Hackensack University Medical Center Participates in International Panel of Experts Drafting New Heart Pacing Guidelines
June 27, 2023
Hackensack University Medical Center was a member of a large panel of experts from around the world who drafted new guidelines for the use of conduction system pacing to prevent or reduce heart failure in adults and children with heart rhythm abnormalities. Taya V. Glotzer, MD, an electrophysiologist and director of Cardiac Research at Hackensack University Medical Center and professor of medicine at Hackensack Meridian School of Medicine, was one of the authors. The findings were published in the journal Heart Rhythm in May 2023.
"This is the new frontier of pacing," explained Dr. Glotzer. ”These are the first and only guidelines for conduction system pacing in the United States.” The European Guidelines were also recently published in February 2023.
Traditional pacemakers were introduced in the 1950s, and consisted of a single wire (lead) placed in the right ventricle (bottom chamber of the heart) to prevent the heart from beating too slowly. The natural conduction system in the normal heart directs impulses to the right and left ventricles simultaneously. When a pacing lead is placed in only one chamber, the ventricles beat sequentially instead of simultaneously.
“Over the last 50 years, we have learned that single ventricle pacing is actually bad for the heart. It can make the heart weak," explained Dr. Glotzer. In people who need frequent pacing, this can cause what is known as "pacemaker-induced cardiomyopathy." In addition, when patients develop a bundle branch block on their EKG due to a prior heart attack, or due to aging of the conduction system, the bottom chambers of the heart beat sequentially because of the electrical delay, which can also make the heart muscle weak.
In the 1980s, biventricular pacemakers were introduced to resynchronize the beating of the left and right chambers of the heart. Biventricular pacing consists of implanting two leads — one for the right ventricle and one for the left ventricle — to pace both sides of the heart simultaneously and restore the chambers pumping in synchrony. Remarkably, this was shown in thousands of patients to improve mortality, improve the heart's pumping ability, and prevent heart failure. Biventricular pacing became the standard of care for patients with bundle branch blocks and weak heart muscles.
In the early 2000s, researchers began developing ways to pace the heart's own conduction system, which naturally activates the right and left sides simultaneously. The native conduction system begins at one point at the top of the heart and goes down specialized conduction tissue to the right and left sides. “Wouldn’t it be fantastic if we could use one lead instead of two, and use the heart’s own conduction system to re-synchronize the pumping function of the heart?” Dr. Glotzer mused.
This new and exciting technique is called conduction system pacing and involves the insertion of a single lead into the heart’s native conduction fibers. By anchoring the lead in the right side of the septum (the wall between the right and left sides of the heart) and advancing the wire to the left side of the heart, the pacemaker can stimulate the heart's natural conduction system. Technically the procedure may prove to be easier than biventricular pacing, and tools are currently only in their infancy, explained Dr. Glotzer.
Conduction system pacing is now an alternative to biventricular pacing in patients with heart failure, bundle branch blocks, weakened heart muscles, and those who require pacing at least 20%-40% of the time. One type of conduction system pacing targeting the His bundle (an important group of heart cells in the electrical system) was approved by the FDA in 2018. A second type of conduction system pacing, left bundle branch area pacing, was FDA approved in 2022.
The new conduction system pacing guidelines were released by the Heart Rhythm Society, Asia Pacific Heart Rhythm Society, and Latin American Heart Rhythm Society. The authors emphasize the importance of shared decision-making between providers and patients when considering treatment with a conduction system pacing device. They note that these discussions should account for a patient's values, preferences, and care goals while considering the potential advantages and risks associated with pacing therapy. In addition, the authors acknowledge that critical gaps remain in our current understanding in the field and highlight novel directions for future research.
Hackensack University Medical Center is doing its own study on the long term effects of conduction system pacing, led by Dr. Glotzer. The hospital is also participating in a major prospective randomized clinical trial as one of several sites in the United States and Canada comparing conduction system pacing to biventricular pacing in patients who have bundle branch blocks and weak heart muscles, with Dr. Glotzer as the site's primary investigator. The study will begin enrolling patients next year.
Concluded Dr. Glotzer, "This innovative and exciting work can only be done at an academic medical center on the forefront of advanced cardiac therapies.”