Usmle Step 1 2010: Cardiovascular System

Front 1

What are three structures inside the Carotid Sheath?

Back 1

Internal Jugular Vein (lateral)
Common Carotid Artery (Medial)
Vagus Nerve (Posterior)

Front 2

Occlusion of this coronary artery will cause atypical chest pain, epigastric pain similar to GERD.

Back 2

Right Coronary Artery

Front 3

In 80% of cases, the SA node and AV node are supplied by which blood vessel?

Back 3

Right Coronary Artery

Front 4

Which coronary artery most commonly occluded? And this vessel supplies what portion of the heart?

Back 4

LAD; supplying the anterior ventricular septum.

Front 5

Left atrial enlargement can cause dysphagia and hoarsness. Explain.

Back 5

Compression of esophageal nerve (dysphagia) and compression of the recurrent laryngeal nerve, a branch of the vagus (hoarseness)

Front 6

Make 2 equations for Mean Arterial Pressure using the following: 1) Cardiac Output, TPR
2) Systolic pressure, Diastolic pressure

Back 6

1) MAP = CO x TPR
2) MAP = 2/3 Diastolic pressure + 1/3 Systolic pressure

Front 7

In a healthy individual, ___ is an index of arteriolar resistance

Back 7

TPR

Front 8

How do catecholamines increase Contractility and Stroke Volume?

Back 8

Increases activity of Ca++ pump in the sarcoplasmic reticulum.

Front 9

How does a low extracellular Na+ cause increased contractility and Stroke volume?

Back 9

Decreased activity of the Na+/Ca++ exchanger

Front 10

What is preload?

Back 10

ventricular end diastolic volume

Front 11

What is Afterload?

Back 11

Mean arterial pressure (proportional to peripheral resistance);

It is essentially the force needed to eject blood from the left ventricle into the aorta

Front 12

Patient complaining of retrosternal chest pain on exertion. Nitrogylcerin is given. What is the MOA of this drug.

Back 12

Nitroglycerin (NO release) causes increase cGMP and smooth mucle relaxation -- VENODILATOR --> Decreases preload.

Front 13

Frank-Starling Mechanism

Back 13

Force of contraction if proportional to initial length of the cardiac muscle fiber (preload)

Front 14

____ is an index of ventricular contractility.

Back 14

Ejection fraction.
EF= SV/EDV

Front 15

RESISTANCE, PRESSURE, FLOW:
Flow (Q) is INDEPENDANT when vessels are __________; affecting flow in one vessel does not effect other vessels

Back 15

Total resistance of vessels in PARALLEL;

therefore Q is dependent when the total resistance is in series.

Front 16

Which phase of the cardiac cycle has the most Oxygen consumption?
a) Isovolumetric Contraction phase
b) Systolic Ejection phase
c) Isovolumetric relaxation phase
d) Rapid filling phase
e) Reduced filling phase

Back 16

Isovolumetic contraction phase

Front 17

What phase of the cardiac cycle marks the period just after the mitral valve opens?
a) Isovolumetric Contraction phase
b) Systolic Ejection phase
c) Isovolumetric relaxation phase
d) Rapid filling phase
e) Reduced filling phase

Back 17

Rapid filling period

Front 18

What phase of the cardiac cycle marks the period between the mitral valve closure and aortic valve opening?
a) Isovolumetric Contraction phase
b) Systolic Ejection phase
c) Isovolumetric relaxation phase
d) Rapid filling phase
e) Reduced filling phase

Back 18

Isovolumetric contraction phase

Front 19

What heart sound? Mitral and tricuspid closure.

Back 19

S1

Front 20

Heart sound associated with an increased filling pressure and more commonly in dilated ventricles. Found in early diastole.

Back 20

S3

Front 21

how does INCREASED Contractility effect the following:
1) SV
2) EF
3) ESV

Back 21

1) ↑ stoke volume
2) ↑ ejection fraction
3) ↓ end systolic volume

Front 22

How does INCREASED afterload affect the following
1) Aortic Pressure
2) SV
3) ESV

Back 22

1) ↑ Aortic pressure
2) ↓ Stroke volume
3) ↑ End systolic volume

Front 23

S4 heart sounds are heard when and what causes them?

Back 23

S4 is heard in late diastole. S4 is associated with ventricular hypertrophy.

Front 24

In JVP, the "a" wave represents what?

