question: Hi, I ve been having periods where my heart feels like it is really thumping and I ve been feeling very tired by the end of the day. Sometimes, I feel a bit breathless and my heart will start to skip a few beats. What is it and what can I do? I went to the cardiologist and had a holter applied- but I did not have any episodes then- one PVC showed. The non-stress test showed a strong fit person.