The origin of Diastolic Micro-Signals observed in defibrillator recipients might be qualitatively explained by a simple computational model

In previous studies investigating intracardiac electrograms (Egm) obtained from implantable cardioverter defibrillators (ICD), the presence of Diastolic Micro-Signals (DMS) preceding the initiation of ventricular tachyarrhythmias (VT) has been observed both in coronary artery disease (CAD) and in dilated cardiomyopathy (DCM). We propose a mechanism, based on a recently published computational model, to qualitatively explain the DMS for the case of ischemic cardiomyopathy. The model based on a bi-dimensional network of Beeler-Reuter cardiac cell, is able to reproduce all the erratic arrhythmias under the assumptions that the gap-junction conductance are non-linear and fluctuating, and there is a scar in the tissue. Under such hypotheses, an electrical activity may propagate within the scar and, occasionally, it may propagate outside the scar and initiate a premature cardiac beat. Our hypothesis is that, in ICD recipients with ischemic cardiomyopathy, the DMS reveal the presence of a propagating wavefront within the scar, monitored by the intracardiac electrocatheter which is assumed to be placed in the proximity of the scar lesion.