While at rest, just sitting on my couch working on my homework, I felt my heart start beating very hard and vast for a few seconds. My chest inside felt hot, or warm during this time. It seemed like my heart perhaps skipped a beat or the beats were overlapping. It was enough for me to be stunned, I grabbed my chest... my heart rate back to normal, but I notice my lips feel kind of tingly. I know it was not a panic attack as I have had those and this was different. I was diagnosed with a heart murmur when I was an infant but grew out of it by the age of 8.