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Importance of Electrode Conductive Surface Area and Edge Effects on Ventricular Defibrillation Efficacy
Author(s) -
TOMASSONI GERY,
Ph.D. RAJESH PENDEKANTI,
DIXONTULLOCH ELLEN,
MINER BILL,
FAIN ERIC S.,
HOFEMANN DREW A.,
WOLF PATRICK D.
Publication year - 1997
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.1997.tb01015.x
Subject(s) - defibrillation threshold , defibrillation , electrode , superior vena cava , medicine , current density , significant difference , materials science , cardiology , chemistry , physics , quantum mechanics
Surface Area, Edge Effects, and Ventricular Defibrillation. Introduction: The role of edge effects and electrode surface area of the right ventricular (RV) trausveuous lead (TVL) on defibrillation efficacy is unknown. Methods and Results: Defibrillation threshold (DFT) testing was conducted randomly in 12 dogs using ring electrode leads in an RV/SVC (superior vena cava) or RV/SVC/patch system. The leads (RV‐4, RV‐8t, RV‐8, RV‐15) had electrode surface areas of 20%, 20%, 40%, and 70%, respectively. A computer model predicted the magnitude of electrode surface current (RV‐8t > RV‐4 > RV‐8 > RV‐15) and the potential distribution (PD) at four sites: electrode surface (site a ) and at 2 mm ( b ), 4 mm ( c ), and 8 mm ( d ) away from the surface. Despite different near‐field PDs (sites a, b, c ), PDs were nearly identical at site d. Resistance decreased as the surface area increased. DFT energy for the RV‐15 lead was lower than the RV‐4 and RV‐8t. There was no difference between energy requirements for the RV‐15 and RV‐8 leads. No difference was found in DFT current for each lead. Comparison of the RV‐8t and RV‐4 leads showed no difference in DFT energy despite a lower resistance and a greater number of edges. Conclusions: Increasing the RV TVL surface area lowered the resistance. However, surface area coverages ≥ 40% did not lower DFT energy. No significant change in DFT current occurred despite different predicted near‐Held current densities. PDs were nearly identical 8 mm from the electrode surface. Thus, the far‐field current density appears to play a more important role in determining defibrillation success.