Anatomy
This was previously featured in an exam
Thorax
A 61 year old patient presents to ED with sudden onset central crushing chest pain. ECG demonstrates a STEMI and bradycardia with a heart rate of 45 bpm. Which of the following vessels is most likely occluded:
Answer:
The right coronary artery in the majority of cases supplies the SA and the AV node. Occlusion of the right coronary artery can result in ischaemia of one or both of the nodes, with subsequent bradycardia and/or heart block.Cardiac Blood Supply
Anatomy / Thorax / Heart and Pericardium
Last Updated: 26th May 2023
The right and left coronary arteries arise from the right and left aortic sinuses in the initial portion of the ascending aorta and supply the muscle and other tissues of the heart.
Territories of Supply
Although there is variation, in most people the territories of supply are as follows:
The right coronary artery supplies:
- the right atrium
- most of the right ventricle
- the sinoatrial and atrioventricular nodes
- the interatrial septum
- a portion of the left atrium
- the posteroinferior one-third of the interventricular septum
- a portion of the posterior part of the left ventricle
The left coronary artery supplies:
- most of the left atrium
- most of the left ventricle
- a portion of the right ventricle
- most of the interventricular septum (including the atrioventricular bundle and branches)
Branches
Table: Blood Supply of the Heart
| Artery | Territory of Supply |
|---|---|
| Right coronary artery | Right atrium and ventricle, sinoatrial node, atrioventricular node |
| Right marginal branch | Inferior aspect of right ventricle |
| Posterior interventricular branch | Posterior aspect of right and left ventricles, posterior one-third of interventricular septum |
| Left coronary artery | Via main branches below |
| Anterior interventricular branch | Right and left ventricles, anterior two-thirds of interventricular septum |
| Left circumflex branch | Left atrium and left ventricle |
The right coronary artery supplies the right atrium, the sinoatrial node and the atrioventricular node (via the SA and AV nodal branches) and gives rise to two principal branches:
- the right marginal branch (supplying the inferior margin of the right ventricle and the apex)
- the posterior interventricular branch (supplying the posterior aspect of the right and left ventricles and the posterior one-third of the interventricular septum).
The left coronary artery gives rise to two principal branches:
- the anterior interventricular branch (supplying the right and left ventricles, the apex and the anterior two-thirds of the interventricular septum)
- the circumflex branch (supplying the left atrium and left ventricle).
Cardiac Blood Supply. (Image by OpenStax College [CC BY 3.0 , via Wikimedia Commons)
Report A Problem
Is there something wrong with this question? Let us know and we’ll fix it as soon as possible.
Loading Form...
- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
