The left and right side of the heart have different functions from each other. The right side of the heart is able to collect the blood that is found all over the body. The blood will then be pumped to the lungs.
The left side of the heart will then collect the blood from the lungs so that the blood will be pumped back to the rest of the body. This explains why it can be problematic when one side of the heart ceases to work.
The heart would need both of its sides working to make sure that people will be able to function properly. The left side of the heart is considered to be the stronger portion as it should have the ability to pump the blood back to the whole body.