Electrophysiology (Heart Rhythm Treatments)

At the Mount Sinai Heart Institute, patients with common and rare heart rhythm disorders receive advanced diagnostics and innovative treatments from a team of highly skilled electrophysiologists. Cardiac electrophysiology is a field of medicine devoted to the detection and treatment of heart rhythm disorders (arrhythmias), which affect more than 2 million Americans.

The Columbia University Division of Cardiology at Mount Sinai provides highly specialized care for
patients suffering with heart rhythm disorders, such as supraventricular tachycardia, atrial fibrillation
and ventricular tachycardia. Mount Sinai’s accredited echocardiography lab utilizes specialized 3-dimensional imaging to more accurately assess a patient’s risk of heart disease by revealing heart valve function, blood flow and coronary artery disease using noninvasive techniques. We have an electrophysiology lab equipped with state-of-the-art computer mapping systems to guide radiofrequency ablation, allowing our specialists to diagnose and treat a wider range of the most complex arrhythmias. Our team of experts is also experienced in all types of device management (pacemakers and defibrillators) and syncope (fainting) evaluations.


Normally, the heart beats at a steady rhythm to supply blood to the lungs and the rest of the body. An arrhythmia is a condition in which heartbeats may be irregular (fibrillation), too slow (bradycardia), too fast (tachycardia) or too early (premature), and interferes with normal circulation of the blood. Arrhythmias can be caused by problems with the heart’s electrical conduction system; structural problems in the heart or blood vessels caused by birth defects, heart disease or certain conditions; or induced by substances or drugs. Left untreated, heart rhythm disorders can cause a wide range of problems from dizziness and fatigue to stroke and even sudden death.


An arrhythmia may be present all of the time or it may come and go. Some people do not experience any symptoms, while others notice symptoms only when they are more active. Common symptoms that may occur when an arrhythmia is present include:

  • Chest pain
  • Disturbed sleep
  • Dizziness or lightheadedness
  • Confusion
  • Fainting
  • Fast pulse
  • Fatigue
  • Heart palpitations (sensation that your heart is pounding or racing)
  • Irregular heartbeats (fast or slow)
  • Paleness
  • Premature contractions (extra, early or “skipped” heartbeats)
  • Shortness of breath
  • Stroke
  • Sweating

Tell your primary care doctor or cardiologist if you experience any of these symptoms.


To diagnose arrthythmia, your doctor will first listen to your heart with a stethoscope and check your pulse. He or she may then ask you to wear a heart monitoring device, such as a holter monitor or loop recorder, to measure your heart rhythm over time. If abnormalities are present, the doctor may recommend procedures and tests that evaluate heart function. This includes:

Cardiac Catheterization

Cardiac catheterization refers to a group of procedures that are performed by inserting a thin, hollow tube (catheter) through the leg or arm and threading it into the heart. In patients with suspected heart rhythm disorders, this procedure allows doctors to perform tests that evaluate structural and electrical problems of the heart and circulatory system.

Coronary Angiography

Coronary angiography is a test that uses dye and special X-rays to show the insides of the coronary arteries, which supply blood to the heart. Doctors use cardiac catheterization to access the coronary arteries and inject the dye, which makes it possible to see blockages in the arteries.


An electrocardiogram (also called an EKG) is a test that checks for problems with the electrical activity of the heart. Electrode discs are attached to the arms, legs and chest of a patient to detect the heart’s electrical activity.


An echocardiogram is a test that uses sound waves to create a moving picture of the heart. A sonographer moves a smooth piece of equipment across the patient’s chest to create a clear picture of the structures of the heart.

Electrophysiology Study

An electrophysiology study, or EP study, is a test to determine whether there is a problem with a patient’s “electrical system” and, if so, how to fix it. Doctors use cardiac catheterization to access the heart and place electrode-tipped catheters on heart tissue. The electrodes measure the heart’s electrical activity and are able to pace the heart, identifying where the heart is having problems conducting electricity.


Atrial Fibrillation

Atrial fibrillation (AF) is the most common heart disorder, affecting more than 5 million Americans and millions more worldwide. AF is characterized by disorganized episodes of rapid, irregular beating of the heart’s upper chambers (atria), which is induced by electrical impulses. The severity of AF is measured by the symptoms they cause, the duration of episodes (how long each episode of irregular heartbeats lasts), how long the patient has experienced AF episodes, the size of the patient’s left atrium (which can enlarge over time) and presence of structural heart disease (abnormalities in the valves, vessels and other structures of the heart).

