“Can you have heart failure and not know it?”

Depending on the type of heart failure it is possible.

Thanks for the question! Usually there are some associated symptoms such as shortness of breath, dizziness, light headedness, swelling, fatigue. As you can imagine, those symptoms can be from a variety of ailments. If you are not feeling well the best advice would be to go to a local clinic or ER, or contact your primary care physician for an appointment. Good luck and hope you feel better soon!

Typical symptoms are decreased levels of activity. You may not really think that getting tired after a flight of stairs or walking a block or two is your heart. Also you may notice that when you take your socks off that you have a band around your legs. That's a sign of fluid retention. As for sudden heart failure, that may be what is known as an angina equivalent. In any case see your doctor.