by EBSCO Medical Review Board

There are many types of heart arrhythmias. The type will depend on what part of the heart the problem starts in.

Premature (Early) Contractions

The signal to start a beat comes from the heart muscle instead of the nerve pathway. This makes that area of muscle beat before it should. It will spread through the rest of the heart and make it beat out of the normal rhythm. Most people will have a premature contraction at some point in their lives. If they happen rarely they are harmless. At most, they can cause a flutter, a skipped beat, or jumping in the chest. However, those that happen more often can cause problems with blood flow through the heart. It can also cause problems for people with heart disease. In this case, premature contractions may need to be watched or treated. They may be caused by changes in the heart. It can also be caused by stress, caffeine, or nicotine.

The types of premature contraction will depend on where it starts. These include:

Premature Supraventricular Contractions

Premature supraventricular contractions begin in the upper parts of the heart. They may also be called premature atrial contractions (PAC). The early beat in the upper heart can make it hard for the heart to fill with blood.

Premature Ventricular Complexes (PVC)

PVCs start in the lower parts of the heart. They may feel like there is a pause before the next heartbeat. Early beats here can affect how much blood goes out to the body.

Sinoatrial Node (SA) Arrhythmias

The SA node keeps the heart beating at 60 to 100 beats a minute. Problems with the SA node can lead to:

Sinus Arrhythmia

A sinus arrhythmia is a change in the signal to SA node. The vagus nerve sends signals to the node. In some people, the vagus nerve is set off when you breathe in. This makes the heart rate go up when you breathe in and decrease when you breathe out. It can be found in children and adults. For most, it does not cause any harm.

Sinus Tachycardia

Tachycardia is a heart rate faster than 100 or more a minute. It’s normal during physical activity or when you feel stress. However, the fast rate may start or continue when it's not needed. In this case, it is caused with stimulation to the SA node. Caffeine, nicotine, or certain medicines can overstimulate the SA node.

Sick Sinus Syndrome

Sick sinus is an SA node that is not working as it should. It doesn't create a healthy, steady rhythm of heart beats. It may cause a heart rate that's too slow, too fast, or one that switches between the two. Sick sinus can also cause long pauses in rhythm. The risk for sick sinus goes up as you get older. A pacemaker may be needed to create a healthy heart rate.

Supraventricular Arrhythmias

Arrhythmia of the upper chambers of the heart include:

Atrial Fibrillation (AFib)

AFib is the most common type of arrhythmia. It's a fast and erratic beating of the upper parts of the heart. The area looks like it's quivering. AFib can happen in short bursts. Some may last longer which will affect blood flow. If the upper chambers are beating too fast, it can't help to fill the lower heart with blood. The lower heart will then have less blood to pump out to the body and lungs. AFib doesn't always cause symptoms. Some may feel palpitations. Steady or severe AFib can cause breathing problems, lightheadedness, or mild cognitive impairment.

People with AFib also have a higher risk of stroke or heart attack. The slower flow of blood through the heart can let blood pool. This increases the chance of blood clots. These clots can travel to the brain or heart and cause a stroke or heart attack. Regular AFib also makes the heart work harder. Over time, this can lead to heart failure.

Atrial Flutter

A second type of fast rhythm in the upper heart is called atrial flutter. Unlike AFib, atrial flutter has a steady rhythm. The risks and problems are the same as AFib.

Paroxysmal Supraventricular Tachycardia (PSVT)

In PSVT, different areas of the upper heart stimulate a faster than normal heart rate. It can cause periods of very fast heartbeats that start and end without warning. PSVT may be brief. This type may not need treatment. Other PSVTs are steady and ongoing. These can lead to chest pain or lightheadedness, and weakness. Regular PSVTs may need to be treated.

Ventricular Arrhythmias

Ventricular arrhythmias happen in the lower part of the heart. Arrhythmias in the lower heart can be very serious. They affect blood flow to the body and lungs. Untreated, they may lead to sudden cardiac arrest or death. Types of ventricular arrhythmias include:

Ventricular Fibrillation (VFib)

VFib is a very fast and erratic beating of the lower heart. This causes the heart to quiver. It becomes impossible to pump blood to the rest of the body or lungs. VFib is a main cause of sudden cardiac death.

Ventricular Tachycardia (VTach)

VTach is faster than normal heart rate. It's normal during physical activity or stress. However, VTach that starts or continues when it wasn't needed can cause problems. The fast heartbeat makes it hard for the lower heart to fill with blood between heartbeats. This means there is less blood that can be pumped out to the body.

Long QT Syndrome

QT is the name given to a section of an EKG reading. It shows the electrical activity of the lower part of the heart. In long QT syndrome, the QT section is longer than it should be. This means there's a problem with how the electrical signal moves through the lower heart. The heart can't beat as it should. It can lead to fainting spells and palpitations.

Nerve Conduction Problems

Heart Block

Heart block is a stop in electrical activity through the heart. There may be no symptoms or it may cause your heart rate to slow down. A slower than normal heart rate can cause lightheadedness or fainting. The heart may also feel like it is skipping beats.

Wolff-Parkinson-White Syndrome (WPW)

WPW is an extra pathway for electrical activity. It can cause periods of faster than normal heart rate. It can lead to a number of other arrhythmias such as PSVT. WPW may cause mild to serious symptoms. Treatment will depend on symptoms.


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