Identification of reentry circuit sites during catheter mapping and radiofrequency ablation of ventricular tachycardia late after myocardial infarction.

Abstract

Background. Ventricular tachycardia reentry circuits in chronic infarct scars can contain slow conduction zones, which are difficult to distinguish from bystander areas adjacent to the circuit during catheter mapping. This study developed criteria for identifying reentry circuit sites using computer simulations. These criteria then were tested during catheter mapping in humans to predict sites at which

Electrically Unexcitable Scar Mapping Based on Pacing Threshold for Identification of the Reentry Circuit Isthmus

“…For stable VTs, reentry circuit isthmuses were defined from entrainment mapping as sites where pacing entrained VT with concealed fusion, a postpacing interval equal to the VT cycle length, and stimulus-QRS interval Ͻ70% of the VT cycle length. 8 For unstable VTs, reentry circuit isthmuses were defined on the basis of the results of pace mapping as sites where the QRS morphology matched that of VT with a stimulus-QRS Ͼ40 ms. Although confirmation that the site was in the reentry circuit was not directly obtained, these findings have been shown to be related to the reentry circuit exit and sites where ablation abolishes inducible VT. 9,10 Catheter Ablation A series of ablation lesions were made to transect isthmuses.…”

Cardiac Radiosurgery for Malignant Ventricular Tachycardia

“…Catheter ablation is often used as primary therapy with success rate in the range of 53 -67% [3]. There are a big variety of reentrant circuits, involving subepicardial, subendocardial, and intramural reentry pathways [4], so radiofrequency (RF) ablation is not always successful and new approaches are highly warranted. One of the possible solutions is the use of high-energy photons [5].…”

An Uncommon Presentation for Cardiac Melanoma

“…28 This area of slow conduction is the substrate for the reentry mechanism. Circuits may have multiple exit sites 29 or harbor colliding wavefronts. 26 Stevenson et al 29 proposed that a reentry mechanism with multiple exits maintains the PMVT in patients late after myocardial infarction.…”

“…Circuits may have multiple exit sites 29 or harbor colliding wavefronts. 26 Stevenson et al 29 proposed that a reentry mechanism with multiple exits maintains the PMVT in patients late after myocardial infarction. Using computer simulations of figureof-eight circuits, 30 the effects of premature stimuli were simulated at elected sites in the circuit.…”