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More than 50 individuals experiencing a fainting disorder have now undergone a groundbreaking treatment to address the root cause of their ailment. (This is a stock image.) (Image credit: CRISTINA PEDRAZZINI/SCIENCE PHOTO LIBRARY via Getty Images)Share this article 0Join the conversationFollow usAdd us as a preferred source on GoogleSubscribe to our newsletter
For Sarah Hall, each meal was fraught with peril.
She has a rare condition known as cardioinhibitory syncope, which leads to overly active nerve signals prompting the heart to cease beating in response to unconscious bodily functions, such as deglutition. The act of swallowing food caused Hall’s heart to stop beating as many as 12 times daily, frequently resulting in her losing consciousness.
Hall’s condition showed no improvement with existing treatments, but a novel procedure has transformed her life, along with the lives of many others.
In research presented at the British Cardiovascular Society’s annual gathering, scientists revealed that 25 individuals with the condition experienced significant betterment following an experimental intervention. The preliminary findings, which await peer review, are encouraging but necessitate verification.
“It’s crucial to acknowledge that this remains a relatively nascent therapy, and larger investigations along with extended follow-ups are still required to foster a deeper comprehension of its longevity and to pinpoint which patients stand to gain the most,” stated Dr. Sirisha Vadali, a cardiologist at HonorHealth who was not involved in the study.
When “rest and digest” goes haywire
The autonomic nervous system governs the electrical impulses the body relies upon for involuntary, routine functions, such as consumption and repose. This encompasses the body’s reciprocal “fight-or-flight” and “rest-and-digest” mechanisms.
The latter system dispatches the majority of its signals via the vagus nerve, which originates in the brainstem and extends through the thoracic and abdominal cavities. As the body perceives changes, such as sustenance entering the pharynx or the lower limbs assuming a crouched posture, the vagus nerve furnishes the brain with updates on these events, enabling it to subtly modify digestion, respiration, and cardiac rhythm accordingly.
In certain fauna, vagal stimulation is implicated in a more pronounced physiological process: torpor. Hibernating creatures, akin to ursids, undergo a potent surge of signaling through the vagus nerve upon entering their winter slumber, which curtails their metabolic rate for extended periods.
The vagus nerve interfaces with numerous organs within the chest and abdomen.
(Image credit: Shutterstock)
Individuals afflicted with cardioinhibitory syncope experience a “hibernation response” due to excessively potent vagus nerve signals, as explained by Dr. Boon Lim, a consultant cardiologist at Imperial College Healthcare NHS Trust and lead researcher, to Live Science.
The vagus nerve transmits impulses to the ganglionated plexi, a network of nerve endings situated on the heart’s exterior. These signals subsequently reach the body’s intrinsic system responsible for maintaining heart rate. When these signals are excessively strong, they momentarily disrupt this mechanism, causing a complete cessation of the heartbeat.
Numerous factors can precipitate this heightened vagal reaction. For the 50-year-old Hall, swallowing served as the trigger, whereas for others with the condition, acute abdominal discomfort can initiate the response.
Why we faint
Syncope, the clinical designation for fainting, is a prevalent occurrence. Lim estimates that 40% of individuals experience fainting at some juncture in their lives, typically due to vagus nerve signals causing a temporary drop in blood pressure. Insufficient blood flow to the brain results in a transient loss of consciousness.
However, in cardioinhibitory syncope, the heart halts completely for several seconds as a consequence of hyperactive vagal signaling. The intensity of the vagus nerve’s impulses to the heart is largely determined by genetic predisposition. Less than 5% of individuals seeking medical attention for syncope are diagnosed with cardioinhibitory syncope.
The condition is generally not life-threatening, according to Vadali, but its unpredictability significantly disrupts daily life. “Many patients may develop anxiety regarding the timing of the next episode,” she remarked.
“I was compelled to cease driving and was medically excused from work for several months. It was one of the most challenging periods of my existence. I began experiencing distressing thoughts that my heart might simply cease beating during meals and never resume. However, I can now live without apprehension,” Sarah Hall stated in a release.
(Image credit: Courtesy of Sarah Hall)
Boon recounted the case of a patient named Rob, who reported recurrent fainting episodes. A graph illustrating the fluctuations of Rob’s pulse on a typical afternoon revealed his heartbeat’s erratic rhythm becoming still — one of several daily occurrences. “It abruptly pauses for nearly five seconds without apparent cause,” Lim commented.
For individuals with cardioinhibitory syncope, the optimal course of action previously involved the implantation of a pacemaker, according to Lim. However, this is not a definitive resolution; pacemaker batteries require replacement approximately every ten years. Patients who receive pacemakers at younger ages may face protracted health risks as the devices degrade, and battery replacement surgeries can lead to infections.
Presently, Lim and his associates have demonstrated that a procedure termed cardioneuroablation can substantially enhance the well-being of patients like Rob.
During this procedure, Lim navigated a slender wire through Rob’s body until it reached his heart, specifically targeting the ganglionated plexi on the organ’s surface. Lim then administered a radio-frequency energy pulse to the plexi, ablating the tissue and thereby diminishing the interference with the heart’s intrinsic pacemaker.
Lim’s team performed this procedure on 25 individuals at Imperial College London between 2013 and 2023. On average, these patients experienced fewer than one fainting episode in the subsequent year. The researchers reported that this translated into considerable improvements in the patients’ quality of life.
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Three patients necessitated supplementary procedures, as the ganglionated plexi can occasionally regenerate. While the procedure is moderately invasive, it may still present a more attractive alternative to patients compared to recurrent pacemaker maintenance, according to the researchers.
As of now, Lim’s team has utilized cardioneuroablation to treat 52 individuals. Vadali indicated that the initial data presented at the conference is encouraging, but further research is warranted to ascertain the long-term efficacy of its effects.
For Hall, the intervention proved life-altering. She has not experienced fainting since, even during meal times.
“I am able to drive; I am able to work,” she stated in a release. “It feels as though everything has come full-circle.”
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