Hi stephleonidas , i would like to have some additional information from you like your age ? are you currently suffering from diseases like diabetes
? Since how long are feeling your " odd heart beat " and the frequency ? Do you smoke ? Did you ever get diagnosed for a lung problem or breathlesness ? . an isolated finding of a left atrial abnormality in an electrocardiography
is too inconclusive . If your answer is "yes" you smoke , have breathlessness & you do have hypertension either on medicines or not then better seek opinion from a cardiologist. If your answer is " yes" that you have been diagnosed with a lung problem or occasionally have breathlessness then please do seek an opinion from a chest physician . Hope i have been able to throw some light on your problem. Take care.