Pain, numbness and tingling of the left arm may signal a cardiac emergency. Photo Credit: Comstock Images/Stockbyte/Getty Images The person walking into an emergency room with symptoms of pain, numbness and tingling in the left arm should be prepared for a series of tests to rule out a heart problem. This is not because a heart problem is the most common cause of these symptoms, but because it is the most serious of the possible causes, and the one that demands immediate medical treatment.