I have a portable ecg and it is showing that i am in tachycardia. my heart rate is 222 at rest. do i need to go to the emergency room? i started a new thyroid medication on wednesday and i am thinking that this is what is causing it but not sure?

If your heart rate is truly 222 beats per minute, you need to go to the nearest emergency room immediately. I wonder if your machine is accurate since at that high a heart rate, you would likely be experiencing symptoms-like lightheadedness, shortness of breath, chest discomfort, etc. If you are experiencing any of these symptoms and/or your heart rate is really that high, please go to the ER NOW!

You have to feel chest palpitation +/- shortness of breath with that heart rate (HR). If yes, go to ER. In the mean time, you can try Valsava maneuver to see if HR comes down (Take a very deep breath then bear down and hold your breath like straining when trying during bowel movement). If you have no symptoms at all, check the HR by feeling the neck pulse and count the rate for 1 minute.