are aortic & pulmonic regurgitation heard best?

A

Diastolic murmurs at the left sternal border (3rd intercostal space)

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36
Q

What can be heard with an ASD?

Where?

A

Pulmonary flow murmur & diastolic rumble heard best at pulmonic area.

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37
Q

What effect does inspiration have on murmurs?

Expiration?

A

Inspiration –> ^intensity of right heart sounds

Expiration –> ^intensity of left heart sounds

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38
Q

What effect does the hand grip technique have on murmurs?

A

^systemic vascular resistance

Louder: AR, MR, VSD, MVP
Softer: AS, HOCM

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39
Q

What effect does valsalva have on murmurs?

A

Decreases venous return

Louder: MVP, HOCM
Softer: Most murmurs

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40
Q

What effect does rapid squatting have on murmurs?

A

Increases venous return

Softer: MVP, HOCM

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41
Q

What is heard with mitral/tricuspid regurgitation?

A

Mitral - Holosystolic blowing murmur loudest at apex & radiates to axilla.

Tricuspid - Holosystolic blowing murmur loudest at tricuspid area & radiates to RSB.

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42
Q

How does aortic stenosis sound?

What else is seen?

A

Systolic ejection click followed by crescendo-decrescendo murmur. Heard best at the aortic area & radiates to carotids.

“Pulsus parvus et tardus” = weak pulses w/ a delayed peak

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43
Q

What causes aortic stenosis?

What are the symptoms?

A

Causes:
Bicuspid aortic valve
Calcific aortic stenosis

Symptoms:
Syncope
Angina
Dyspnea on exertion

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44
Q

How does a VSD sound?

What effect does size of the VSD have on the sound?

A

Holosystolic, harsh murmur loudest at tricuspid area.

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45
Q

How does mitral valve prolapse sound?

A

Midsystolic click then crescendo murmur. Heard bast at the apex.

Enhanced by decreased venous return (standing, valsalva).

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46
Q

What can cause mitral valve prolapse?

A

Often associated with young adult women. Caused by:
Myxomatous degeneration
Rheumatic fever
Chordae rupture

It ^susceptibility to infective endocarditis.

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47
Q

What does aortic regurgitation sound like?

What else can be seen?

A

Immediate blowing diastolic decrescendo murmur. Heard best at LSB.

Wide “water hammer” pulse pressures & head bobbing can also be seen.

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48
Q

What can cause aortic regurgitation?

A

Aortic root dilation (syphilis or idiopathic)
Bicuspid aortic valve
Endocarditis
Rheumatic fever (mitral always involved)

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49
Q

How does mitral stenosis sound?

A

Diastolic opening snap, followed by rumbling late diastolic murmur.

99% are due to rheumatic fever

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50
Q

What does a PDA sound like?

What causes it?

A

Continuous “machinery” murmur heard best at infraclavicular area.

Caused by congenital rubella or prematurity.

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51
Q

What is the best prognostic indicator of mitral stenosis?

Aortic stenosis?

A

Time to opening snap (MS) or ejection click (AS)

Mitral: Early opening snap –> more severe

Aorta: Early ejection click –> less severe

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52
Q

What channels are responsible for the slow diastolic depolarization seen in the SA & AV node?

A

If (funny) channels –> Na+ flows into the cell slowly

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53
Q

What are the resting membrane potentials of cardiac pacemaker cells?
Myocytes?

A

Pacemaker cells = -70 mV

Myocytes & His-Purkinje = -90 mV

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54
Q

What can cause the appearance of a U wave?

A

Hypokalemia

Bradycardia

55
Q

What ECG finding may lead to Torsades de pointes?

A

Anything that prolongs the QT interval.

56
Q

What is seen in Jervell and Lange-Neilsen syndrome?

A

Autosomal recessive syndrome causing congenital QT elongation & deafness

57
Q

What can cause transient isolated atrial fibrillation?

A

Binge EtOH consumption (“holiday heart”)
Sympathetic tone
Pericarditis

58
Q

What is the path of the aortic arch baroreceptors & the carotid sinus baroreceptors?

A

Aortic arch –> vagus nerve –> nucleus solitarius (medulla)

Carotid sinus –> glossopharyngeal nerve –> nucleus solitarius

Both of them show decreased firing rates in response to hypotension. The carotid body can respond to both increases or decreases in BP.

