You or someone else has symptoms like: central chest pain or discomfort in the chest that doesn't go away – it may feel like pressure, tightness or squeezing pain that radiates down the left arm, or both arms, or to the neck, jaw, back or stomach unconsciousness seizures or fitting difficulty breathing (snoring or rasping) rapid heart beat low or undetectable heart beat blue or pale tingling of knees, hands and lips chest pain and breathlessness, nausea, sweating or coughing up blood