My Husband Has Been Having A Racing Heart. We Went

My husband has been having a racing heart. We went to our family doctor and he told him how to stop it from racing. This has been going on once every 3 months or so but it seemed to race for a short time then quit. Now since Thanksgiving it has been going it more. Now the last 2 weeks it has been doing it aff and on all day long. He has felt that his heart has been stop pumping for about 10 to 20 seconds at a time also. Is this something to worry about? Is he having a stroke? Or heart atach? I don't know what to do?