### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
why does my heart skip beats or "flubber" when sitting?  very rarely does it happen when standing... been to my dr. and she feels it stress (I agree to a point) but its only when I am sitting.  I also have been diagnosed with neurocardiogenic syncope like 12 yrs ago. So I do take a beta blocker twice a day....

### output:

Dear Patient, Thank you very much for your question. According to your description you may be having a condition called Extrasystoles or premature heart beats. Premature heart beats are divided into premature atrial contractions (PACs) or premature ventricular contractions(PVC's). In most cases, PACs are benign and no need of treatment. If you have occasional PVC's and you are very healthy, no need of treatments, however, it is needed to monitor your heart function to rule out how often they occur.  The only way to rule out your heart function is taking an ECG test. My recommendation for you to visit your family doctor again and explain all your complaints. Your family doctor will direct you to an ECG test, Holder monitor test(24 hour ECG record), Exercise ECG and blood tests to diagnose your condition.  In your case, I believe holder monitor test can be very useful to make a diagnosis because it is being highly informative compared to standard ECG testing to rule out heart rhythm disorders due to its 24-hour monitoring. As you mentioned, for your neurocardiogenic syncope the underlying cause may be a heart rhythm disorder, therefore, I advise you to visit your family doctor again and do further test which may help not only to diagnose your condition properly, but also to treat your condition correctly. If necessary only your physician will then direct you to a consultation of a Cardiologist. I hope that I answered your question. Good luck!