Back 24

atrial contraction

Front 25

In normal healthy individual, what phase of respiration causes splitting of S2 and why?

Back 25

INSPIRATION → leads to drop in intrathoracic pressure increasing the capacity of pulmonary circulation → pulmonic valve closes later

Front 26

Delayed RV empyting seen in conditions such as pulmonic stenosis and right bundle branch block.

Back 26

Wide Splitting of S2

Front 27

Fixed Splitting of S2

Back 27

ASD

Front 28

Pulmonic valve closes before Aortic valve in ____________. What phase of respiration eliminates the S2 Split?

Back 28

Paradoxical Splitting.

Inspiration

Front 29

Pandiatolic murmur, heard best at the Left Sternal Border?

Back 29

Aortic/Pulmonic Regurgitation

Front 30

Description of heart murmurs that are associated with "Regurgitation"?

Back 30

They will be either Holosystolic or Holodiastolic, high-pitched "blowing" murmur.

Front 31

What are the most common causes of Aortic Stenosis?

Back 31

Aortic Stenosis, due to age-related calcified valves or bicuspid aortic valve.

Front 32

Holosystolic "Harsh" sounding murmur heard best at the Tricupsid Area

Back 32

VSD

Front 33

Describe Aortic Stenosis

Back 33

Late Systolic, Crescendo-Decresendo Murmur preceded by an Ejection Click

Front 34

Late-systolic crescendo murmur with a Mid-Systolic Click

Back 34

Mitral Valve Prolapse

Front 35

continuous machinery murmur

Back 35

PDA

Front 36

What causes the "Plateau" of Phase 2 of the cardiac muscle action potential?

Back 36

Ca++ Influx

Front 37

What causes cardiac nodal cells' spontaneous depolarization resulting in automaticity

Back 37

I"f" Channels, Slow Na+ Influx

Front 38

Cardiac myocytes are electronically coupled to eachother by?

Back 38

Gap Junctions

Front 39

How are Skeletal Muscle and Ventricular Muscle Action Potentials SIMILAR? (2)

Back 39

1) Na+ Voltage-gated Channels are closed at rest
2) K+ Ungated Channels are always open

Front 40

How are Skeletal Muscle and Ventricular Muscle Action Potentials DIFFERENT? (2)

Back 40

1) Ca+ Channels play a role cardiac myocyte action potentials
2) In the heart, voltage-gated K+ channels are CLOSED at Rest; In skeletal muscle, voltage-gated K+ channels are OPEN at Rest.

Front 41

P wave on ECG

Back 41

Atrial depolarization

Front 42

What are some causes of U wave on ECG?

Back 42

hypoKalemia and Bradycardia

Front 43

QT Interval
Shorten < 0.35 - 0.44 sec < Prolonged
What are examples of conditions assocaiated with SHORTENED QT Interval

Back 43

HyperCalcemia
Digitalis

Front 44

QT Interval
Shorten < 0.35 - 0.44 sec < Prolonged
What are examples of conditions assocaiated with Prolonged QT Interval

Back 44

HypoCalcemia
Quinidine
Procanamide
Disopyramide

Front 45

Slow rising onset of the QRS complex on ECG. "Delta wave"

Back 45

Wolff-Parkinson-White Syndrome

Front 46

Pacemaker potentials have only what phases?

Back 46

0, 3, 4

Front 47

PR interval is prolonegd

Back 47

1st degree AV Block

Front 48

1st degree heart block, pr interval is ( > ____ msec)

Back 48

> 200 msec

Front 49

"sawtooth" appearance on ECG, due to rapid succession of identical, back-to-back atrial depolarization waves

Back 49

Atrial Flutter

Front 50

"dropped beat" with progressive lengthening of PR interval

Back 50

2nd Degree AV Block, Mobitz type 1

Front 51

How can you distinguish Mobitz type I from Mobitz type II heart block?

Back 51

Both are 2nd Degree AV block both type I and II have "dropped beats" but Mobitz type II is not associated with gradual lengthening of PR prior to a dropped beat.

Front 52

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

Back 52

Ventricular fibrillation

Front 53

Atria and ventricles are beating independently of each other. Both P waves and QRS complexes are present.

Back 53

3rd Degree (Complete) AV Block

Front 54

What Chemoreceptors monitor changes in arterial pH and PCO2?

Back 54

Central Chemoreceptors

Front 55

Peripheral chemoreceptors (2) respond to what changes in the blood (3).

