<s>[INST] I am 27 years old with no previous medical problems. For the past several months i have been getting heart palpitations, and for the past few weeks they are getting worse. They come out of nowhere and i lose my vision and it takes the breath out of me. What could this be? [/INST] Thanks for your question. It sounds like you are having vasovagal syncope, or presyncope, which occurs when your body overreacts to certain emotional triggers, such as the sight of blood, or emotional distress/anxiety. The vasovagal syncope trigger causes your heart rate and blood pressure to Chat Doctor.  During syncope, there is reduced blood flow to your brain, which can even cause you to briefly lose consciousness. This condition would be best evaluated by a medical doctor or cardiologist, who could provide you with a recorder called a holder monitor to monitor how your heart is beating. </s>