Updated: 12/17/2020

Coronary Artery Anatomy

0%
Topic
Review Topic
0
0
N/A
N/A
Questions
10
0
0
100%
0%
Evidence
11
0
0
100%
0%
Videos / Pods
2
Topic
https://upload.medbullets.com/topic/108002/images/caa.jpg
Snapshot
  • A 70-year-old man presents to the emergency room with chest pain for the past hour. He has a medical history of coronary artery disease, hyperlipidemia, and type 2 diabetes mellitus. He has a 30-pack-year smoking history and drinks alcohol regularly. His electrocardiogram reveals ST-segment elevations in leads V3 and V4. Aspirin is given and he is rushed for an angioplasty. (Myocardial infarction with left main coronary artery involvement)
Anatomy
  • Coronary arteries include
    • right coronary artery (RCA)
      • arises from right aortic sinus
      • supplies right ventricle and His bundle
      • branches
        • sinoatrial nodal artery
          • supplies the sino-atrial (SA) node
        • right marginal artery
          • supplies the right ventricle
      • posterior descending artery (PDA) supplies
        • AV node (supplied by atrioventricular nodal artery)
        • posterior portion of interventricular septum and ventricles
        • posteromedial papillary muscle
    • left main coronary artery (LCA)
      • arises from left aortic sinus
      • branches
        • left circumflex coronary artery (LCX) supplies 
          • lateral and posterior wall of left ventricle
          • anterolateral papillary muscle
          • supplies some blood flow to SA node and AV node
        • left anterior descending artery (LAD) supplies  
          • anterior portion of the interventricular septum
          • anterolateral papillary muscle
          • anterior surface of the left ventricle
          • most common artery to be involved in myocardial infarction
  • Coronary arterial system dominance
    • defined by which artery supplies the PDA
    • right dominance
      • 85% of cases
      • RCA gives rise to PDA
    • left dominance
      • 8% of cases
      • LCX gives rise to PDA
    • codominance
      • 7% of cases
      • both LCX and RCA give rise to PDA
  • Coronary sinus
    • the endpoint of coronary flow and is continuous with the right atrium
    • in chronic pulmonary hypertension, coronary sinus becomes dilated
    • blood in the coronary sinus has the lowest oxygen content in the body
      • oxygen saturation levels 30%
  • Left atrium
    • most posterior part of the heart
    • enlargement can compress
      • the esophagus, causing dysphagia
      • the left recurrent laryngeal nerve, causing hoarseness
 
Localization of Myocardial Infarctions (MI)
Leads with ST-Segment Elevation
Location of MI
Vessel(s) Affected
V1-V2
  • Septal
  • LAD
V3-V4
  • Anterior
  • LAD
V5-V6
  • Apical
  • LAD, LCX, or RCA
I and aVL
  • Lateral
  • LCX
V7-V9
  • Posterior
  • RCA and LCX
II, III, and aVF
  • Inferior
  • RCA and LCX
 
Pathology
  • Coronary steal phenomenon
    • myocardial ischemia
      • narrowed coronary arteries are dilated maximally to increase blood flow to ischemic tissues
        • when a vasodilator is used, coronary arteries that are not narrowed vasodilate
          • narrowed coronary arteries cannot further dilate
          • thus, blood flow is stolen from the narrowed arteries
        • classically, dipyridamole is associated with this
          • also used for cardiac stress testing

Please rate topic.

Average 4.6 of 20 Ratings

Questions (10)
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(M1.CV.17.4723) A 55-year-old man with a past medical history of hypertension, hyperlipidemia, and insulin dependent diabetes mellitus presents to the ED with a sudden onset of substernal chest pain and pressure that radiated into his neck and down his left arm. The pain started a few hours ago while he was watching television. It was not relieved by rest. He was given aspirin by EMS en route to the hospital. His current medications are glargine insulin, hydrochlorothiazide, and atorvastatin. He has not had any similar episodes previously. His family history is significant for an uncle who had a heart attack at age 45. He drinks one drink every other day and has a 25-pack-year smoking history. His temperature is 99.0°F (37.2°C), blood pressure is 150/90 mmHg, pulse is 63/minute, respirations are 22/minute, and point-of-care glucose level is 110 mg/dl. Troponin level is elevated. EKG is shown in Figure A. What is the most likely etiology of this patient’s presentation?