Symptoms of AF typically include fatigue, shortness of breath, heart palpitations, chest discomfort, rapid heartbeat and fainting. Many patients with AF are at increased risk of stroke. Many patients also experience an enlarged left atrium and other cardiovascular problems, such as structural heart disease or congestive heart failure.

Treatment for AF includes medication, cardioversion and radiofrequency ablation. Some patients with AF can have a slow heartbeat at times, which may be treated with a pacemaker. Mount Sinai also offers the innovative Hybrid Maze Procedure for patients with chronic AF and enlarged left atria, who are generally difficult to treat with medication and single catheter ablation treatments.

Atrial Flutter

Atrial flutter (AFL) is similar to atrial fibrillation. However, AFL is caused by a single electrical wave that circulates very rapidly in the upper chambers of the heart (usually the right atrium) in an organized pattern. People with AFL usually continue to have a steady heartbeat, even though it is faster than normal. Patients with AFL may not have any symptoms, or they may experience symptoms similar to atrial fibrillation. Treatment for AFL typically includes medication, cardioversion and catheter ablation.

Heart Block

Heart block is a condition characterized by an abnormally slow heart beat (bradycardia). It occurs when some or all of the electrical impulses from the upper chambers of the heart are not properly transmitted to the lower chambers of the heart. Symptoms of heart block may include fainting, dizziness, lightheadedness, chest pain and shortness of breath. Different types of heart block may require different treatments, depending on exactly which part of the conduction system is faulty. Treatment may include lifestyle changes to address other heart conditions, medication changes and pacemakers.

Long QT Syndrome

Long QT syndrome (LQTS) is an electrical disorder in which the heart cells take longer than normal to recover after each heartbeat. It can be a serious condition predisposing to sudden death that can be inherited, acquired after taking certain medications or caused by a combination of heredity and medications. Symptoms of LQTS include palpitations, rapid heartbeat and fainting. Treatment includes limiting physical activity, taking medications to prevent chaotic heart rhythm, avoiding medications known to cause prolonged Q-T intervals, implantable devices and surgery. Patients with LQTS may be susceptible to Torsades de Pointes, a type of ventricular tachycardia.

Sick Sinus Syndrome

Sick sinus syndrome (SSS) refers to a group of signs or symptoms indicating that the heart’s natural electrical pacemaker, the sinoatrial node, is malfunctioning. This often results in an abnormally slow heart beat at rest (bradycardia) or a heart beat that fails to speed up with activity or in response to adrenaline. Many people with SSS have no symptoms, while others experience fatigue, fainting, shortness of breath, chest pain, disturbed sleep, confusion and heart palpitations. Treatment for patients with SSS typically includes the insertion of a permanent pacemaker.

Sinus Tachycardia

Sinus tachycardia is a normal, harmless condition in which the heart rate increases with fever, excitement and exercise. It rarely requires treatment aside from treating the underlying problem, such as anemia, infection or hyperthyroidism. In rare cases, a condition called inappropriate sinus tachycardia can cause the heart to beat faster than it should without any underlying problem. Medication is typically used to slow heart rate in these cases. In some patients, sinus node ablation can be performed to decrease the heart rate.

Supraventricular Tachycardia

Supraventricular tachycardia (SVT) describes several types of fast heart rhythms that are caused by electrical problems in the upper chambers (atria) of the heart but are not typically dangerous. Patients with SVT usually have a rapid and steady pulse that is accompanied by heart palpitations, fatigue or shortness of breath that start suddenly and stop suddenly. Treatment options include medications or a catheter ablation.

Ventricular Fibrillation

Ventricular fibrillation is a life-threatening abnormality in the electrical rhythm of the nerves of the lower chambers (ventricals) of the heart. In this case, the rhythm is very fast and irregular, causing the heart to stop effectively beating and preventing blood from flowing to the brain and other parts of the body. As a result, blood pressure falls to zero and the patient falls unconscious. VF can happen during a heart attack (myocardial infarction) or be caused by previous heart damage or a genetic heart condition. Life-saving shock (defibrillation) must be delivered to the heart within minutes of a VF episode to restore a normal heart rhythm and blood flow.