59
Q

What is the Cushing reaction?

What causes it?

A

Cushing reaction:
Hypertension
Bradycardia
Respiratory depression

Caused by ^ICP –> arteriole constriction –> cerebral ischemia –> compensatory hypertension –> baroreceptors cause bradycardia

60
Q

What do the central & peripheral chemoreceptors respond to?

A

Central - pH & PCO2

Peripheral (carotid & aortic bodies) - PO2 (<60 mmHg)

61
Q

What are normal pulmonary artery pressures?

A

25/10

Pulmonary capillary wedge pressure < 12

62
Q

What are normal LV & RV pressures?

A

LV = 130/10

RV = 25/5

63
Q

How is the heart autoregulated?

A

Local metabolites (CO2, Adenosine, NO)

64
Q

How is the brain autoregulated?

A

CO2 –> vasodilation

65
Q

How is the kidney autoregulated?

A

Myogenic & tubuloglomerular feedback

66
Q

How is skeletal muscle autoregulated?

A

Local metabolites (lactate, adenosine, K+)

67
Q

What congenital heart diseases cause early cyanosis?

A

5 T’s:

Tetralogy
Transposition
Truncus
Tricuspid
TAPVR
68
Q

What causes late cyanosis?

What is the mechanism?

A

Late cyanosis = Eisenmenger’s Syndrome

Uncorrected ASD, VSD, or PDA (L–>R shunt) causes eventual pulmonary vascular hypertrophy –> pulmonary HTN –> reversal of shunt –> late cyanosis, clubbing, & polycythemia.

69
Q

What is the most common congenital heart defect?

A

VSD

Associated with fetal alcohol syndrome.

70
Q

What type of ASD is most common?

A

Ostium secundum (90%)

Ostium primum type is found in Down Syndrome pts

71
Q

What is seen with ASD?

A

Fixed splitting
Paradoxical emboli
Late cyanosis

72
Q

What type of cyanosis is seen with a PDA?

A

Late cyanosis in the LOWER EXTREMITIES

PDA comes off after the great vessels

73
Q

What is seen in Persistent Truncus Arteriosus?

A

Truncus arteriosus does not divide into aorta & pulmonary trunk. Most patients have a VSD as well.

Presents with early cyanosis.

74
Q

What is seen with tricuspid atresia?

A

Absence of tricuspid valve (it’s sealed shut) & hypoplastic RV. Requires both an ASD & VSD for survival.

Presents with early cyanosis.

75
Q

What is seen with TAPVR?

A

Total Anomalous Pulmonary Venous Return

Pulmonary veins drain into right heart circulation. ASD (or rarely PDA) is required to sustain life. Presents with early cyanosis.

76
Q

What is seen in Tetralogy of Fallot?

A

1) Pulmonary infundibular stenosis (prognostic)
2) RVH (boot shaped heart on CXR)
3) VSD
4) Overriding aorta (overrides the VSD)

Presents with early cyanosis (pulmonic stenosis forces blood R–>L across the VSD).

77
Q

What congenital heart defect is associated with tet spells?

A

tet spells = cyanotic spells seen in Tetralogy of Fallot

Patients learn to squat –> ^TPR –> decreased R–>L shunt

78
Q

What causes transposition of the great vessels?

A

Failure of aorticopulmonary septum to spiral (associated with maternal diabetes) –> Aorta comes off RV & pulmonary trunk comes off LV –> Pulmonary & systemic circulations are separate

ASD, VSD, or PDA required for survival.

79
Q

What is the treatment for Transposition of the Great Vessels?

A

Keep the PDA open (PGE) until surgery can be performed

80
Q

What is seen with infantile coarctation of the aorta?

What other condition is it associated with?

A

Coarctation lies proximal to the PDA (preductal). Presents with early lower extremity cyanosis & weak femoral pulses.

It is associated with Turner syndrome.

INfantile = IN close to the heart

81
Q

What is seen in adult coarctation of the aorta?

What other condition is it associated with?

A

Coarctation is distal to the ligamentum arteriosum (postductal). Presents with:
Notching of the ribs (collateral circulation from great vessels)
HTN in UE’s & weak pulses in LE’s

It is associated with bicuspid aortic valve.

