Can a viral infection cause temporary pounding heart? my husband had a virus and his heart would beat so hard you could see him move with it. it cleared up after the virus cleared. he was also dehydrated?

Dehydration causes low blood pressure, which the body tries to compensate for by increasing the heart rate. This can often be seen or felt like a pounding heart. Most probably, this whole episode was caused by the viral infection, which can cause excess fluid loss through fever, diarrhea, lack of apetite, and its resolution indicates that your husbands system went back to normal.