A new catheter design using needle electrode for subendocardial RF ablation of ventricular muscles: finite element analysis and in vitro experiments.
Radio-frequency (RF) cardiac ablation has been very successful for treating arrhythmias related with atrioventricular junction and accessory pathways with successful cure rates of more than 90%. Even though ventricular tachycardia (VT) is a more serious problem, it is known to be rather difficult to cure VT using RF ablation. In order to apply RF ablation to VT, we usually need to create a deeper and wider lesion. Conventional RF ablation electrodes often fail to produce such a lesion. We propose a catheter-electrode design including one or more needle electrodes with a diameter of 0.5-1.0 mm and length of 2.0-10 mm to create a lesion large enough to treat VT. One temperature sensor could be placed at the middle of the needle electrode for temperature-controlled RF ablation. From finite element analyses and in vitro experiments, we found that the depth of a lesion is 1-2 mm deeper than the insertion depth of the needle and the width increases as we increase the diameter of the needle and the time duration. We showed that a single needle electrode can produce a lesion with about 10-mm width and any required depth. If a wider lesion is required, more than one needle with suggested structures can be used. Or, repeated RF ablations around a certain area using one needle could produce a cluster of lesions. In some cases, a catheter with both conventional electrode and needle electrode at its tip may be beneficial to take advantage of both types of electrode.
Woo
E J
EJ
School of Electronics and Information, Kyung Hee University, Yongin, Kyongki-do, Korea.
Tungjitkusolmun
S
S
Cao
H
H
Tsai
J Z
JZ
Webster
J G
JG
Vorperian
V R
VR
Will
J A
JA
D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation*; D002417:Cattle; D004566:Electrodes; D004867:Equipment Design; D006352:Heart Ventricles / Q000601:surgery*; D066298:In Vitro Techniques; D008955:Models, Cardiovascular