I've been suffering from tachycardia for the past few months now, with heart rates reaching up to 170-180. The past few days, I've been suffering from left sided chest pain, increased sweating and shortness of breath even when I'm at rest doing nothing. I went to the ER today and they ruled out heart attack and pulmonary embolism. I had labs drawn for another doctor and my CRP level was 19mg/L and my white blood cell count has slowly been going up the last few times I've gotten my CBC checked. On my CT scan they did today in the ER, it does mentioned they found " residual thymic tissue"....... A few times over the last few months, I've had episodes where I felt like my heart had been "shocked with a defibrillator machine" and it woke me up out of a dead sleep...... If anyone has any insight in what this could be, that would be great!