Keeping pace with cardiovascular diseases research

Posted on Sep 3, 2019 in Scroll Images

SAN FRANCISCO – For many people, a quickened heart beat is a normal physiologic response to physical activity or stress. But for at least 2.7 million Americans with atrial fibrillation, an abnormal or irregular heartbeat can lead to blood clots, stroke, heart failure, and other heart-related complications if left untreated. Learn how research at Sutter is helping guide and inform care for patients with this cardiovascular disease.

Normally, the heart contracts and relaxes to a regular beat. In atrial fibrillation, the upper chambers of the heart (called the atria) beat irregularly instead of pumping effectively to move blood into the lower chambers (the ventricles). People with the condition may experience irregular heartbeat, shortness of breath, a feeling of fluttering in the chest, dizziness, and weakness. They are also at higher risk for stroke.

Treatment for atrial fibrillation focuses on two cornerstone strategies: the first is to restore normal rhythm so that people feel better; the second is to prevent stroke.

To restore normal cadence, treatment includes medications to help reset and control the heart’s rhythm. Anti-arrhythmic medications may also be prescribed to help prevent future episodes of atrial fibrillation. An alternative to medications is ablation. “Ablation is a therapy whereby electrical energy is used to eliminate the triggers that lead to atrial fibrillation,” says Christopher Woods, MD, PhD, FHRS, Director of Cardiac Electrophysiology at Mills Peninsula Medical Center, and Electrophysiology Physician at Sutter.

Christopher Woods, MD, PhD, FHRS

Christopher Woods, MD, PhD, FHRS

Dr. Woods notes that the standard approach to ablation of atrial fibrillation is ablation of the tissue connecting the left atrium to the pulmonary veins in the left atrium of the heart.

Stroke prevention hinges on the use of either anticoagulation treatment with drugs such as direct oral anticoagulants to lower the risk of clots that form as a result of atrial fibrillation, or by mechanically eliminating the areas where over 90% of clot formation occurs—the left atrial appendage in the heart—with a procedure known as “left atrial appendage exclusion”.

“At Sutter, we pursue research to explore more effective treatment options for patients with atrial fibrillation,” says Dr. Woods.


Here’s how:

Testing new procedures to treat atrial fibrillation

Clinical trials at Sutter test the effectiveness and safety of new surgical approaches and techniques for cardiac ablation—a procedure to scar or destroy tissue in the heart that allow incorrect electrical signals to cause an abnormal heart rhythm.

“Atrial fibrillation can be quite debilitating to patients,” says Dr. Woods. “It can dramatically impact their quality of life and worsen their mortality, and sometimes it has been present for so long patients do not even recognize their limitations. Ablation can be a transformational procedure for patients, and their stories are so important because they show how potentially damaging atrial fibrillation can be.”

“Atrial fibrillation does not strike like a lightning bolt or a heart attack,” says Dr. Woods. “Patients don’t notice how they have changed their lives to accommodate this condition. Ablation can be a transformational procedure for patients, and their stories are so important because they shows how potentially damaging atrial fibrillation can be.”

For patients with paroxysmal atrial fibrillation, a condition when atrial fibrillation comes and goes on its own, ablation—often done repeatedly—can be approximately 90% effective.1 However, patients with persistent atrial fibrillation, a condition when atrial fibrillation is continually present, do not fare as well because the disease has progressed more aggressively.2

“For this reason, Sutter is dedicated to advancing the care of patients with persistent atrial fibrillation through novel research,” says Dr. Woods. He is leading a randomized trial called the Investigator-Initiated Randomized Controlled Trial Comparing Two Radiofrequency Ablation Strategies in Patients with Persistent Atrial Fibrillation.

A standard ablation procedure eliminates the tissue important for atrial fibrillation around the pulmonary veins. In this randomized trial, the tissue between the pulmonary veins is also targeted because it originated from the same embryonic cells as the pulmonary veins—and thus has the potential to exacerbate atrial fibrillation.  Mills-Peninsula Medical Center is one of only two sites to offer this trial to patients.

“Our goal is to understand whether this simple addition to a standard atrial fibrillation ablation can help maintain freedom from atrial fibrillation in patients with persistent atrial fibrillation after one year,” says Dr. Woods. To date, over 50 patients at Sutter have been enrolled in the study.

In addition, Dr. Woods’ group is studying the best way to deliver energy. “Presently there is no agreed upon way to quantify when a good ablation has been done. We are working to quantify this parameter through the LSI Workflow Study. LSI is a dimensionless parameter that can be tracked from ablation to ablation to ensure common, definable targets are used from site to site.” Mills-Peninsula Medical Center is the only center offering the LSI Workflow Study in the Bay Area.

This same strategy of posterior wall ablation is also being investigating using a more invasive surgical approach. DEEP (dual epicardial and endocardial ablation procedure) is a combination procedure whereby a cardiac surgeon and an electrophysiologist work together. DEEP is known as a “hybrid” procedure because it’s more invasive than standard ablation, but less invasive then open-heart surgery.

The cardiac surgeon performs a minimally invasive surgical ablation on the outside of the heart (epicardial), and in a follow-up procedure approximately 90 days later, the electrophysiologist performs a catheter ablation on the inside of the heart (endocardial).

Junaid Khan, MD, a cardiothoracic surgeon and researcher at Sutter’s Alta Bates Summit Medical Center,
has performed over 50 of the procedures at Alta Bates Summit Medical Center.

