New Low-Energy Defibrillation Method Controls Cardiac Arrhythmias

In a healthy heart, electrical impulses spread across the heart muscle in an orderly way, controlling the heart’s contractions: the ventricles and atria contract and relax at regular intervals. However, in the case of cardiac arrhythmia, these electrical pulses may spread chaotically, disrupting the regular heartbeat and impairing proper blood circulation. Atrial fibrillation is the most prevalent type of cardiac arrhythmia, affecting over 10 million individuals in Europe and the US. For those with chronic atrial fibrillation, a common remedy is defibrillation, which involves a strong electric pulse that, although effective, can be painful and potentially harmful to surrounding tissues. Now, researchers have introduced a new low-energy defibrillation method that could stop life-threatening heart fibrillations more gently.

The new technique called LEAP (Low-Energy Anti-fibrillation Pacing) has been developed by an international team of scientists led by the Max-Planck-Institute (MPI, Munich, Germany) and reduces the energy needed for defibrillation by over 80% compared to traditional methods, offering the potential for the pain-free treatment of severe cardiac fibrillation. This method involves delivering a sequence of five mild electrical signals through a cardiac catheter, allowing the heart to resume its normal rhythm within seconds. Unlike conventional defibrillators that excite all cells at once with a strong electric field, LEAP works by briefly halting the ability of heart tissue to transmit electrical signals, effectively resetting the heart's activity.

Image: Spatial-temporal excitation pattern during cardiac fibrillation on the surface of heart (field of view 6 x 6 cm2). Color code: black = resting, yellow = excited (Photo courtesy of MPI for Dynamics and Self-Organization)

This innovative approach is similar to rebooting a malfunctioning computer. However, instead of a single reset, LEAP uses low-energy pulses to synchronize the tissue to gradually stop the turbulent electrical activity in the heart which later resumes normal beating. Research involving experiments and simulations has shown that natural heterogeneities within the heart, such as blood vessels and areas of fatty or fibrotic tissue, can act as the origins for synchronizing waves. The findings suggest that LEAP could also be adapted for treating ventricular fibrillation, a more severe arrhythmic event typically managed only with external or implantable defibrillators. For the many patients who rely on implantable cardioverter-defibrillators (ICD), LEAP could potentially enhance treatment efficacy, extend battery life, reduce painful experiences, and decrease the frequency of surgical interventions to replace devices.

"The development of LEAP is a groundbreaking result and an outstanding example of successful interdisciplinary collaboration between physicists and physician-scientists, with immediate impact on the development of novel therapies for life-threatening cardiac arrhythmias," said Markus Zabel from the University Center Göttingen.

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