Radiofrequency ablation of conducting channels identified via electroanatomic voltage mapping suppressed inducibility in 88% of CC-related tachycardias.
Observational (n=26)
Does electroanatomic voltage mapping with tiered decreasing-voltage definition identify conducting channels in scar tissue in patients with chronic MI referred for VT ablation?
Electroanatomic voltage mapping with a tiered decreasing-voltage definition (≤0.2 mV) can identify conducting channels in scar tissue in 75% of patients with SMVT, facilitating targeted ablation.
BACKGROUND: Endocardial mapping before sustained monomorphic ventricular tachycardia (SMVT) induction may reduce mapping time during tachycardia and facilitate the ablation of unmappable VT. METHODS AND RESULTS: Left ventricular electroanatomic voltage maps obtained during right ventricular apex pacing in 26 patients with chronic myocardial infarction referred for VT ablation were analyzed to identify conducting channels (CCs) inside the scar tissue. A CC was defined by the presence of a corridor of consecutive electrograms differentiated by higher voltage amplitude than the surrounding area. The effect of different levels of voltage scar definition, from 0.5 to 0.1 mV, was analyzed. Twenty-three channels were identified in 20 patients. The majority of CCs were identified when the voltage scar definition was or =2 components were recorded more frequently at the inner than at the entrance of CCs (100% versus 75%, P< or =0.01). The activation time of the latest component was longer at the inner than at the entrance of CCs (200+/-40 versus 164+/-53 ms, P< or =0.001). Pacing from these CCs gave rise to a long-stimulus QRS interval (110+/-49 ms). Radiofrequency lesion applied to CCs suppressed the inducibility in 88% of CC-related tachycardias. During a follow-up of 17+/-11 months, 23% of the patients experienced a VT recurrence. CONCLUSIONS: CCs represent areas of slow conduction that can be identified in 75% of patients with SMVT. A tiered decreasing-voltage definition of the scar is critical for CC identification.
Arenal et al. (2004) conducted an observational in Sustained Monomorphic Ventricular Tachycardias (n=26). Electroanatomic voltage mapping and radiofrequency ablation was evaluated on Suppression of inducibility of CC-related tachycardias. Radiofrequency ablation of conducting channels identified via electroanatomic voltage mapping suppressed inducibility in 88% of CC-related tachycardias.