Iv had a feeling of palpitations, and on checking my pulse it is irregular, a slight feeling of loss of breath twice over the last 1 month. The first time it occurred I visited the hospital, they did an EKG and everything seemed to be fine. They ran some blood tests, which were also fine. I returned as an outpatient the following day and had an ultrasound on my heart. they found that the left atrium was 41mm in diameter. The doctor said it was slightly larger than normal, and I should have it checked every 6 months. They also put a portable EKG monitor on me for 24 hours, the results returned normal. The rest was fine. The second time was last night, it again only lasted for 5 minutes. But I am slightly concerned that it occurred again soon after the first time. Should I be worried and return to my GP? I am an active and healthy person, I exercise and do weight training daily. All of this only started to happen when I stopped drinking and smoking about 2 months ago! I also had my thyroid gland ultrasound, and blood test, and it cam back normal. Thankyou