The left atrium is one of the four chambers of the heart, located on the left posterior side. Its primary roles are to act as a holding chamber for blood returning from the lungs and to act as a ...

And it’s all to do with the four different chambers in your heart – and where each side of the heart pumps blood to. There are two atrium (left and right), in the upper part of your heart.

ST elevation in the posterior leads of a posterior ECG (leads V7-V9). Suspicion for a posterior MI must remain high, especially if inferior ST segment elevation is also present.