Heart

Question 0

Depends through the mediastinum lateral to fibrous pericardium

Answer 0

Phrenic nerve

Pericardiophrenic artery

Question 1

3 layers of the Pericardium

Answer 1

1. Visceral layer of serous pericardium
2. Parietal layer of serous pericardium
3. Fibrous pericardium - fuses with the ff:
   - adventitia of great vessels superiorly
   - central tendon of diaphragm inferiorly
   - sternum anteriorly

Question 2

Recess between the great arteries & pulmonary veins

Answer 2

Transverse sinus

Question 3

Recess of pericardial cavity

Ends in a cul-de-sac surrounded by pulmonary veins

Answer 3

Oblique sinus

Question 4

Fluid compresses the heart because the fibrous pericardium is inelastic

Paradoxical pulse (inspiratory lowering of systolic BP by >10mmHg)

SVC compression –> facial & neck veins engorgement

Answer 4

Cardiac tamponade

Question 5

Beck’s triad

Answer 5

Hypotension (that doesn’t respond to rehydration)

High venous pressure

Distant heart sounds

Question 6

Pericardiocentesis

STERNAL APPROACH

Answer 6

ICS 5 or 6 left side near sternum

Penetrates the ff:

• skin
• superficial fascia
• Pectoralis major
• external intercostal muscle
• internal intercostals muscle
• transverse thoracic muscle
• fibrous pericardium

Structures at risk:

• internal thoracic artery
• coronary arteries
• pleura

Question 7

Pericardiocentesis

SUBXIPHOID APPROACH

Answer 7

Left infrasternal angle, angled superiorly & posteriorly

Penetrates the ff:

• skin
• superficial fascia
• anterior rectus sheath
• rectus abdominis
• transverse abdominis muscle
• fibrous pericardium
• parietal layer of serous pericardium

Structures at risk:

• diaphragm
• liver

Question 8

Surfaces of the heart

Answer 8

Posterior surface (base): LA

Apex: LV at ICS5, MCL

Sterna surface: RV

Diaphragmatic surface: LV

Question 9

Borders of the heart

Answer 9

R border: RA, SVC

L border: Aortic arch, pulmonary trunk, LA, LV

Inferior border: RV

Superior border: SVC, aorta, pulmonary trunk

Question 10

Frequency of coronary occlusion in descending order

Answer 10

Anterior interventricular artery (L anterior descending artery)

R coronary artery

Circumflex artery

Question 11

R coronary artery

Answer 11

Branches:

• SA nodal artery
• R marginal artery
• AV nodal artery
• Terminal branches
• Posterior interventricular artery
• Septal branches

Structures supplied:

• RA
• RV
• SA node
• AV node
• Interventricular septum

Question 12

L coronary artery

Answer 12

Circumflex artery

• anterior marginal artery
• obtuse marginal artery
• arterial branches
• post marginal artery

Anterior interventricular artery

• anterior diagonal artery
• septal branches

Structures supplied:

• LA
• LV
• Interventricular septum

Question 13

Venous drainage

Answer 13

GREAT CARDIA VEIN

• follows anterior interventricular artery
• drains into coronary sinus

MIDDLE CARDIAC VEIN

• follows posterior interventricular artery
• drains into coronary sinus

SMALL CARDIAC VEIN

• follows right marginal artery
• drains into coronary sinus

ANTERIOR CARDIAC VEIN

• found on anterior aspect of RV
• drains into directly to RA

SMALLEST CARDIAC VEIN

• begin within the wall of the heart
• directly to the nearest heart chamber

Question 14

Heart valves & Auscultation sites

Answer 14

PULMONARY VALVE (semilunar)

• 3 cusps (R,L, & posterior)
• L ICS 2, parasternal

AORTIC VALVE (semilunar)

• 3 cusps (R,L & posterior)
• R ICS 2, parasternal

MITRAL (left AV valve)

• 2 cusps (anterior & posterior) tethered to papillary muscle by chordate tendinae
• cardiac apex, L ICS 5, MCL

TRICUSPID (right AV valve)

