Cardiovascular

Question 1

What is the mediator of the side effects associated with niacin use?

Answer 1

Prostaglandins cause flushing, warmth and itching. These symptoms can be significantly reduced by taking aspirin 30-60 minutes before taking niacin.

Question 2

What effects does niacin have on lipid levels?

Answer 2

Raises HDL and lowers TGs

Question 3

What is a side effects of selective arteriolar vasodilators (e.g. hydralazine, minoxidil)?

Answer 3

They cause selective vasodilation of arterioles but does not veins. This causes stimulation of baroreceptors resulting in reflex sympathetic activation. This causes tachycardia, increased contractility and cardiac output. The sympathetic nervous system also stimulates the renin-angiotensin-aldosterone axis, which results in sodium and fluid retention with peripheral edema.

Question 4

What is the “wear and tear” insoluble pigment seen in the myocardial cells of elderly patients?

Answer 4

Lipofuscin: Lipid polymers and protein-complexed phospholipids that are damaged as a result of free radical injury and lipid peroxidation. This produces a yellow-brown, finely granular perinuclear pigment.

Question 5

What is the best way to increase the forward-to-regurgitant flow ratio in a patient with mitral regurgitation?

Answer 5

Decrease afterload with a selective arteriole dilator (e.g. hydralazine)

Question 6

How does nitroglycerine work?

Answer 6

It acts primarily as a venodilator at lower doses. Cardiac workload is decreased because blood collects in the venous system thereby decreasing preload. This decreases ventricular wall stress which decreases cardiac oxygen demand. Large veins are the most susceptible to the effect of nitroglycerine.

Question 7

How does digoxin decrease heart rate?

Answer 7

Increased parasympathetic tone (via vagus nerve).

Question 8

What are the findings when auscultating aortic regurgitation?

Answer 8

Best heard at left sternal border. Characterized by an early diastolic murmur.

Question 9

What happens to blood pressure in the setting of acute cardiac tamponade?

Answer 9

Pulsus paradoxus (an exaggerated drop of >10 mmHg in systolic BP during inspiration). Inspiration causes an increase in venous return, resulting in increased heart volumes. Under normal conditions, this results in expansion of the right ventricle into the pericardial space with little impact on the left side of the heart. In the setting of acute cardiac tamponade, and occasionally constrictive pericarditis, their is impaired expansion and the interventricular septum bows into the left ventricle during inspiration causing a decrease in stroke volume and thus systolic BP.
Asthma and COPD exacerbation are the most frequent causes of pulsus paradoxus in the absence of significant pericardial disease (large drop in intrathoracic pressure during inspiration).

Question 10

Which arteries are most susceptible to atherosclerosis?

Answer 10

The lower abdominal aorta and the coronary arteries.

Question 11

How soon are small ventricular septal defects (VSDs) heard after birth?

Answer 11

Usually they become audible around age 4-10 days and pulmonary vascular resistance (PVR) continues to decline, permitting significant left-to-right shunting. Most small VSDs will close spontaneously and are hemodynamically insignificant.

Question 12

Where are Beta-1 receptors found?

Answer 12

Cardiac tissue and on the renal juxtaglomerular cells. They are not in vascular smooth muscle. Coupled to Gs so they cause an increase in intracellular cAMP.

Question 13

What are maneuvers that can be used to treat paroxysmal supraventricular tachycardia?

Answer 13

Vagal stimulation such as carotid sinus massage and the Valsalva maneuver. Maneuvers that increase vagal tone increase the refractory period of the AV node and help prevent a reentrant circuit from conducting. If the Valsalva measures fail, IV administration of adenosine is recommended.

Question 14

What cardiac defects are associated with a chromosome 22q11.2 deletion?

Answer 14

Tetralogy of Fallot, truncus arteriosus, and interrupted aortic arch.

Question 15

What are the cardiovascular risks associated with obstructive sleep apnea (OSA)?

Answer 15

Prolonged OSA can cause pulmonary hypertension due to hypoxemia leading to pulmonary vasoconstriction (which can lead to right heart failure). Most patients with OSA will develop systemic hypertension due to chronic sympathetic stimulation and elevated plasma NE levels.

Question 16

Mitral valve prolapse (MVP) is due to a defect in what component of the valve?

Answer 16

The connective tissue. Primary MVP is most commonly a sporadic disorder and is characterized by myxomatous degeneration (i.e. pathologic deterioration of the connective tissue) affecting the mitral valve leaflets and chordae tendineae. Secondary MVP is associated with inherited CT disorders, including Marfan syndrome, Ehlers-Danlos syndrome, or osteogenesis imperfecta.

Question 17

What does PDA murmur sound like?

Answer 17

A continuous murmur with inspiratory splitting of S2, best heard at in the left infraclavicular region.

Question 18

What tissue in the body is the most effective at extracting oxygen from arterial blood?

Answer 18

Cardiac tissue. The resting myocardium extracts 60-75%of oxygen from blood. As a result, cardiac venous blood is the most deoxygenated.

Question 19

What effect does viral myocarditis have on the heart?

Answer 19

It can cause dilated cardiomyopathy, leading to heart failure.

