Heart - Cardiology & Cardiovascular Surgery

Types of Arrhythmias

At Mount Sinai Fuster Heart Hospital, we treat many types of irregular heartbeats, or arrhythmias. These disorders of the heart's normal rhythm can result in rapid heart rates, slow heart rates, or irregular heart rates. You might experience heart flutters, palpitations, loss of exercise tolerance, shortness of breath, or fainting. Some arrhythmias are not dangerous, but others require prompt care. At Mount Sinai Fuster Heart Hospital, the concerns we see most often include:

Atrial Fibrillation

Atrial Fibrillation, also called AFib, is the most common form of arrhythmia and occurs more frequently as we age. It happens when the upper chambers quiver rather than beating regularly and effectively. People with AFib often experience palpitations, fatigue, chest discomfort or shortness of breath. However, some people may not feel any symptoms, and we often discover it during a routine check-up.

Left untreated, Atrial Fibrillation is a leading cause of stroke and can weaken the heart and cause heart failure. Treatments include medications, cardiac surgery, ablation, and implantable devices. Women may respond differently or have different side effects from the drugs that are used to treat arrhythmias.

Episodes of atrial fibrillation may come and go (called paroxysmal atrial fibrillation) or they may continue for longer periods of time (persistent atrial fibrillation). Typically, AFib lasts for up to 24 hours; when an episode lasts more than 7 days, we call the condition persistent atrial fibrillation.

Atrial Flutter

Atrial flutter is similar to atrial fibrillation, though the fast heartbeat can be more regular. Many people with atrial flutter develop atrial fibrillation over time. Atrial flutter can also make it harder for your heart to push blood into your ventricles, which are the lower chambers of your heart. That, in turn, means your heart sends less blood throughout your body. Symptoms include a fluttering feeling in the chest, palpitations, pressure in the chest, shortness of breath, anxiety, lightheadedness, and fainting. This condition increases the risk of stroke and heart failure.

Atrial flutter can be chronic or it can come and go. We treat it by slowing down the electrical impulses that go from the top chambers of the heart to the bottom ones. To do this, we prescribe medications and use an external defibrillator to administer electrical shocks. More of the time we perform catheter ablation therapy, a non-surgical catheter procedure that can cure a patient of this rhythm.


Also known as a slow heartbeat, bradycardia may stem from problems with the heart's electrical system. It can be caused by aging, electrolyte abnormalities, medications, and abnormal thyroid function. Sometimes this condition occurs in athletic individuals or those taking medications. A slow heart rate can cause fatigue, dizziness, and fainting. We typically treat symptomatic bradycardias with the implantation of a pacemaker.


Tachycardia, or a fast heartbeat, can have many causes. The heart normally beats faster with physical activity or emotional stress, but if the heart races at other times or for a prolonged period, you should have it evaluated. Tachycardias are grouped by the chamber from which they originate.  Supraventricular arrhythmias, for instance, start in the upper chambers of the heart (the atria) and include atrial fibrillation (A-fib), Atrial Flutter, supraventricular tachycardia (SVT), and Wolff-Parkinson-White (WPW) syndrome.

Supraventricular Tachycardia

Supraventricular Tachycardia, also called SVT, is usually caused by either an abnormal electrical circuit or rapidly firing cells in the upper chambers of the heart. SVT can last anywhere from a few seconds to several hours. Symptoms can include palpitations, lightheadedness, pounding of the chest, and shortness of breath – especially while exercising. Episodes generally are not life threatening but can be bothersome and debilitating. We often treat SVT with an ablation procedure.

Ventricular Arrhythmias

A Ventricular arrhythmia is a condition which originates in the lower chambers of the heart (ventricles). We usually find the problem when we hear three or more beats in succession coming from one of the ventricles. We consider the arrhythmia to be sustained if it lasts more than 30 seconds. Sustained ventricular arrhythmia keeps the lower heart chambers from being able to maintain proper blood flow throughout your body. The condition can lower your blood pressure and cause heart failure.

Ventricular arrhythmia can cause heart palpitations, shortness of breath, fainting, lightheadedness, chest discomfort, and pale skin. It can be tricky to diagnose this condition as it often occurs in emergency situations. Treatment options include cardiopulmonary resuscitation, defibrillators, medicines, catheter ablation procedures, and open heart surgery. Sometimes we install an automatic defibrillator into your heart to deliver shocks as needed, to keep your heart beating steadily.

Wolff-Parkinson-White Syndrome

Some people are born with an extra electrical pathway between the top and bottom chambers of the heart, which we call Wolff-Parkinson-White Syndrome (WPW). This condition causes abnormal circuits to form and leads to a fast heart rhythm. We usually find this syndrome during a routine electrocardiogram. It can be dangerous even if you experience no symptoms. We often treat WPW with an ablation procedure.

Ventricular Arrhythmias

There are two types of ventricular arrhythmias, which are abnormal heartbeats in the lower chambers of the heart (called ventricles). The first type, ventricular tachycardia, is a fast heart rhythm that can cause dizziness, palpitations, and fainting. Ventricular tachycardia is often associated with coronary artery disease and other heart problems and requires prompt medical attention.

The second type of ventricular arrhythmia, called ventricular fibrillation (VF)is a medical emergency. The electrical signals in the lower chambers become erratic and the heart stops beating. If not treated immediately, VF can result in sudden death.

Premature Beats

Premature beats are early, extra heartbeats, often called "skipped beats." Premature beats can arise from the upper or the lower chambers of the heart. While normally not dangerous, they can be associated with other heart diseases or predict future cardiac problems or arrhythmias. The condition can be aggravated by smoking or an excess amount of caffeine. Treatment may be necessary if you frequently experience premature beats, or if they cause symptoms.

Ventricular Premature Complexes

Ventricular premature complexes (VPCs) are single beats that disrupt the usual sequence of heart beats. The frequency of VPCs may occur very infrequently or thousands of times a day. Regardless of the trigger, VPCs can indicate possible heart dysfunction and you should have the condition evaluated.  While most people don’t feel VPCs, some do experience palpitations or fluttering in the chest, especially when at rest and when lying on their backs.

Atrial Premature Complexes

Similar to VPCs, atrial premature complexes involveextra heart beats that occur alone or in series. Symptoms, also, are similar to ventricular premature complexes.

Sick Sinus Syndrome

Sick sinus syndrome occurs when the heart’s ‘natural pacemaker,’ called the sinus node, malfunctions. As a result, the heart rate slows, which can lead to fatigue, dizziness, and fainting. This condition generally affects people over 65 years of age.