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What Is an Electrophysiologist?

Contributor: Michael Mazzini, MD
Electrophysiologist checks patient’s heartbeat

Electrophysiologists are a growing specialty in heart health. Also called cardiac electrophysiologists, they’re experts on your heart’s electrical system, which controls your heartbeat.

Electrophysiologists run tests to understand why your heart has an irregular rhythm. They also perform procedures or implant devices that help correct your heart’s rhythm. You may see an electrophysiologist in a clinic or hospital.

“I fell in love with electrophysiology as soon as I learned about it when I was in my residency,” says Michael Mazzini, MD, a Mass General Brigham electrophysiologist who cares for patients at Wentworth-Douglass Hospital and Massachusetts General Hospital. “It’s a challenging field, but it’s also immensely satisfying to give people relief that can last a lifetime.”

What is the difference between a cardiologist and an electrophysiologist?

An electrophysiologist is a cardiologist who has completed an additional 1 to 2 years of specialized training. “Electrophysiology is a subspecialty of cardiology,” says Dr. Mazzini.

You’ll probably need a referral from your primary care provider (PCP) or cardiologist to see an electrophysiologist. If a hospital or ER visit reveals a heart rhythm problem, you’ll get a referral from the hospital.

Electrophysiologists treat all types of arrhythmias, or abnormal heart rhythms.

Michael Mazzini, MD
Cardiac Electrophysiologist
Mass General Brigham

What conditions does an electrophysiologist treat?

“Electrophysiologists treat all types of arrhythmias, or abnormal heart rhythms,” says Dr. Mazzini. Heart rhythm problems become more common as people age. They can also be complications of other conditions, such as heart valve diseases and untreated sleep apnea.

Examples of arrhythmias include:

  • Atrial fibrillation: Also known as AFib, the upper part of your heart creates a rhythm that’s too fast.
  • Bradycardia: Your heart beats too slowly.
  • Ventricular fibrillation: The lower areas of your heart don’t pump blood normally.
  • Supraventricular tachycardia: Your heart beats too fast.

“I also treat people who have unexplained fainting and rare genetic conditions that affect heart rhythm,” says Dr. Mazzini.

What to expect at an electrophysiologist appointment

“When we first meet, I spend a lot of time reviewing your medical history,” says Dr. Mazzini. “I listen to your concerns and symptoms.”

Depending on your symptoms, you may need tests to identify the type and cause of your heart rhythm problem. Some tests, such as an electrocardiogram (EKG), give readouts of your heart’s rhythm. You may need to wear a monitor that records the signals from your heart over several days. Imaging tests, such as CT and MRI scans, show images of your heart’s structure and may help reveal problems.

You also may need an electrophysiology test, which involves putting a thin tube (or catheter) into a vein and threading very fine wires into your heart. These wires, called electrodes, measure the electrical signals in different parts of your heart. This allows your electrophysiologist to see exactly which part of your heart may be causing the abnormal rhythm.

“Once we understand what’s going on with your heart rhythm, we’ll talk about a treatment plan,” says Dr. Mazzini. “I’ll explain your options, possible risks, benefits, and reasons for the treatment. I’ll also help you understand what to expect and what you’ll experience during and after your treatment.”

Procedures and implants for heart rhythm problems

Electrophysiologists use unique procedures and devices to help people with heart rhythm problems. One of those procedures is ablation, which involves destroying cells in the specific areas of the heart that cause arrhythmias. Ablation creates a scar that blocks the electrical signals from creating abnormal heart rhythms.

Different types of ablation use different methods to create the scars. They include:

  • Cryoablation, which freezes the cells.
  • Radiofrequency ablation, which heats and destroys the cells.
  • Pulse field ablation, a newer technique that uses very precise electrical pulses to destroy the cells.

During a catheter ablation, your electrophysiologist threads a catheter through a blood vessel to reach your heart. The procedure is minimally invasive, and you may not need an overnight hospital stay afterward.

Some arrhythmias are best corrected with implanted devices. Electrophysiologists perform these procedures, too. The devices include:

  • Implantable cardioverter defibrillators (ICD), which find and correct abnormal heart rhythms. This device uses small wires that go through your veins into your heart. When the ICD detects an arrhythmia, it sends small electrical pulses into your heart to bring the rhythm back to normal.
  • Left atrial appendage occlusion devices (LAAOD), which help people with certain types of arrhythmia reduce their risk of stroke. These devices close off a small area of your heart called the left atrial appendage. This closure prevents clots that may form in this area from entering your bloodstream and causing a stroke.
  • Pacemakers, which use electrical pulses to keep your heart beating at a normal rhythm.
  • Subcutaneous implantable cardioverter defibrillators (S-ICD), which are similar to ICDs but do not have wires that run into your heart. They work the same way as an ICD but deliver an electrical pulse through a single wire placed near your heart.

Learn about Mass General Brigham Heart services

Headshot of Michael Mazzini, MD


Cardiac electrophysiologist