Anatomy
Thorax
A 54 year old man presents to ED with central crushing chest pain. Later coronary angiograms show thrombosis in the circumflex branch of the left coronary artery. Which of the following conditions is most likely to result from obstruction to flow:
Answer:
The circumflex branch of the left coronary artery supplies the left ventricle and thus its blockage results in necrosis of the myocardium in the left ventricle, producing mitral valve insufficiency. The tricuspid valve is in the right ventricle. The SA and AV node are usually supplied by the right coronary artery. The interventricular septum is supplied anteriorly by the anterior interventricular artery and posteriorly by the posterior interventricular artery.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)
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- 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 |
