Key Points
- To quantify how defibrillation paddle placement and paddle diameter affect the distribution and uniformity of electrical current in the myocardium.
- Constructed a 3D finite element model from 21 cross-sectional thoracic CT scans of a 14.5 kg beagle, spaced at 0.82 cm intervals.
- Assigned electrical conductivity values to eight distinct tissue types, incorporating anisotropic conductivity for skeletal muscle.
- Simulated and quantitatively compared myocardial current density distributions across six paddle configurations and two paddle sizes (8 cm and 12 cm).
- Placing one or both paddles closer to the heart delivered a higher fraction of total current to the myocardium but induced a less uniform current distribution.
- Proximal paddle placements produced localized myocardial current densities approaching the known threshold for myocardial damage during successful shocks.
- Paddles measuring 12 cm in diameter provided modest distribution advantages over 8 cm paddles, reducing extreme localized current densities.
Structured PICO
Does paddle placement and size affect defibrillation current distribution in a canine thorax model?
PPopulationThree-dimensional finite element model of the conductive anatomy of a canine thorax, constructed from CT scans of a 14.5 kg beagle
IInterventionSix paddle pairings and two paddle sizes (8 cm and 12 cm) for transthoracic electrical defibrillation
CComparatorComparison between different paddle placements and sizes (8 cm vs 12 cm)
OOutcomeCurrent density distributions (fraction of current to the heart and uniformity of myocardial current density)surrogate
Computational modeling suggests that 12 cm defibrillation paddles may offer modest advantages over 8 cm paddles, and paddle placement significantly affects myocardial current distribution and potential for damage.