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).