82
Q
What congenital cardiac defects are seen with the following conditions?
22q11 syndromes
Down syndrome
Congenital rubella
Turner syndrome
Marfan's syndrome
Maternal diabetes
A

22q11 syndromes –> Persistent truncus arteriosus, ToF
Down syndrome –> ASD (ostium primum), VSD, cushion defect
Congenital rubella –> PDA
Turner syndrome –> Preductal coarctation of aorta
Marfan’s syndrome –> Aortic regurgitation, dissection
Maternal diabetes –> Transposition of great vessels
Fetal alcohol syndrome –> VSD

83
Q

What is the cutoff for HTN?

Malignant HTN?

A

HTN = 140/90

Malignant = 180/120

84
Q

What are the signs of hyperlipidemia?

A

Atheromas
Xanthomas (xanthelasma - on/around the eye)
Tendinous xanthomas (Achilles is common)
Corneal arcus (nonspecific)

85
Q

What are the 3 types of arteriosclerosis?

A

Monckeberg Medial Calcific Sclerosis - calcification of the media. Can be seen on x-ray

Arteriolosclerosis - hyaline (HTN & DM) & hyperplastic (malignant HTN)

Atherosclerosis - atheromas within the intima

86
Q

What are the types of arteriolosclerosis & their causes?

A

Hyaline - caused by essential HTN or diabetes. Pink amorphous hyaline material

Hyperplastic - caused by malignant HTN. “Onion skin” appearance

87
Q

What are the risk factors for atherosclerosis?

A

Modifiable: Smoking, Hypertension, Hyperlipidemia, Diabetes

Non-modifiable:
Age
Gender (^men & postmenopausal women)
Family history

88
Q

What is the pathogenesis of an atheroma?

A

1) Damage to endothelium allows lipid entry into intima
2) Lipids are oxidized and consumed by macs –> foam cells
3) Inflammation & healing with fibrosis & smooth muscle cell migration

The result is an atheroma composed of a necrotic lipid core & a fibromuscular cap.

89
Q

Where is atherosclerosis found in the body?

A

Abdominal aorta > Coronary > Popliteal > Carotid

90
Q

What causes AAA?

Where are they found?

A

Atherosclerosis –> prevents oxygenation of wall
Most frequently found in hypertensive male smokers > 50

They are usually infrarenal

91
Q

How does a ruptured AAA present?

A

Hypotension
Pulsatile abdominal mass
Flank pain

92
Q

What % of a vessel must be blocked to be symptomatic?

A

70%+

93
Q

What are the causes of thoracic aortic aneurysm?

A

Tertiary syphilis (tree bark appearance)
Cystic medial necrosis (Marfan’s)
Hypertension

Can lead to Aortic Regurgitation

94
Q

What causes aortic dissection?

A

Hypertension
Bicuspid aortic valve
Cystic medial necrosis (Marfan’s, Ehlers-Danlos)

95
Q

How does aortic dissection present?

What are the complications?

A

Tearing chest pain that radiates to the back. Widened mediastinum on CXR.

Complications:
Cardiac tamponade (most common COD)
Rupture
Death

96
Q

What is seen on ECG with the 3 types of angina?

A

Stable & Unstable –> ST depression

Prinzmetal –> ST elevation

97
Q

What are the causes of the 3 types of angina?

A

Stable - atherosclerosis –> ischemia with exertion

Prinzmetal’s - coronary artery vasospasm (at rest)

Stable - thrombosis w/ incomplete arterial occlusion (at rest)

98
Q

What is coronary steal?

A

When there is ischemic heart disease present, administration of vasodilators can cause increased perfusion to the healthier tissues, leaving the ischemic tissue even more ischemic.

99
Q

What are the causes of sudden cardiac death?

A

90% fatal arrhythmia secondary to CAD
HOCM (kids)
Mitral valve prolapse
Cocaine use

100
Q

What are the most commonly thrombosed coronary arteries?

A

LAD > RCA > LCX

101
Q

<4h post-MI
What is seen grossly?
What is seen microscopically?
What are the possible complications?

A

Gross - normal

Microscopic - normal

Risk - Arrhythmia, CHF, Cardiogenic shock

102
Q

4-12h post-MI
What is seen grossly?
What is seen microscopically?
What are the possible complications?

A

Gross - Darkly mottled infarct

Microscopic - Early coagulative necrosis (no nuclei)

Complications: Arrhythmia

103
Q

12-24h post-MI
What is seen grossly?
What is seen microscopically?
What are the possible complications?

