Rotors and the Dynamics of Cardiac Fibrillation

Abstract

The objective of this article is to present a broad review on the role of cardiac electrical rotors and their accompanying spiral waves in the mechanism of cardiac fibrillation. At the outset, we present a brief historical overview regarding reentry, and then discuss the basic concepts and terminologies pertaining to rotors and their initiation. Thereafter, the intrinsic properties of rotors and spiral waves, including phase singularities, wavefront curvature and dominant frequency maps are discussed. The implications of rotor dynamics for the spatio-temporal organization of fibrillation, independent of the species being studied are touched upon next. The knowledge gained regarding the role of cardiac structure in the initiation and/or maintenance of rotors and the ionic bases of spiral waves in the last two decades, and its significance for drug therapy is reviewed subsequently. We conclude by looking at recent evidence suggesting that rotors are critical in sustaining both atrial and ventricular fibrillation (AF, VF) in the human heart, and its implications for treatment with radio-frequency ablation.

EHRA/HRS/APHRS/SOLAECE expert consensus on atrial cardiomyopathies: definition, characterization, and clinical implication

“…234,235 On the other side are those who adhere to the theory that fibrillation is a consequence of the continued activity of a few vortices (rotors) that spin at high frequencies, generating 'fibrillatory conduction'. 236,237 In either case, arrhythmia maintenance is favoured by abbreviated APD/refractory period. 13,238,239 Another prerequisite of the multiple wavelet hypothesis is that there should be slow conduction, which is not the case for rotors.…”

Mechanisms of Atrial Fibrillation – Reentry, Rotors and Reality

“…A rotor, however, is able to move through space and, due to constant source-sink current mismatch at the PS and core, under certain circumstances the rotor can meander in various complex forms which in turn have important effects on rotor behaviour and sustainability. 6,22 The variable curvature of a rotor establishes a gradient of conduction velocity, and because the core constantly acts as a current sink from cells in close proximity to the core, this in turn also establishes gradients of action potential duration (APD) and wavelength which rise with increasing distance from the PS. 6,22 As a result of these gradients, rotors establish a gradient of excitable gap and heterogeneous conduction properties that also follow the spiral shape of the rotor and influence its behaviour.…”

Control of electrical turbulence by periodic excitation of cardiac tissue

“…abnormal or irregular heart rhythms) including atrial fibrillation (AF), ventricular fibrillation (VF), and ventricular tachycardia (VT). The nonlinear dynamics of electrical excitation waves in cardiac tissue has been studied extensively in experiment and simulation for more than two decades, for recent reviews see e. g. [1][2][3][4][5] . VF represents a particularly dangerous malfunction of the heart, in which synchronous excitation and contraction of different parts of the ventricles is lost, potentially causing sudden death if left untreated for more than a few minutes.…”