Question 20

What extra heart sound is often heard in patients with severe mitral regurgitation?

Answer 20

S3 gallop due to an increased rate of left ventricular filling.

Question 21

What is the mechanism of action of ivabradine?

Answer 21

It slows the rate of SA node firing by selectively inhibiting the funny sodium channels (If), thereby prolonging the slow depolarization phase (phase 4). It is the only drug that slows heart rate (negative chronotropic effect) with no effect on cardiac contractility (inotropy) and/or relaxation (lusitropy). Used in patients with heart failure with reduced ejection fraction. Shown to reduce risk of hospitalization.

Question 22

What are Aschoff bodies?

Answer 22

Interstitial myocardial granulomas that are pathognomonic for acute rheumatic fever-related myocarditis. Within the granuloma, plump macrophages with abundant cytosplasm and central, slender chromatin ribbons called Antischkow cells are often present.

Question 23

What is the best way to hear an S3 heart sound?

Answer 23

Best heard with the bell of the stethoscope over the cardiac apex while the patient is in the left lateral decubitus position at end expiration. Listening at end expiration makes the sound even more audible by decreasing lung volume and bringing the heart closer to the chest wall.

The sound is decreased by the Valsalva maneuver and abrupt standing due to decreased venous return.

Question 24

What does atrial fibrillation show on an EKG

Answer 24

Irregularly irregular rhythm, absent P waves, and varying R-R intervals.

Question 25

What congenital cardiac abnormality is associated with berry aneurysms of the Circle of Willis?

Answer 25

Coarctation of the aorta

Question 26

What are two equations for calculating cardiac output?

Answer 26

CO=SV x HR

CO= rate of O2 consumption / ateriovenous O2 content difference

Question 27

What is the underlying embryologic event that leads to tetrology of Fallot?

Answer 27

Deviation of the infundibular septum

Question 28

What is subclavian steal syndrome?

Answer 28

Significant stenosis of the subclavian artery proximal to the origin of the vertebral artery. This causes retrograde blood flow in the vertebral artery of the affected side, as it is not supplying blood to the subclavian artery past the stenotic lesion (receives blood from the contralateral vertebral artery). Most patients are asymptomatic but some patients may have vertebrobasilar insufficiency (e.g. dizziness, vertigo, drop attacks) or arm ischemia of the affected limb. Can present with decreased BP in the affected arm compared to the contralateral arm.

Question 29

During exercise, what changes are seen in total systemic vascular resistance?

Answer 29

Decreased total peripheral vascular resistance:
Exercising muscles can receive up to 85% of total cardiac output during periods of strenuous activity. Although sympathetic discharge during exercise causes increased cardiac output and splanchnic vasoconstriction, there is only a modest increase in mean blood pressure as vasodilation within active skeletal muscles significantly decreases the total systemic vascular resistance.

Question 30

What mitochondrial changes are seen in irreversible myocardial injury?

Answer 30

The appearance of vacuoles and phospholipid-containing amorphous densities within mitochondria.

Question 31

What artery is occluded in a STEMI with ST elevations in leads II, III, and aVF?

Answer 31

The right coronary artery in right dominant hearts. The patient may also have bradycardia if the SA node is affected.

Question 32

Where is the AV node located?

Answer 32

The endocardial surface of the right atrium, near the insertion of the septal leaflet of the tricuspid valve and the orifice of the coronary sinus.

Question 33

In what order are vessels primarily affected by atherosclerosis?

Answer 33

Abdominal aorta > coronary arteries > popliteal arteries > internal carotids > circle of Willis

Question 34

Why do patients with severe aortic stenosis who develop atrial fibrillation present with sudden decrease in blood pressure?

Answer 34

These patients are reliant upon adequate left atrial contraction to fill the stiff left ventricle (due to hypertrophy from working against a stenotic valve). A-fib occurs in up to 10% of patients with severe aortic stenosis.

Question 35

What cell type forms the fibrous cap (made of collagen) seen in atherosclerotic plaques?

Answer 35

Smooth muscle cells

Question 36

What is Kussmaul sign?

Answer 36

A paradoxical rise in JVP during inspiration (usually falls during inspiration). Occurs in the setting of constrictive pericarditis.

Question 37

How soon after an MI does free wall rupture typically occur?

Answer 37

5-14 days

Question 38

What type of heart failure does transthyretin deposition cause?

Answer 38

Diastolic HF due to reduced LV compliance. If there is a mutation in the transthyretin gene, the protein can misfold and cause amyloid protein that infiltrates the myocardium.

Question 39

What type of cardiomyopathy does alcohol, doxorubucin therapy, selenium deficiency, and viral myocarditis cause?

Answer 39

Dilated cardiomyopathy

Question 40

On fondoscopic exam, what damage to the retina is commonly seem with uncontrolled hypertension?

Answer 40

Retinal (flame) hemorrhage, thickening of the arteriolar walls (“copper or silver wiring”), compression of associated veins (arteriovenous nicking), and small, white foci of retinal ischemia (cotton-wool spots).

Question 41

What is the purpose of paclitaxel in drug eluting coronary stents?

Answer 41

Prevents intimal hyperplasia, thus preventing stent restenosis.