Junaid Khan, MD

Junaid Khan, MD

“Our goal through the DEEP study is to provide patients freedom from atrial fibrillation over a 12-month follow-up period without patients being on rhythm control (antiarrhythmic) drugs,” says Dr. Khan.

Alta Bates Summit Medical Center is one of only two sites across Northern California to offer DEEP.

“By offering DEEP and the investigator-initiated study at Sutter, we hope to help identify the best approach to treating persistent atrial fibrillation,” says Dr. Khan. “The hypothesis is that a combination of endocardial, catheter- based, and minimally invasive surgery with exclusion of the left atrial appendage—the most common site of clot formation in these patients—is the best approach and minimizes risk.”


Stroke prevention for atrial fibrillation is also critical to manage in patients with atrial fibrillation.3 “The standard approach to stroke prevention regardless of ablation is the use of anticoagulation to reduce this risk,” says Dr. Woods.

He notes that some patients successfully treated with ablation stay on anticoagulant medications to reduce their risk of stroke. Generally, patients at low risk of stroke don’t require the medications. And patients at higher risk of stroke are usually advised to stay on anticoagulants. “Small studies—including those conducted by Roger Winkle, MD, in our group—have suggested it may be possible to stop anticoagulation after successful ablation. But robust studies are lacking.”

“Randomized trials are underway worldwide to understand the nuances of stroke risk in patients with atrial fibrillation, and to determine whether ablation alone can eliminate the risk of stroke or whether devices can eliminate the need for anticoagulation,” says Dr. Woods.

One such trial Dr. Woods leads at Sutter is the OCEAN (Optimal Anticoagulation for Higher Risk Patients Post-Catheter Ablation) study. The prospective, open-label, randomized trial is testing the efficacy and safety of the newest Watchman™ device—a small implant placed in the heart that can reduce the risk of stroke in patients with atrial fibrillation—versus anticoagulation in patients already treated with cardiac ablation.

“OCEAN was designed to compare medical approaches for stroke prevention in people who have atrial fibrillation and moderate stroke risk, and who have undergone ablation to eliminate or substantially reduce the arrhythmia,” says Dr. Woods. He notes that atrial fibrillation is normally associated with an increased risk of stroke, which can be prevented in many patients with appropriate blood thinner therapy. OCEAN will compare treatment with oral anticoagulant therapy after successful ablation, to therapy with one daily Aspirin®.

The goal of the OCEAN study is to enroll 1,500 patients worldwide. The trial will begin this fall. Mills-Peninsula Medical Center is the only Sutter Health Bay Area site included in this trial.

A history of atrial fibrillation research at Sutter

Atrial fibrillation research and innovation at Sutter stem from a legacy of pioneering work across the system. Renowned expertise in surgical ablation procedures for the condition started with the work of James Longoria, MD, a cardiovascular surgeon at the Sutter Heart and Vascular Institute at Sutter Medical Center, Sacramento.

Dr. Longoria brought many new surgical techniques to the Valley Area, including a minimally invasive approach to surgical ablation for the treatment of atrial fibrillation, known as the Totally Thorascopic Maze (TT Maze) Procedure.

TT Maze is often recommended for patients whose atrial fibrillation is not controlled by other treatments such as cardiac catheter ablation—a procedure to scar or destroy tissue in the heart that’s allowing incorrect electrical signals to generate abnormal heart rhythm.

TT Maze involves smaller incisions and less scarring, less postoperative pain, and typically a faster return to normal living than traditional open heart Cox Maze III surgery used to correct atrial fibrillation.

Nationally renowned for performing this technique, Dr. Longoria is sought after to lecture and train other surgeons in using this exciting approach.

“As we continue to refine the procedure through new research, patients’ recovery times have shortened,” says Dr. Longoria. “Many patients say that comparing life before the surgery to after is like comparing night to day.”

TT Maze involves small incisions in the patient’s chest, and the use of special instruments to create scars on the heart to block and redirect the abnormal electrical impulses causing the atrial fibrillation. In many cases, people treated with TT Maze return home a few days after the surgery, resuming normal routine and an active lifestyle.

More Atrial Fibrillation Research at Sutter:

  • Sutter Bay Area Hospitals are participating in the national NCDR Atrial Fibrillation Registry, which compiles and shares atrial fibrillation data with participating centers. This registry will allow transparency in atrial fibrillation outcomes among all participating centers.
  • Steven Hao, MD, FACC, FHRS, Eugene and Lena H. Shao Chair in Cardiovascular Medicine at Sutter, oversees policy work, data safety committees, and national adjudication of new atrial fibrillation studies. Learn more from Dr. Hao on atrial fibrillation and other heart rhythm disorders.
  • Find more information on Sutter’s cardiovascular diseases research and clinical trials.


  1. Taghji, P. et al.  Evaluation of a Strategy Aiming to Enclose the Pulmonary Veins With Contiguous and Optimized Radiofrequency Lesions in Paroxysmal Atrial Fibrillation: A Pilot Study. JACC Clin Electrophysiol. 2018 Jan;4(1):99-108. doi: 10.1016/j.jacep.2017.06.023. Epub 2017 Sep 27.
  2. Yubing W., et al. Long-term outcome of radiofrequency catheter ablation for persistent atrial fibrillation. Medicine (Baltimore). 2018 Jul;97(29):e11520.
  3. American Heart Association (

Posted by on Sep 3, 2019 in Scroll Images | Comments Off on Keeping pace with cardiovascular diseases research