Nav: Home

Therapy for abnormal heartbeats may cause brain injury

January 24, 2017

A common treatment for irregular heartbeats known as catheter ablation may result in the formation of brain lesions when it is performed on the left side of the heart, according to new research at UC San Francisco. Importantly, there also is evidence these lesions may be associated with cognitive decline, meaning they may not be benign.

In a small study of patients undergoing catheter ablation for common abnormal heartbeats from the lower chamber of the heart (premature ventricular contractions (PVCs)), researchers found a significantly higher rate of seemingly asymptomatic brain injury due to embolism among the patients whose therapy occurred on the left ventricle of the heart, which supplies blood to the brain, compared to patients whose therapy was conducted on the right ventricle, which pumps blood to the lungs.

The researchers recommend further study on the impact of these lesions and strategies to avoid them. Their study appears online Jan. 24, 2017, in the American Heart Association journal Circulation.

"The rate of asymptomatic emboli in similar procedures for other types of heart rhythm disturbances tends to be 10-20 percent," said study senior author Gregory Marcus, MD, MAS, a UCSF Health cardiologist and director of clinical research in the UCSF Division of Cardiology.

"Our study finding is relevant to a large number of patients undergoing this procedure and hopefully will inspire many studies to understand the meaning of and how to mitigate these lesions," Marcus said. "This also will become an important consideration as we think about how to optimally help the large number of people out there with PVCs."

PVCs are extra, abnormal heartbeats originating in the ventricles. They disrupt the heart's regular rhythm and typically have not been a reason for concern.

However, recent research by Marcus and his colleagues demonstrated that PVCs are an important predictor of heart failure and mortality and can cause very bothersome symptoms. Further, such early beats occurring continuously for more than 30 seconds is a potentially serious cardiac condition called ventricular tachycardia (VT).

Given growing recognition of all these phenomena, catheter ablation for PVCs and VT is mainstream and becoming even more common, with well more than 235,000 such procedures performed annually. It is also increasingly used for patients with heart failure due to weak heart muscle that may improve after frequent PVCs are eradicated.

In this minimally invasive procedure, thin, flexible wires called catheters are inserted into a vein and threaded into the heart. The tip of the catheter either delivers heat or extreme cold to destroy tissue responsible for starting or maintaining the abnormal heart rhythm. The procedure can result in the complete and permanent cessation of the PVCs/VT that are targeted and is generally considered low risk.

An "embolism" occurs when an object moves through the bloodstream from one part of the body to another. Catheters placed in the left side of the heart may lead to brain injury if something that can occlude a blood vessel is either formed, such as a blood clot, or dislodged by the catheter and travels to the brain. Because the right side of the heart leads to the lungs, not the brain, brain emboli generally are not a concern.

Data from previous left heart-based procedures has shown that brain injury thought to be due to embolism rarely occurs. Those emboli generally have been attributed to either issues with the particular patient populations studied or the risks inherent to treating another common heart rhythm disturbance, atrial fibrillation, with ablation.

In this Circulation study, Marcus and his colleagues enrolled 18 patients scheduled for VT or PVC ablation over a nine-month period. The average patient age was 58, with half being men, half having a history of hypertension, and a majority having no known vascular disease or heart failure. Most patients were generally healthy.

Left ventricular (LV) ablation was performed in 12 patients compared to a control group of six patients who underwent right ventricular (RV) ablation. Pre- and post-procedural brain magnetic resonance imaging (MRI) was performed on each patient within a week of the ablation, along with a complete neurological examination.

Overall, seven of the 12 patients (58 percent) who underwent LV ablation experienced 16 brain embolisms combined, compared to zero patients who underwent the RV ablation. Seven of 11 patients (63 percent) who underwent a retrograde approach to their LV ablation developed at least one new brain lesion.

"Further research is important to understanding the long-term consequences of these lesions and determining optimal strategies to avoid them," said lead author Isaac Whitman, MD, UCSF cardiac electrophysiology fellow.
-end-
Other UCSF contributors to the Circulation study were Rachel Gladstone, cardiology research assistant; Nitish Badhwar, MD, professor of medicine; Henry Hsia, MD, professor of medicine; Byron Lee, MD, professor of medicine; S. Andrew Josephson, MD, Carmen Castro Franceschi and Gladyne K. Mitchell Neurohospitalist Distinguished Professor of Neurology; Karl Meisel, MD, assistant professor of neurology; William Dillon Jr., MD, Elizabeth A. Guillaumin Professor of Radiology; Christopher Hess, MD, PhD, professor of radiology; and Edward Gerstenfeld, MD, professor of medicine and holder of the Melvin M. Scheinman Endowed Chair in Cardiology. Financial support was provided by the Joseph Drown Foundation.

UC San Francisco (UCSF) is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. It includes top-ranked graduate schools of dentistry, medicine, nursing and pharmacy; a graduate division with nationally renowned programs in basic, biomedical, translational and population sciences; and a preeminent biomedical research enterprise. It also includes UCSF Health, which comprises top-ranked hospitals, UCSF Medical Center and UCSF Benioff Children's Hospitals in San Francisco and Oakland - and other partner and affiliated hospitals and healthcare providers throughout the Bay Area.

University of California - San Francisco

Related Heart Failure Articles:

New hope for treating heart failure
Heart failure patients who are getting by on existing drug therapies can look forward to a far more effective medicine in the next five years or so, thanks to University of Alberta researchers.
Activated T-cells drive post-heart attack heart failure
Chronic inflammation after a heart attack can promote heart failure and death.
ICU care for COPD, heart failure and heart attack may not be better
Does a stay in the intensive care unit give patients a better chance of surviving a chronic obstructive pulmonary disease (COPD) or heart failure flare-up or even a heart attack, compared with care in another type of hospital unit?
Tissue engineering advance reduces heart failure in model of heart attack
Researchers have grown heart tissue by seeding a mix of human cells onto a 1-micron-resolution scaffold made with a 3-D printer.
Smoking may lead to heart failure by thickening the heart wall
Smokers without obvious signs of heart disease were more likely than nonsmokers and former smokers to have thickened heart walls and reduced heart pumping ability.
After the heart attack: Injectable gels could prevent future heart failure (video)
During a heart attack, clots or narrowed arteries block blood flow, harming or killing cells in the heart.
Heart failure after first heart attack may increase cancer risk
People who develop heart failure after their first heart attack have a greater risk of developing cancer when compared to first-time heart attack survivors without heart failure, according to a study today in the Journal of the American College of Cardiology.
Scientists use 'virtual heart' to model heart failure
A team of researchers have created a detailed computational model of the electrophysiology of congestive heart failure, a leading cause of death.
Increase in biomarker linked with increased risk of heart disease, heart failure, death
In a study published online by JAMA Cardiology, Elizabeth Selvin, Ph.D., M.P.H., of the Johns Hopkins Bloomberg School of Public Health, Baltimore, and colleagues examined the association of six-year change in high-sensitivity cardiac troponin T with incident coronary heart disease, heart failure and all-cause mortality.
1 in 4 patients develop heart failure within 4 years of first heart attack
One in four patients develop heart failure within four years of a first heart attack, according to a study in nearly 25,000 patients presented today at Heart Failure 2016 and the 3rd World Congress on Acute Heart Failure by Dr.

Related Heart Failure Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...