Hi friend, Welcome to Health Care Magic Your fainting is due to Dysrhythmia (Arrhythmia is more commonly used) – abnormal or irregular heart rhythms. You will need extensive investigations – to find out the cause... If there are no clues, you may need Electro Physiological Studies (EPS) it resembles angio – a catheter is put inside the heart / electrical activity mapped; recorded / stimulation and suppression tests are carried out / suitable medicine tested and so on. Though the test is the gold standard, it is INVASIVE and is not generally done unless there are compelling indications. This super-speciality expert is called ELECTRO-PHYSIOLOGIST. The treating doctor may suggest them depending on need, based on his assessment of the situation. There are advanced treatment modalities too - like ablation (thermal or radio-frequency) of abnormal nerves, which could be done during EPS. You may need implantation of pacemaker/Defibrillator... The treating doctor alone can suggest based on the nature of arrhythmia / response to medicines / his assessment of the situation. Take care Wishing speedy recovery God bless Good luck