This Month I Have Had 2 Episodes Of Times I

This month I have had 2 episodes of times I was sitting still and all of a sudden felt a warm tingling sensation in my hands then it faded to a quick fast and rapid heart beat. The racing heart beat can also be observed by a fast pulse in my neck and other areas. The first episode lasted 45 min and the 2nd 10 min. What may be causing this? I did not have panic nor anxiety prior to incidents.