Heart

Question 1

List MI DDx.

Answer 1

CVS
o	Angina (stable)
o	Arrhythmia 
o	Pericardial effusion/pericarditis 
o	Aortic aneurysm/dissection 
Respiratory
o	PE (pleuritic, sharp)
o	Pneumothorax
o	Pulmonary oedema (HF)
o	Pneumonia/pleuritis 
GIT
o	GORD
o	Oesophagitis 
o	Oesophageal perforation (transmural- Boerrhave syndrome, non-transmural- Mallory Weiss tear)
o	Acute pancreatitis 
Psychiatric
o	Anxiety disorder- panic attack 
MSK injury
o	Chest trauma- rib #
o	Intercostal muscle injury

Question 2

Describe the course of the RCA.

Answer 2

Pathway
⇒Arises in R aortic sinus (ascending aorta) -> atrioventricular groove
⇒ Passes below pulmonary trunk (between R auricle and infundibulum of R heart)
⇒ Descends in atrioventricular groove
⇒ Continues posto-inferiorly into base of heart

Question 3

What are the branches of the RCA?

Answer 3

Branches:
o SA nodal artery -> supplies SA node (60% hearts)
o R marginal artery -> supplies apex and part of RV
o AV nodal artery -> supplies AV node (emerges in characteristic posterior upward “kink”)
o Posterior descending artery (PDA)-> IV septum (posterior 1/3)
• PDA arises from RCA (right dominant), or end of LAD (left dominant, 10% cases)

Question 4

What does the RCA supply?

Answer 4

o	RA
o	RV
o	LV (posterior aspect) 
o	SA node and AV node
o	Inter-atrial septum
o	Part of IV septum (posterior 1/3)

Question 5

Describe the course of the LCA.

Answer 5

Pathway:
⇒ LCA arises in the L aortic sinus (between left auricle and infundibulum of RV)
⇒ Bifurcates to left circumflex (LCX) and left anterior descending (LAD)

Question 6

What are the branches of the LCA?

Answer 6

Branches:
LCX
• Courses around base of heart via atrioventricular groove -> anastomoses with RCA
• Branches:
- Left marginal artery
- Sometimes SA nodal artery (40% hearts)
• Supplies: LV (posterior and lateral walls), anterolateral papillary muscle

LAD
• Courses in anterior interventricular groove towards apex
• Branches:
- Several large ventricular branches to the left
- Conus branches- upper part of RV
• Anastomoses with PDA from RCA at apex
• Supplies: most of LA, LV, interventricular septum (including AV-bundle)

Question 7

What is the coronary sinus?

Answer 7

• Collection of veins joined to form large vessel, collecting blood from myocardium
• Then delivers less-oxygenated blood to RA (as do SVC and IVC)
• Drains into RA via coronary sinus orifice (between IVC and tricuspid valve)

Question 8

What are the coronary sinus tributaries?

Answer 8

1. Great cardiac vein: apex -> ascends anterior interventricular groove (beside LAD) -> upper (left) end of coronary sinus
2. Middle cardiac vein: apex -> ascents in posterior interventricular groove (beside PDA) -> coronary sinus
3. Small cardiac vein: accompanies marginal branch of the RCA -> drains into coronary sinus (or directly into RA)
4. Posterior vein of LV: joins coronary sinus to left of middle cardiac vein
5. Oblique vein of LA: runs downwards into left end of coronary sinus

Question 9

What are the likely locations of thrombi formation?

Answer 9

• LAD- first 1.5-2cm
• LCX- first 1.5-2cm
• RCA- proximal 1/3 and distal 1/3

Question 10

What are the common sites of stenosis and atherosclerosis in the coronary sinus?

Answer 10

• LAS occlusion (40-50%)- proximal 2cm
- Supplies: interventricular septum (2/3rds), LV, majority LA -> anterior heart surface
• LCA occlusion (15-20%)- proximal 2cm
- Supplies: LA, LV (postero-lateral aspect) -> lateral and posterior heart surfaces
• RCA occlusion (30-40%)- proximal 1/3 or distal 1/3
- Supplies: interventricular septum (1/3rd), RA, RV, LV (inferior aspect) -> inferior and posterior heart surfaces
• PDA occlusion
- Supplies: posterior surface of heart

Question 11

What is the arterial supply for the SA and AV node?

Answer 11

• SA node: SA nodal artery supplied by the RCA early branches (60% hearts) and LCX early branches (40%)
• AV node: supplied by AV nodal artery from RCA

Question 12

What are the locations of potential heart rupture post MI?

Answer 12

1. LV wall rupture 
(heart soft due to granulation tissue)
-> cardiac tamponade -> death (90%)
2. Rupture of intraventricular septum
-> VSD -> L to R shunt -> RV overload -> increased pulmonary blood flow -> secondary overload of LA and LV -> declined forward flow -> compensatory vasoconstriction -> increased TPR -> increased L to R shunt -> haemodynamic compromise
3. Papillary muscle 
(assoc w inferior MI)
-> mitral regurgitation -> LVF -> acute pulmonary oedema

Question 13

Give examples of systolic and diastolic murmurs?

What are some combined murmurs?

Answer 13

Systolic murmurs:

• Aortic stenosis
• Pulmonary stenosis
• Mitral regurgitation
• Tricuspid regurgitation
• ASD
• VSD
• Flow murmur

Diastolic murmurs:

• Aortic regurgitation
• Pulmonary regurgitation
• Mitral stenosis
• Tricuspid stenosis

Combined murmurs:

• PDA
• Severe aortic coarctation
• Acute severe aortic regurgitation

Question 14

List some acute complications post MI.

Answer 14

o Arrhythmia (VF/VT, sinus bradycardia, AV block) (75-95%)
o Mural thrombo-embolism
o Cardiogenic shock
o Re-infarction or extension of current infarct
o Dysfunctional contraction (10%)
o Rupture- papillary muscle, LV wall (8%)

Question 15

List some subacute complications post MI.

Answer 15

o Post-infarct fibrinous pericarditis
o Dressler’s syndrome (autoimmune fibrinous pericarditis)
o Rupture- interventricular septal, LV wall
o Emboli form mural thrombus (15-40%)

Question 16

List some long-term complications post MI.

Answer 16

o Rupture (5%)- LV wall (tamponade), VSD, papillary muscle (valvular incompetence)
o Heart failure, LVF (60%)
o Stroke risk ongoing (from thrombo-emboli)