We looked it up, from what we saw, the Bi-Cuspid valve is congenital, it's supposed to be a Tri-Cuspid. This I'm sure you know.
Do you have fluid accumulation, often shows readily in your legs, usually shows up as indentable edema, push where the top of the sock line would be and hold for several seconds, if you pull your finger away and the imprint is substantially there, it a sign of edema. Alternately, it shows in the ankles.
My wife worked for doctors, including a cardiologist, she said that a specialist should have a doctor on call to handle the patients in the hospital and emergencies. Certainly, you have a right to speak with a doctor before your regular (new) cardiologist returns, your symptoms are profound, you need specific guidance. Sometimes you can call the doctor's office after hours, an answering service picks up, and you can tell them you need to speak with someone.
Do you know what your blood pressure is? If you're holding water (edema), it may be elevated, the doctor should consider your conditions and decide if you need a diuretic (water pill). This probably explains the weight gain. This is a decision that, in my opinion, needs taken care of before you new doctor returns from vacation.
My wife suggested that your family doctor may be an avenue as well for interim treatment. I requested that my family doctor call my cardiologist, which he did, and my family doctor detailed what the cardiologist suggested.
Last, but not least, the Emergency Room is an avenue. I'm not sure where you live, but many of the tests I had done here are in the computer, so that the E.R., specialist, and family doctor have instant access, it didn't have to be sent to them. If you are concerned, don't hesitate to be seen and tell them of your condition, symptoms, and concerns. They could admit you if warranted. If you know the hospital where your new cardiologists works through, it may help your overall care, or at least simplify it.