Vortices Termination in the Cardiac Muscle
Methods for termination of three-dimensional electrical vortices in the heart are needed for development of patient-friendly cardiac defibrillation techniques (Nature 475, 235, 2011). The defibrillation technique used today is the delivery of a high-energy electric shock (360 J, 1 kV, 30 A, 12 ms, when applied externally) often associated with severe side effects. Developing low-energy defibrillation methods are hampered by two problems: the unknown locations of the cores of the vortices, and the unpredictable phases of the vortex waves rotating around these cores. The first problem has been resolved through the use of electric field pulses to excite the cores of all pinned vortices simultaneously. Approaches to solve the second problem are being developed. One of them is based on the phase scanning of all pinned vortices in parallel to hit the critical time window (“Vulnerable Window”, VW) of every pinned vortex. We investigate the related physical mechanisms and describe problems created by scanning. We describe also a mechanism by which a 3-dim scroll vortex may be terminated with a VW of the full 2π radians. It makes knowledge of the wave phase no longer required. We describe a mechanism terminating also a free (not pinned) vortex, when the vortex’s core passes not very far from a defect. About 500 experiments with termination of vortices during ventricular fibrillation in pig isolated hearts confirm that pinned vortices, hidden from direct observation, are significant in fibrillation. These results form a physical basis needed for creation of new effective methods for termination vortices underlying fibrillation.
KeywordsCardiac defibrilation Vortex waves Pinning
The research leading to the results has received funding from Max Planck Gesellschaft, the European Community Seventh Framework Programme FP7/2007–2013 under Grant Agreement 17 No. HEALTH-F2-2009-241526, EUTrigTreat, and from EPSRC (UK) grant EP/I029664. We acknowledge support from the German Federal Ministry of Education and Research (BMBF) (project FKZ 031A147, GO-Bio), the German Research Foundation (DFG) (Collaborative Research Centres SFB 1002 Project C3 and SFB 937 Project A18), the German Center for Cardiovascular Research (DZHK e.V.), and EPSRC (UK) grant EP/N014391. US NIH grant no. R01HL089271.
Ethics The study was reviewed and approved by the ethics committee, permit no. 33.9-42052-04-11/0384, Lower Saxony State Office for Customer Protection and Food Safety.
Competing Interests We have no competing interests.
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