A fainting lady with some extrasystoles

A30-year-old woman presents with repeated syncope. Her symptoms started a few months ago without a particular trigger. The repeated episodes are not preceded by triggers either. Occasionally she experiences some palpitations followed by dizziness or syncope. She feels healthy otherwise, has no relevant medical history and is not taking any medication. Physical examination reveals no abnormalities, nor does laboratory investigation or echocardiography. Her ECG is presented: leads II, III, aVF, and V4 to V6 are shown, calibration is given in the margin. What is your diagnosis and what would your treatment be?