Filament tension and phase-locked drift of meandering scroll waves
  Rotating scroll waves are self-organising patterns which are found in many oscillating or excitable systems. Here we show that quasi-periodic (meandering) scroll waves, which include the rotors that organise cardiac arrhythmias, exhibit filament tension when averaged over the meander cycle. With strong filament curvature or medium thickness gradients, however, scroll wave dynamics are governed by phase-locked drift instead of filament tension. Our results are validated in computational models of cycloidal meander and a cardiac tissue model with linear core. 
Hans Dierckx, Irina V. Biktasheva, Henri Verschelde, Alexander V.   Panfilov and Vadim N. Biktashev
nlin.PS