Hi, Claudia,
Have you spoken with Chunyi about your heart? If you are in the Minneapolis area, you could set up an appointment. I am the person with the heart problem who spoke at the conference. I didn't realize how lucky I was until the conference. Justin and I practiced Level I at home for several months. We have taken all 4 Levels. I practice some parts of the Level I exercises each day, sometimes doing the exercises lying down, either when I go to bed or early morning. The first exercise will settle the rhythum of heart very quickly. Chunyi gave me some exercises to do to strengthen my heart. I do meditations almost daily. I feel you should talk to Master Lin first, whether it be by phone or appointment.