VENTRICULAR FIBRILLATION, MAPPING AND MODELING

Project: Research project

Description

DESCRIPTION The applicant's
overall objective would be to elucidate the mechanisms of ventricular
fibrillation (VF) using a combination of high resolution (500-electrode)
mapping and computer simulations. The focus would be on global rather
than cellular mechanisms. Hypotheses to be tested are: 1. Reentrant
rotors are present during Wigger's stage II VF and are responsible for
maintaining VF. 2. The generation and maintenance of rotors depend on
myocardial fiber orientation and the influence of the Purkinje fiber
network. 3. A critical mass is needed to sustain VF because of the
limited life span of the reentrant rotors. The role of the Purkinje
network would be evaluated by performing experiments with and without
the Purkinje network ablated using Lugol's solution. Fiber orientation
would be determined by histopathological examination. The computer
simulation studies would be based on a three-dimensional model of
myocardial activation using the (modified) FitzHugh-Nagumo system of
equations. An existing, detailed finite-element model of the
architecture of the canine heart would be used to represent the geometry
and structure (i.e. fiber orientation). Model parameters would be
obtained by fitting simulated activation patterns in two-dimensional and
three-dimensional models to measured normal and reentrant patterns
mapped in small regions of the canine heart. The model would be
extrapolated to simulate global activation in the whole heart and used
to study the effect of heart size on VF and to examine the "critical
mass" hypothesis in relation to the number of rotors. The model would
also be used to study the role of fiber orientation and of the Purkinje
network on rotor formation and maintenance.
StatusFinished
Effective start/end date9/1/928/31/97

Funding

  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health

Fingerprint

modeling
computer simulation
electrode
fibre
experiment
parameter
effect

ASJC

  • Medicine(all)