Add Yahoo as a preferred source to see more of our stories on Google. You're curled up on the couch, finally relaxing after a long day when suddenly, your heart starts racing. You're obviously not ...

Have you ever experienced a sudden increase in heart rate while sitting, lying in bed or even during a calm moment at work? The feeling can be unsettling as it often comes without warning or a clear ...

Everybody has natural rhythm. Call it your inner drummer--the heartbeat keeps time for the rest of the body. But what happens if your beat's too fast or slow? In medical terms, that's called cardiac ...