A fast heartbeat can be caused by emotions like stress or anxiety. Dehydration, or drinking caffeine or other stimulants, can ...

A new study shows that the sinoatrial node (SAN) -- a small but powerful structure in the human heart that serves as its natural pacemaker and initiates every normal heartbeat -- runs on different ...

You know the feeling. When you first see your crush and your head starts spinning, your palms get sweaty, and your heart begins beating a mile a minute. Is this love? Or is it … an arrhythmia? The ...

The heart is the body's hardest-working muscle. Whether you're awake or asleep, or exercising or resting, your heart is always at work. It pumps blood through arteries to deliver oxygen to organs and ...