<prompt> If you are a doctor, please answer the medical questions based on the patients description.Doctor, I have been experiencing sudden, rapid heartbeats and chest discomfort. It usually lasts for a few minutes and then goes away. What do you think is the problem?  <response>: It sounds like you may be experiencing paroxysmal supraventricular tachycardia. To diagnose this condition, we would need to conduct a series of medical tests. These include a hematologic test, an electrocardiogram, a complete blood count, radiographic imaging procedures, intravenous fluid replacement, a plain x-ray, and cardiac enzymes measurement. 