There are many types of arrhythmias, depending on what part of the heart is affected and whether they cause a slow, fast, or irregular heart rate. Arrhythmias may happen in the atria (upper chambers of the heart) or the ventricles (lower chambers of the heart).
Arrhythmias that cause a slow, fast, or irregular heartbeat
- Bradycardia is a resting heart rate that is slower than 60 beats per minute. Some people, especially people who are young or physically fit, may normally have slower heart rates. If you have a slow heart rate, your doctor can find out whether this is normal for you.
- Tachycardia is a resting heart rate that is faster than 100 beats per minute. You may also have an irregular heartbeat.
- A premature or extra heartbeat happens when the signal to beat comes too early. This creates a pause, which is followed by a stronger beat when your heart returns to its regular rhythm. It can feel like your heart skipped a beat. This is a common type of arrhythmia, and it can cause other types of arrhythmias.
This type of arrhythmia starts in the atria or the gateway to the lower chambers.
- Atrial fibrillation is the most common type of arrhythmia. More than 2.5 million people in the United States have atrial fibrillation. This condition causes your heart to beat more than 400 beats per minute. Also, your heart’s upper and lower chambers do not work together as they should. When this happens, the lower chambers do not fill completely or pump enough blood to your lungs and body.
- Atrial flutter can cause the upper chambers of your heart to beat 250 to 350 times per minute. The signal that tells the atria to beat may be blocked by damaged or scar tissue. This may cause the upper chambers and lower chambers to beat at different rates.
- Paroxysmal supraventricular tachycardia (PSVT) causes extra heartbeats because of a problem with the electrical signals that begin in the upper chambers and travel to the lower chambers. This type of arrhythmia begins and ends suddenly. It can happen during vigorous physical activity. It is usually not dangerous and often happens in young people.
Ventricular arrhythmias start in your heart’s lower chambers, called the ventricles. These arrhythmias can be very dangerous and usually require medical care right away.
- Ventricular tachycardia is a fast, regular beating of your ventricles that may last for only a few seconds or for much longer. A few beats of ventricular tachycardia often do not cause problems. However, if this lasts for more than a few seconds, it can lead to more serious arrhythmias, such as ventricular fibrillation (v-fib).
- Ventricular fibrillation occurs if electrical signals make the ventricles quiver instead of pumping normally. Without the ventricles’ pumping blood to the body, cardiac arrest and death can happen within a few minutes.
How do you know if your heart beats too fast or too slow?
Most adults have a resting heart rate of between 60 and 100 beats per minute. Some smartwatches or smartphone apps can help you find out your resting heart rate. You can also find out your heart rate by feeling your pulse.
To find your pulse, gently place your index and middle fingers on the artery found on the inner wrist of either arm, below your thumb. You should feel a pulsing or tapping against your fingers. Watch the second hand or set the timer on your stopwatch or phone and count the number of beats you feel in 30 seconds. Double that number to find out your heart rate or pulse for 1 minute.