• 3 cusps (anterior, posterior & septal) tethered to papillary muscle by chorda tendinae
• ICS 5, over the sternum

Question 15

Conduction system

Answer 15

SA node

AV node

Bundle of His

Left & right bundle

Purkinje fibers

Question 16

Pacemaker, just beneath the pericardium, at the junction of SVC & RA

Answer 16

SA node

Question 17

Just beneath the endocardium

On the R side of interarterial septum

Near the ostium of coronary sinus

Answer 17

AV node

Question 18

Travels in subendocardial layer

On the R side of Interventricular septum

Answer 18

Bundle of His

Question 19

Left bundle further divides into thin anterior & thick posterior division

Answer 19

Left & right bundle

Question 20

As terminal branches

Answer 20

Purkinje fibers

Question 21

Abnormal migration of neural crest cells –> skewed aorticopulmosegment –> R to L shunt –> cyanosis

4 components:

• pulmonary stenosis
• RVH
• overriding aorta
• VSD

Answer 21

Tetralogy of Fallot (TOF)

Question 22

Incomplete fusion of R and L bulbar ridge and AV cushions –> L to R shunt initially –> if uncorrected, ⬆️ pulmonary blood flow –> pulmonary hypertension –> R to L shunt (Eisenmenger complex)

Answer 22

Membranous VSD

Question 23

Ductus arteriosus (DA)

Fails to close (connection between L pulmonary artery & aortic arch) –> L to R shunt

DA normally closes within few hours after birth to form the Ligamentum arteriosum

Premature infants
Maternal rubella during pregnancy

Maintains patency: PG E1, asphyxia

Promotes closure:

• PG inhibitors (indomethacin)
• ACH
• histamine
• catecholamines

Answer 23

Patent ductus arteriosus (PDA)

Question 24

MC cause: atherosclerosis Precipitated by exertion, relieved by rest, <30mins

Answer 24

Ischemic heart disease Angina pectoris

Question 25

Mac cause: atherosclerosis Complications: CHF, arrhythmia (1st 24 hours) ECG: ST elevation --> Q waves, inverted T waves Cardiac enzymes: CK (6-12 hours), Troponin (12 hours), LDH (reversed LDH1:LDH2 ratio 24 horus after) Treatment & rationale: - sublingual nitroglycerin (vasodilator) - b-blocker (relieve tachycardia, hypertension) - tPA/streptokinase (reduce infrared tissue) - atropine (relieve bradycardia) - warfarin/heparin (prevent ventricular aneurysm, embolism, DVT)

Answer 25

Acute myocardial infarction

Question 26

RV dilatation caused by pulmonary hypertension Acute - following a large thrombopulmonary embolism Chronic - due to prolonged obstruction of pulmonary vasculature (e.g. Emphysema)

Answer 26

Cor pulmonale

Question 27

Fibrous scarring & calcium nodules MC affects aortic valve

Answer 27

Calcific valve disease

Question 28

Anti-streptococcal antibodies cross-react with heart valves MC affects mitral valve --> smart, wart-like vegetations (verrucae), " fish mouth or button hole", stenosis Pathognomonic lesion: Aschoff bodies (perivascular, fibrinoid, necrosis-surrounded inflammatory Aschoff cells)

Answer 28

Rheumatic heart disease

Question 29

ACUTE - S. Aureus (50%), Strep 35%) - previously normal valves - Large friable vegetations --> septic emboli SSX: - splinter hemorrhages in nail beds - Janeway lesions (nontender, palms & soles)

Answer 29

Acute infective endocarditis

Question 30

S. Epidermis, S. Viridans, Enterococcus sp. Gram negative bacilli Previously abnormal valves SSX: - Rott spots (retinal hemorrhages) - Osler nodes (tender, fingers & toes) - anemia, hematuria, splenomegaly

Answer 30

Infective endocarditis (SUBACUTE)

Question 31

Congenital, accessory conduction pathway Re-entry loop may develop --> supraventricular tachycardia

Answer 31

Wolff-Parkinson-White syndrome