QID: 108549
FIGURES:
1

Left main coronary artery occlusion

12%

(28/243)

2

Right main coronary artery occlusion

30%

(73/243)

3

Left circumflex artery occlusion

15%

(37/243)

4

Left anterior descending artery occlusion

38%

(93/243)

5

Coronary vasospasm

1%

(3/243)

M 2 C

Select Answer to see Preferred Response

Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(M1.CV.13.150) A 24-year-old man presents to the emergency room with a stab wound to the left chest at the sternocostal junction at the 4th intercostal space. The patient is hemodynamically unstable, and the trauma attending is concerned that there is penetrating trauma to the heart as. Which cardiovascular structure is most likely to be injured first in this stab wound?

QID: 100666
1

Left atrium

6%

(5/81)

2

Left ventricle

23%

(19/81)

3

Right atrium

4%

(3/81)

4

Right ventricle

62%

(50/81)

5

Aorta

4%

(3/81)

M 1 E

Select Answer to see Preferred Response

(M1.CV.13.204) In the coronary steal phenomenon, vessel dilation is paradoxically harmful because blood is diverted from ischemic areas of the myocardium. Which of the following is responsible for the coronary steal phenomenon?

QID: 100720
1

Venodilation

3%

(2/74)

2

Microvessel dilation

46%

(34/74)

3

Dilation of the large coronary arteries

30%

(22/74)

4

Arterial dilation

18%

(13/74)

5

Volume loss of fluid in the periphery

1%

(1/74)

M 1 E

Select Answer to see Preferred Response

(M1.CV.13.48) A healthy 23-year-old male is undergoing an exercise stress test as part of his physiology class. If blood were to be sampled at different locations before and after the stress test, which area of the body would contain the lowest oxygen content at both time points?

QID: 100564
1

Superior vena cava

4%

(19/488)

2

Inferior vena cava

12%

(60/488)

3

Coronary sinus

32%

(156/488)

4

Pulmonary artery

42%

(203/488)

5

Pulmonary vein

7%

(34/488)

M 1 C

Select Answer to see Preferred Response

(M1.CV.13.1) A 62-year-old Caucasian male presents to the emergency room with severe substernal chest pain, diaphoresis, and nausea. Imaging reveals transmural myocardial infarction in the posterior 1/3 of the ventricular septum. Which of this patient's coronary arteries is most likely occluded?

QID: 100803
1

Left circumflex

17%

(16/96)

2

Left anterior descending

5%

(5/96)

3

Diagonal perforators

2%

(2/96)

4

Septal perforators

4%

(4/96)

5

Right main

72%

(69/96)

M 1 E

Select Answer to see Preferred Response

(M1.CV.12.24) A 49-year-old male presents to the emergency room with dyspnea and pulmonary edema. He reports that he has been smoking 2 packs a day for the past 25 years and has difficulty breathing during any sustained physical activity. His blood pressure is normal, and he reports a history of COPD. An echocardiogram was ordered as part of a cardiac workup. Which of the following would be the most likely finding?

QID: 100540
1

Aortic stenosis

11%

(9/79)

2

Mitral valve insufficiency

25%

(20/79)

3

Left ventricular hypertrophy

38%

(30/79)

4

Coronary sinus dilation

15%

(12/79)

5

Tricuspid valve stenosis

6%

(5/79)

M 1 E

Select Answer to see Preferred Response

Evidence (11)
VIDEOS & PODCASTS (2)
EXPERT COMMENTS (16)
Private Note