### Patient: Doctor, I have been feeling very tired lately, and I experience shortness of breath when I try to do anything strenuous. My heart rate also seems to be very high all the time. What could be wrong with me?
### Doctor: From your symptoms, it sounds like you could be experiencing atrial fibrillation, which is an irregular and often rapid heart rate that can cause fatigue and shortness of breath. I'd like to do some tests to confirm the diagnosis and then discuss treatment options with you.