A

Gross: Dark mottling of infarct

Microscopic:
Contraction bands (perpendicular to fibers)
Beginning of PMN infiltration

Complications: Arrhythmia

104
Q

1-3 days post-MI
What is seen grossly?
What is seen microscopically?
What are the possible complications?

A

Gross: Hyperemia

Microscopic:
Coagulative necrosis
Dense PMN infiltration

Complications:
Fibrinous pericarditis (seen only with transmural infarct)
105
Q

3 days to 2 weeks post-MI
What is seen grossly?
What is seen microscopically?
What are the possible complications?

A

Gross: Central yellow-brown softening w/ hyperemic border

Microscopic:
Macrophage infiltration w/ granulation tissue at the margins

Complications:
Free wall rupture –> tamponade
Papillary muscle rupture (RCA infarct; mitral regurgitation)
Interventricular septum rupture
Aneurysm (Mural thrombi; risk greatest at 1 week)

106
Q

2 weeks to several months post-MI
What is seen grossly?
What is seen microscopically?
What are the possible complications?

A

Gross: Gray-white scar (Type I collagen)

Microscopic: Collagen

Complications:
Dressler’s syndrome (autoimmune fibrinous pericarditis; 6-8 wks)

107
Q

How is MI diagnosed?

A

ECG is the gold standard within the first 6h
Troponin I - rises after 4h; specific
CK-MB - found in myocardium & skeletal muscle; useful in diagnosing reinfarction bc returns to baseline in 48h

108
Q

What causes contraction band necrosis?

A

When a cardiac infarct is reperfused, Ca2+ enters myocytes –> contraction.

109
Q

What are the causes of dilated cardiomyopathy?

A

ABCCCDE:

Alcohol abuse
Ber1Ber1 (wet)
Coxsackie B myocarditis
Chagas' disease
Cocaine (chronic)
Doxorubicin
Expectancy (pregnancy)
110
Q

What type of hypertrophy is seen in dilated vs hypertrophic cardiomyopathy?

A

Dilated = eccentric hypertrophy (sarcomeres added in series)

Hypertrophic = asymmetric concentric hypertrophy (in parallel)

111
Q

What is the cause of hypertrophic cardiomyopathy?

A

Most cases are familial.
Autosomal dominant sarcomere mutation (myosin heavy chain)
Associated with Friedrich’s Ataxia.

112
Q

What is the treatment for HOCM?

A

Beta blockers or non-dihydropyridine CCB’s

113
Q

What is the treatment for dilated cardiomyopathy?

A
Salt restriction
ACE inhibitors
Diuretics
Digoxin
Transplant
114
Q

What can cause restrictive cardiomyopathy?

A
Amyloidosis
Sarcoidosis
Endocardial fibroelastosis (children)
Loffler's syndrome (endomyocardial fibrosis w/ eosinophils)
Hemochromatosis (can cause dilated or restrictive)
115
Q

What CCB’s are cardioselective?

Vascular?

A

Cardioselective - Verapamil, Diltiazem

Vascular SM - Amlodipine, Nifedipine

116
Q

What toxicities are seen with CCB’s?

A

Peripheral edema
Flushing
Cardiac depression/AV block
Gingival hyperplasia (Verapamil)

117
Q

What is Hydralazine used for?

A

Vasodilates arterioles > veins –> afterload reduction

Used for:
HTN in pregnancy (with methyldopa)
CHF

Often used with a beta-blocker to prevent reflex tachycardia

118
Q

What toxicities are seen with hydralazine?

A

Reflex tachycardia (contraindicated in angina/CAD)
Fluid retention
Drug-induced lupus

119
Q

What drugs are used to treat malgnant HTN?

What are their mechanisms?

A

Nitroprusside - NO release –> vasodilation (slightly V > A)

Fenoldopam - D1 agonist –> vasodilation of all capillary beds –> decreased BP & natriuresis

120
Q

What are nitrates used for?

What side-effects are seen?

A

Nitroglycerin & isosorbide dinitrate

Used for angina or pulmonary edema.

Side effects - Reflex tachycardia, hypotension, flushing, HA

121
Q

What is Monday disease?

A

People exposed to occupational nitrates have tolerance to them during the week then lose the tolerance over the weekend. So on Monday’s, they get tachycardia, dizziness, & HA.

