Two days ago, I was bitten by a mosquito twice on each leg by my knee. My feet and ankles started to swell about an hour later. The next morning, they were swollen much more. If I elevated my feet, the swelling goes down. As soon as I stand, the swelling comes back. I thought this had to do with a bug bite because of the timing of it. But, since I have MVP (Mitral Valve Prolapse) and heart palpitations, I'm concerned of heart failure. I have an appt. with my doctor in two weeks, but am wondering if I should go to emergency. I'm not too sure that emergency can actually diagnose this.