New research brings the personalized treatment of cardiac arrhythmias with an ear clip closer

For the first time, researchers have demonstrated that a special ear clip has an impact on cardiac arrhythmias. A team of scientists from the Medical Delta Cardiac Arrhythmia Lab program measured significant changes during ten open-heart surgeries. Their findings have been published this month, potentially opening the door for broader clinical application.

At least 373,700 people in the Netherlands are known to have atrial fibrillation (AF), also known as atrium fibrillation. For many people with long-standing AF, effective treatment is not possible. Medication can sometimes suppress AF, and in some cases, procedures such as ablation can help, but atrial fibrillation often recurs. Even after a "reset" through an electric shock in the hospital, the effect is often temporary.

Previous experiments and studies have suggested that a special ear clip could provide relief. By delivering electrical signals through a clip attached to the ear, cardiac arrhythmias can be treated through vagus nerve stimulation. Vagus stimulation weakens the hyperactive state of the autonomic nervous system. However, this treatment does not work for every AF patient, and the effects of vagus stimulation on the electrical conduction of the heart are unknown. Understanding how this treatment works and which patients it is effective for requires knowledge of vagus stimulation and the electrical functioning of the heart.

Researchers from the Medical Delta Cardiac Arrhythmia Lab, which brings together scientists from institutions such as Erasmus MC, TU Delft, and Amsterdam UMC, have now been able to ‘capture’ the influence of these ear clips for the first time.

Research during open-heart surgeries

Fundamental research on cardiac arrhythmias is challenging to conduct. Therefore, engineers from TU Delft have developed special equipment that allows researchers from Erasmus MC to take measurements of the heart during open-heart surgeries. During ten open-heart surgeries at Erasmus MC, they were able to measure the effects of stimulation using ear clips. Comparisons of heart rhythms with and without stimulation were then made using analysis methods from TU Delft.

The researchers observed visible effects on various properties of electrical conduction when the vagus nerve was stimulated. Some patients experienced favorable effects, while others experienced unfavorable effects on electrical conduction. These contradictory results may explain why the treatment does not work for everyone.

The research provides direct insight into the effects of vagus stimulation on the different properties of electrical conduction in the heart's atria for the first time.

Starting points for clinical application

"Ear clips that deliver electrical signals can calm the nervous system. The research shows that this affects cardiac arrhythmias in diverse ways," says prof. dr. Natasja de Groot, Medical Delta professor (Erasmus MC, TU Delft) and one of the researchers and scientific leaders of the Medical Delta Cardiac Arrhythmia Lab. "This is an important starting point because it confirms what has been suspected for a while. The scientific evidence we provide here opens the door to further research for the development and eventual implementation of personalized treatments for AF cardiac arrhythmia."

Read the full publication in JACC: Clinical Electrophysiology here

This study was carried out by the research groups of Prof. Dr. Natasja de Groot, Dr. Yannick Taverne, Dr. Robert van den Berg (Erasmus MC) and Prof. Dr. Ir. Wouter Serdijn (Rui Guan, TU Delft, Medical Delta PhD -candidate)