What Are Arrhythmias?
Arrhythmias are abnormal heartbeats usually caused by an electrical "short circuit" in the heart.
The heart normally beats in a consistent pattern, but an arrhythmia can make it beat too slowly, too quickly, or irregularly. This can cause the heart to pump inconsistently, leading to symptoms like fatigue, dizziness, and chest pain.
What Causes Them?
Your heart has its own electrical system that sends electrical signals around the heart, telling it when to contract and pump blood around the body. The electrical signals start in a group of cells, called the sinus node, located in the right atrium. The sinus node is the heart's pacemaker and makes sure the heart beats at a normal and consistent rate. The sinus node normally increases your heart rate in response to exercise, emotions, and stress, and slows your heart rate during sleep.
But sometimes the electrical signals don't "communicate" properly with the heart muscle, and the heart starts beating in an abnormal rhythm — this is an arrhythmia (also called dysrhythmia).
Arrhythmias can be congenital (meaning a person is born with one) or happen later, and they can be temporary or permanent.
Arrhythmias also can be due to chemical imbalances in the blood; infections; diseases that irritate the heart; medicines (prescription, over-the-counter, and some herbal remedies); injuries to the heart from chest trauma or heart surgery; use of illegal drugs, alcohol, or tobacco; caffeine; and stress. Arrhythmias also can happen for no apparent reason.
Signs and Symptoms
Arrhythmias make the heart beat less effectively, interrupting blood flow to the brain and the rest of the body. When the heart beats too fast, its chambers can't fill with enough blood. When it beats too slowly or irregularly, it can't pump enough blood out to the body.
If the body doesn't get the supply of blood it needs to run smoothly, a person might have:
- dizziness
- fatigue
- lightheadedness
- weakness
- palpitations (a feeling of fluttering or pounding in the chest)
- shortness of breath
- chest pain
- fainting
Arrhythmias can be constant, but usually come and go at random. Sometimes arrhythmias can cause no symptoms at all — in these cases, the arrhythmia is only found during a physical exam or a heart function test, like an electrocardiogram (ECG/EKG).