Ventricular Tachycardia

Ventricular tachycardia (VT) is an electrical heart rhythm disorder characterized by a very fast heart rate. It is usually is seen in the setting of other serious heart disease and can be life-threatening. If VT does not stop on its own, it usually requires treatment with medication, electrical cardioversion, catheter ablation or implantation of a defibrillator. VT requires aggressive monitoring and treatment, as it can lead to ventricular fibrillation and sudden death.

Treatment Options

The underlying cause of an arrhythmia determines which treatment option will work best.

Lifestyle changes

Taking steps to prevent coronary artery disease may reduce your chance of developing an arrhythmia. This includes eating a heart-healthy diet, exercising regularly, not smoking and managing stress. It may also include taking a daily aspirin or other prescribed medication.


Defibrillation is a process in which an electronic device applies pulses of electrical energy when the heart suddenly loses its natural rhythym and slips into a dangerously fast, uneven or quivering pattern. Defibrillation is a way to restore the heart’s natural rhythm and can save the patient’s life, and can come from an automated emergency defibrillator (AED) machine or from an implanted defibrillator.


Antiarrhythmia drugs are a category of drugs used to suppress abnormal heart rhythms resulting from irregular electrical activity of the heart. There are many different types of antiarrhythmic drugs. Other types of heart drugs can also be used to treat arrhythmias. These include beta-blockers, which reduce the heart’s workload and heart rate, and calcium channel blockers, which reduce heart rate. There are also a variety of drugs used by doctors in an emergency situation to control an abnormal heart rhythm or restore a normal heart rhythm.

Cardiac Ablation

Cardiac ablation is a nonsurgical procedure used to ablate (destroy) faulty electrical pathways in the heart. At Mount Sinai, our electrophysiologists specialize in radiofrequency catheter ablation. In this procedure, our team of electrophysiologists and interventional radiologists use image guidance (such as X-ray, CT scan or ultrasound) to help them guide a thin, flexible tube called a catheter through the veins and into the heart. The tips of the wires are equipped with electrodes that measure the heart’s electrical activity and help identify areas on the surface of the heart that are diseased. Once those locations are identified, doctors use the electrodes to emit radiofrequency energy that destroys this tissue, increasing the chance for a cure.

Hybrid Maze Procedure

Mount Sinai was one of the first hospitals in the country to pioneer this minimally invasive surgical procedure to treat chronic and severe cases of A Fib. It blends surgical and electrophysiological techniques, resulting in a more comprehensive and effective approach. During the procedure, a cardiac surgeon blocks pathways in the heart that can cause an irregular heartbeat, while an electrophysiologist uses mapping technology to fill in any small gaps left from the surgeon’s work. Click here to learn more.

Lariat Procedure

This procedure is an option for A Fib patients at high risk for stroke, yet unable to take blood thinners. The Lariat device is used like a lasso to tie off the heart’s left atrial appendage, where clots often form, thereby preventing them from traveling to the brain and causing a stroke.  It involves minimally invasive access to both the inner (endocardial) and outer (epicardial) surfaces of the heart in order to tie off the appendage without leaving any device inside of the heart.


There are several implantable medical devices to control and correct arrhthymias.


A pacemaker is a small device that is implanted inside the chest to prevent the heart from beating too slowly. It uses low-energy electrical pulses to stimulate the heart to beat at a normal rate.

Automatic Implantable Cardioverter Defibrillator

Similar to a pacemaker, an automatic implantable cardioverter defibrillator (AICD) is implanted inside the chest to help control ventricular tachycardia and fibrillation. However, these devices use high-energy pulses to treat life-threatening arrhythmias, especially those that can cause sudden cardiac arrest. Click here to learn more.

Lead Extraction of Pacemakers and Automatic Implantable Cardioverter Defibrillators

Pacemakers and automatic implantable cardioverter defibrillators (AICDs) deliver electrical stimulation to heart muscle through wires called leads. Lead extraction refers to the removal of one or more leads from inside the heart, which becomes necessary when leads stop functioning properly. This can be caused by internal or external damage to the lead, large amounts of scar tissue forming at the tip of the lead or an infection at the location where the lead connects with the implantable device.