<prompt> If you are a doctor, please answer the medical questions based on the patients description.Hello, I have been noticing palpitations in my chest with a sudden light headed feeling and sharp pain in my head when this happens. I almost fell over last night when this happened. Should I be concerned? I was last checked for heart palpitations in 2006. Had a stress test and EKG which all turned out normal. I am hypothyroid and on armour...just put on it five weeks ago. No other meds or health conditions that i am aware.  <response>: Hi AS you are hypothyroid you must be on thyroxine, go get you thyroid profile measured asap, as higher THS can also cause severe palpitations. Presyncope is a state of lightheadedness, muscular weakness, blurred vision, and feeling faint as opposed to a syncope, which is actually fainting. Presyncope is most often cardiovascular in etiology. Fot this 2d echo of the heart and a carotid Doppler is advice to rule out the left ventricle functions. Plpitations-Palpitations are feelings or sensations that your heart is pounding or racing. They can be felt in your chest, throat, or neck. You may: Have an unpleasant awareness of your own heartbeat. Palpitations can be because of life-threatening arrhythmias also hence a 24 hour holder monitoring should be done to find out the nature of the beats thanks 