Back 55

carotid and aortic bodies respond to ↓ PO2, ↑ PCO2, and ↓ pH

Front 56

Starling forces: Edema in Nephrotic syndrome, Liver failure

Back 56

↓ plasma protein; ↓ plasma colloid osmotic pressure - pulls fluid into capillary

Front 57

Starling forces: Edema in Heart Failure

Back 57

↑ capillary pressure; ↑ capillary pressure - pushes fluid out of the capillary

Front 58

Starling forces: Edema in lymphatic blockage

Back 58

↑ interstitial fluid colloid osmotic pressure - pulls fluid out of capillary

Front 59

Starling forces: Edema seen in burn patients

Back 59

↑ capillary permeability = ↑ Kf (filtration constant)

Front 60

Right-to-Left Shunts "blue babies"

Back 60

1. TOF
2. TOGV
3. TA
4. Tricuspid Atrisia
5. TAPVR

Front 61

Left-to-Right Shunts, "blue kids"

Back 61

1. VSD
2. ASD
3, PDA

Front 62

reversal of a L→R shunt to R→L shunt; presents with late cyanosis (clubbing and polycythemia)

Back 62

Eisenmenger's Syndrome

Front 63

Describe TOF

Back 63

1. Pulmonary Stenosis
2.RVH
3.Overriding of the Aorita
4. VSD

Front 64

What is the cause of truncus arteriousis?

Back 64

failure in the formation of the aorticopulmonary septum to divide the truncus arteriosum into the aorta and pulmonary trunks.

Front 65

Child Chest X-ray reveals boot-shaped heart (RVH) with history of cyanotic spells.

Back 65

TOF

Front 66

Hypertension in upper extremities, and weak pulses in the lower extremities

Back 66

Coarctation of the Aorta

Front 67

ASD, VSD, AV septal defects (endocardial cushion defect) are associated with what congenital disorder?

Back 67

Trisomy 21 (Down Syndrome)

Front 68

Septal defects, PDA, and pulmonary artery stenosis are associated with what congenital disorder?

Back 68

enveloped, linear ss-RNA virus (Toga Virus)

Front 69

Aortic insufficiency is associated with what congenital disorder?

Back 69

defect in fibrillin (Marfans)

Front 70

Ischemic Heart disease associated with coronary artery spasm

Back 70

Printzmetal Variant Angina

Front 71

What closes PDA?

Back 71

Indomethacin

Front 72

What will keep the PDA patent?

Back 72

PGE and low O2 tension

Front 73

MC cardiac arrhythmia

Back 73

atrial fibriliation

Front 74

MC primary tumor of the heart

Back 74

Atrial myxoma (usually Left)

Front 75

MC of MI in YOUNG women with SLE

Back 75

Premature coronary atherosclerosis

Front 76

MC cause of acute infective endocarditis

Back 76

gram-positive, grape-like clusters, catalase positive, coagulase positive, β-hemolysis (Staph Aureus)

Front 77

MC cause of subacute infective endocarditis

Back 77

gram-positive streptococci, α-hemolysis (green hemolysis), catalase negative, optichin resistent (Strep Viridans)

Front 78

Infective endocarditis associated with large vegetations on previously normal valves, what microbe?

Back 78

Staph Aureus

Front 79

Infective endocarditis associated with small vegetation on previously diseased/congenitally abnormal valves, what microbe?

Back 79

Strep Viridans

Front 80

MNEUMONIC "FROM JANE" is for what disease?

Back 80

Bacterial Endocarditis:
Fever
Roth's spots
Osler's nodes
Murmur (Mitral valve MC affected)
Janeway lesions
Anemia
Nail-bed hemorrhage
Emboli

Front 81

Causative agent of Rheumatic Heart Disease

Back 81

Group A β-hemolytic Strep (strep pyogenes)

Front 82

What are the manifestation of Rheumatic Heart Dease?

Back 82

Mneumonic: FEVERS
1. Fever
2. Erythema marginatum
3. Valvular damage (mitral>aortic>>tricuspid valve)
4. ↑ ESR
5. Red-hot joints (Migratory polyarthritis)
6. St. Vitus's Dance (Chorea) / Van Sydenham's Chorea

Front 83

What is the pathophysiology of RHD?

Back 83

Type III Hypersensitivity Reaction, Antibodies to M Protein