122
Q

What is the mechanism of statins?

What are their toxicities?

A

Statins inhibit HMG-CoA Reductase. Also an ^ in peripheral LDLR is seen.

Toxicities:
Hepatotoxic
Rhabdomyolysis

123
Q

What is the mechanism of Niacin in lowering blood lipids?

What are the toxicities?

A

Inhibits lipolysis in adipose tissue & reduces VLDL secretion by the liver. Increases HDL substantially.

Toxicities:
Facial flushing
Hyperglycemia
Hyperuricemia

124
Q

What is the mechanism of Ezetimibe?

What toxicities are seen?

A

Ezetimibe blocks cholesterol reabsorption in the intestine.

Toxicities:
Rare ^LFT’s
Diarrhea

125
Q

What is the mechanism of Fibrates?

What toxicities are seen?

A

Fibrates upregulate Lipoprotein lipase –> ^TG clearance
They are most effective for lowering Triglycerides

Gemfibrozil, Fenofibrate, Clofibrate, Bezafibrate

Toxicities:
Myositis
Hepatotoxic
Cholesterol gallstones
Don't use w/ statins, if you must - use Fenofibrate
126
Q

What is the mechanism of digoxin?

What are its uses?

A

Inhibits Na+/K+ ATPase –> Impaired Na+/Ca2+ exchanger –> increased intracellular Ca2+ –> positive inotropy
Also stimulates vagus nerve to decrease HR

Used for:
CHF (inotropy)
A-fib (slows AV nodal conduction)

127
Q

What toxicities are seen with Digoxin?

A

Cholinergic - N/V, diarrhea, blurred yellow vision
ECG - ^PR, short QT, AV block, ST scooping, T inversion
Hyperkalemia

Factors causing toxicity:
Renal failure
Hypokalemia (Digoxin binds K+ site on ATPase)
Quinidine

128
Q

What are the classes of antiarrhythmics?

A

Class I = Na+ channel blockers
Class II = Beta blockers
Class III = K+ channel blockers
Class IV = Ca2+ channel blockers

129
Q

What are the Class Ia antiarrhythmics?
What is their effect?
What are their toxicities?

A

Quinidine, Procainamide, Disopyramide

They ^AP duration, effective refractory period, & QT interval

Toxicity:
Quinidine - Cinchonism (HA, tinnitus)
Procainamide - drug induced SLE
Disopyramide - CHF
Torsades
130
Q

What are the Class Ib antiarrhythmics?
What is their effect?
What are their toxicities?

A

Lidocaine, Mexiletine, Tocainide

They decrease AP duration in ischemic tissue. Useful in acute ischemic arrhythmias & Digoxin toxicity.

Toxicity:
Cardiac depression
CNS stimulation/depression

131
Q

What are the Class Ic antiarrhythmics?
What is their effect?
What are their toxicities?

A

Flecainide, Propafenone

No affect on AP duration. Only used as a last resort for intractable Vtach, Vfib, or SVT and only if heart is structurally normal.

Toxicity:
Pro-arrhythmic
^^AV node refractory period

132
Q

What arrhythmias are beta blockers (Class II antiarrhythmics) used to treat?

A

Vtach
SVT
Afib/flutter w/ RVR

133
Q

What are the Class III antiarrhythmics?
What is their effect?
What are their toxicities?

A

AIDS: Amiodarone, Ibutilide, Dofetilide, Sotalol

^AP duration & refractory period

Toxicity:
Sotalol - torsades, excessive beta block
Ibutilide - torsades
Amiodarone:
Pulmonary fibrosis, hepatotoxicity, hypo/hyperthyroidism
(must check LFT’s, PFT’s, & TFT’s when using amiodarone)
Corneal/skin deposits –> photodermatitis
Neurologic effects
Heart block

134
Q

What is adenosine used for?
What is its mechanism?
What are its toxicities?

A

It is the drug of choice in treating SVT. Only lasts for ~15 seconds.

Adenosine causes K+ release from cells –> hyperpolarization
Its effects are blocked by Theophylline & Caffeine

Toxicities: Flushing, hypotension, chest pain

135
Q

What is the use of magnesium as an antiarrhythmic agent?

A

It is used in torsades & digoxin toxicity.

136
Q

What is seen in hyperkalemia on ECG?

A

U waves
Peaked T waves
Arrhythmia