Doctor Decoded: What the Heck Is Arrhythmia?

You can’t spell arrhythmia without rhythm, and that’s no coincidence.

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Your doctor says your heart has an arrhythmia, and she might need to run more tests. Wait a sec—rewind. Arrhythmia?

You can’t spell arrhythmia without rhythm, and that’s no coincidence. Arrhythmia means the heart is beating abnormally—that is, it’s lacking its rhythm.

Normally, a healthy heart beats to a stable rhythm. These beats are contractions of the different chambers of the heart, which are initiated by electrical impulses. These are controlled by the sinoatrial node, which is often dubbed your “natural pacemaker.”

Normally, the average heart beats 60 to 100 times a minute, which helps push nutrient-rich blood throughout the body in a steady, consistent manner. When you’re stressed or you’re exercising, the sinoatrial node tells your heart to speed up in order to amp up blood flow; when you’re at rest, the heartbeat slows down.

But if you have an arrhythmia, your heart may beat too slow, too fast, or just erratically, even when you're at rest. There are many different types of arrhythmias, but the basic categories include:

  • Tachycardia: When the heart beats too fast. This is a problem because the heart beats before the chambers even fill with blood.

  • Bradycardia: When the heart beats too slow. This deprives the body of oxygen-rich blood.

  • Atrial fibrillation: When the heartbeat is irregular and out of sync. This results in abnormal blood flow, and it increases the risk of clots and stroke. Atrial fibrillation is often described as a “fluttering” feeling in the heart.

Because an abnormal heartbeat affects your blood circulation, an arrhythmia may produce effects such as lightheadedness, shortness of breath, or fainting.

If your heart is on the fritz, your doctor will probably want to figure out why. Arrhythmia is a symptom—not a condition—so it could be a sign of underlying problems such as coronary artery disease, substance use disorders, anxiety disorders, electrolyte imbalances, or heart failure. Learn more about what your heart rate means for your health here.