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# Middle cardiac vein

The middle cardiac vein runs in the groove on the underside of the heart, beside the posterior descending artery, and drains into the coronary sinus.

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## What it is

Runs in the posterior interventricular groove, from the apex up to the coronary sinus, side by side with the posterior descending artery.

## What it does

Drains the back (diaphragmatic) wall of both ventricles and the back of the septum.

## Key points

- Joins the [coronary sinus](https://durgical.com/en/anatomy/coronary-sinus/) close to its opening, so it is the first large tributary a catheter meets after entering the sinus
- Posteroseptal (inferior paraseptal) accessory pathways can be mapped and ablated from inside it
- An alternative route for the left ventricular lead in resynchronization when the lateral veins are unsuitable

## Key facts

**Drains**
Inferior (diaphragmatic) walls of both ventricles and the posterior septum, running with the PDA in the posterior interventricular groove

**Into**
Right end of the coronary sinus, near its opening into the [right atrium](https://durgical.com/en/anatomy/right-atrium/)

## Relations

**Below**
Diaphragmatic surface of the heart, resting on the central tendon of the [diaphragm](https://durgical.com/en/anatomy/diaphragm/)

**Deep**
Posterior (inferior) part of the [interventricular septum](https://durgical.com/en/anatomy/interventricular-septum/)

## How to find it

Seen when the heart is lifted to expose its diaphragmatic surface: it runs up the posterior interventricular groove beside the posterior descending artery and ends in the coronary sinus a short way from its opening into the right atrium.

## On imaging

Coronary sinus venography and CT venography show it climbing the posterior interventricular groove from the apex to the sinus.

## Common problems

- Rarely a problem on its own.

## Clinical notes

- Because the posterior descending artery runs right beside it, ablation inside the vein carries a risk of injuring the artery
- Because it joins the sinus so close to the ostium, a retrograde cardioplegia balloon placed deep in the sinus can sit beyond its opening and leave the inferior wall and septum less well protected

## Anatomical variants

- It may open directly into the right atrium instead of the coronary sinus
- A coronary sinus diverticulum near its entry is associated with posteroseptal accessory pathways

## Test yourself

Think of the answer, then tap the question to see it.

## In which groove does the middle cardiac vein run, and with which artery?

The posterior interventricular groove, beside the posterior descending artery.

## Where does the middle cardiac vein enter the coronary sinus?

At its right end, close to its opening into the right atrium, so it is the first large tributary a catheter meets.

## Why does ablation inside the middle cardiac vein carry a risk to the coronary circulation?

The posterior descending artery runs right beside the vein and can be injured.

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Educational information, not medical advice. For any symptom, see a health professional.

## Its names

**Official Latin (TA2)**
vena media cordis TA2 4165

**Official Spanish (DeCS)**
Vena cardíaca media

**English (TA2)**
Middle cardiac vein

**Also called**
posterior interventricular vein · inferior interventricular vein · vena cordis media · vena interventricularis dorsalis cordis

## Related

- [Coronary sinus](https://durgical.com/en/anatomy/coronary-sinus/)
- [Posterior descending artery (PDA)](https://durgical.com/en/anatomy/inferior-interventricular-artery/)

Sources: Terminologia Anatomica (TA2); [Anatomy, Thorax, Heart Veins](https://www.ncbi.nlm.nih.gov/books/NBK549786/); [Anatomy, Thorax, Coronary Sinus](https://www.ncbi.nlm.nih.gov/books/NBK557566/).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/anatomy/middle-cardiac-vein/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/middle-cardiac-vein/