Suggest Treatment For Heart Palpitations

Hello, Over the past 6 weeks I have been having heart palpitations, along with rapid heart rate (90-110 resting) and hand tremors. I am an otherwise healthy 29 yr old women. I saw my dr and he did ekg and labs. My blood work came back normal, and my ekg showed incomplete rt bundle branch block. I just saw a cardiologist today, and he ordered a holter monitor and echo. He doesn't seemed concerned with my symptoms. He listened to my heart rate sitting (in the 80's) then had me stand quickly and it jumped up past 100. He says this makes him think I may be lacking sodium?? He says I should eat more salty foods. I feel like I do, however, I watch my intake and aviod salt when possible. I really don't think I am lacking salt in my diet. Do you think the lack of over salted foods could cause these symtoms suddenly? Thank you...