Arrhythmia is an irregular heartbeat caused by abnormal electrical impulses in the heart. Scary as it sounds—heart beating too slowly, too quickly, or skipping a beat—arrhythmia is not uncommon and often harmless. Some arrhythmias, however, can increase the risk of stroke, blood clots, and cardiac arrest, and are more serious for those with heart failure or heart disease. Arrhythmia symptoms can include dizziness, lightheadedness, or shortness of breath.

What Causes Arrhythmia?

Read how a racing heartbeat can signal a bigger problem

Can Drugs Treat Arrhythmia?

They can be effective, but watch out for the side effects

Living With a Defibrillator

You don't really notice it until it goes off—then you get the shock of your life

Why Her Heart Gallops

What she goes through when her heart races to 180 beats per minute