The stress of planning can sometimes cause palpitations, but it shouldn't directly block conceiving. However, please be very gentle with yourself and get a doctor's opinion for safety.
My doctor mentioned that minor palpitations are normal due to anxiety, but a consistently high resting heart rate can indicate anemia or thyroid issues. Please get a proper blood check done.
Fast heartbeat or palpitations can be due to thyroid issues or anxiety, which might indirectly affect your cycle. Get a thyroid test and ECG done to rule out medical issues.
Personally, I had rapid heartbeats during anxiety attacks when we were trying to conceive. I didn't take any medicine but talked to my doctor, and it turned out to be normal stress.
Now that my baby is a toddler, I realize how much stress I took back then. Fast heartbeat can just be stress, so try to calm down and consult a doctor once.
High heart rate can occur if you are over-exercising or stressed. Take a break, do only light walks if doctor allowed, and monitor your vitals properly.