Cardiology

Question 1

What causes S3 heart sound?

Answer 1

• Rapid filling of ventricle during diastole
• Normal in young individuals and pregnant patients
• In patients > 40 years, it is due to left ventricular volume overload/failure
• Examples: aortic or mitral regurgitation, dilated cardiomyopathy

Question 2

What causes S4 heart sound?

Answer 2

• Rapid filling of ventricle during systole (atrial contraction)
• Stiff ventricle
• Normal in healthy older adults
• Abnormal in younger adults and children
• Heard in diastolic dysfunction (e.g. LVH)

Question 3

What is the mechanism of action of Digoxin?

Answer 3

• Digoxin is a cardiac glycoside that inhibits the cardiac Na+-K+ ATPase.
• It indirectly inhibits the Na+Ca2+ exchanger used to clear Ca2+ from the sarcoplasm following excitation, which leads to increased intracellular Ca2+ and positive inotropy.
• It also inhibits the neuronal Na+-K+ ATPase, resulting in increased vagal nerve activity and a decrease in heart rate
• It increases inotropy, decreases AV conduction, and depressed the SA node.

Question 4

What is the triad for Wegener granulomatosis (granulomatosis with polyangiitis)?

Answer 4

Wegener granulomatosis is an autoimmune disease that causes necrotizing vasculitis with granuloma formation.

Triad for Wegener granulomatosis:

1. Upper respiratory tract (rhinitis, sinusitis)
2. Lower respiratory tract (hemoptysis, pulmonary lesions)
3. Kidney involvement (necrotizing glomerulonephritis)

Question 5

Which disease is associated with endomyocardial fibrosis and hypereosinophilia?

Answer 5

• Loeffler endocarditis aka endomyocardial fibrosis with hypereosinophilia syndrome is associated with endomyocardial fibrosis with myocyte necrosis and a prominent eosinophilic infiltrate
• This condition appears to be the result of direct toxicity to the heart by proteins (eosinophil ribonuclease and eosinophil major basic protein) in eosinophil granules designed to kill large parasites

Question 6

What is Chagas disease?

Answer 6

• Chagas disease is characterized by myocarditis and megacolon
• Results from infections by Trypanasoma cruzi (endemic in Central and South America)
• Hyperesosinophilia is present

Question 7

What happens when MAP is decreased?

Answer 7

• Baroceptor reflex: increases sympathetic activity and decreases parasympathetic (vagal) activity
• Baroreceptor reflex:
  
  • increases HR
  • increases inotropy
  • venoconstriction to increase CO
  • constricts small arteries and arterioles to increase SVR
• Decreased MAP stimulates epinephrine release
• Decreased renal perfusion pressure activates RAAS

Question 8

What is the main heart valvular disease seen in rheumatic heart disease?

Answer 8

Mitral regurgitation is the most common heart valvular disease in rheumatic heart disease. Mitral stenosis usually develops after the initial episode.

Question 9

What is Becks’ Triad?

Answer 9

Becks triad is seen in cardiac tamponade:

1. hypotension
2. muffled heart sounds
3. increased JVP

Question 10

What is pulsus paradoxus?

Answer 10

• Pulsus paradoxus is associated with cardiac tamponade.
• Normally there is a slight drop in BP during inspiration. In cardiac tamponade, the effect is exaggerated (>10 mmHg drop in pressure)

Question 11

What is the most serious complication of Digoxin toxicity?

Answer 11

Cardiac arrhythmias

Question 12

What are the roles of angiotensin II?

Answer 12

1. Increases sympathetic activity
2. Increases aldosterone secretion from the adrenal cortex
3. Increases sodium and chloride reabsorption and potassium excretion
4. Increased ADH secretion from the pituitary
5. Causes arteriolar constriction

Question 13

What are the two histopathologic patterns of malignant nephrosclerosis (caused by severe hypertension)?

Answer 13

Severe hypertension can cause damage to the vascular endothelium, leading to increased vascular permeability to coagulation factors (e.g. fibrinogen), platelet activation, and endothelial cell death.

Malignant nephrosclerosis is characterized by:

1. Fibrinoid necrosis: cell death and excessive fibrin deposition within the arteriolar walls is visible as circumferential amorphous, pink material with smudged, necrotic endothelial cells that lack cytologic detail
2. Hyperplastic arteriolosclerosis: over time, activated platelets and injured cells release growth factors, which induce concentric hyperplasia and layering of smooth muscle cells and collagen resulting in intimal thickening and an “onion-skin” appearance

Question 14

What is the best indicator of mitral stenosis severity on auscultation?

Answer 14

The best indicator of mitral stenosis severity on auscultation is the length of time between s2 (A2) and the opening snap.

Question 15

Which organism is associated with colon cancer when found in blood culture?

Answer 15

Streptococcus gallolyticus (formerly S. bovis)

Question 16

When does heart failure with preserved ejection fraction develop?

Answer 16

Heart failure with preserved ejection fraction develops due to diastolic dysfunction, which frequently occurs in the setting of prolonged systemic hypertension.

Question 17

Which class III antiarrhythmic drug also has beta blocking activity?

Answer 17

Sotalol has both potassium channel blocking and beta blocking activity

Question 18

What are the watershed areas?

Answer 18

The watershed areas are:

1. Rectosigmoid junction
2. Splenic flexure
3. Brain: junction of anterior, middle and posterior cerebral arteries