Abstract
Introduction
The treatment of ventricular tachycardia (VT) in patients (pts) with ischemic heart disease (IHD) represents a challenge because of its high morbidity and mortality rates and low long-term success rates. In the VANISH clinical trial, 51% of pts undergoing the conventional ablation technique developed within 2 years the combined outcome of mortality or electrical storm (ES) or appropriate CDI shock. The use of high-density substrate maps can lead to greater precision in substrate evaluation and ideally to improved ablation success.
Objectives
To assess the efficacy of substrate-guided ischemic VT ablation using high-density mapping.
Methods
Single-center prospective study of consecutive IHD pts submitted to endocardial ablation of substrate-guided VT using multipolar catheters (PentaRayTM or HDGridTM) and three-dimensional mapping systems with automatic annotation software. The maps were evaluated in order to identify the intra-cicatricial channels (areas of bipolar voltage <1.5mV) in which sequential propagation of local abnormal ventricular activities (LAVAs) were observed, during or after QRS. The ablation strategy aimed at the abolition of all intra-cicatricial LAVAs, directing the radiofrequency applications primarily to the entrances of the channels. The success of ablation was assessed by the primary outcome (death by any cause or ES or appropriate CDI shock) at 2 years and compared to the population of the VANISH study undergoing conventional ablation, using Cox regression and Kaplan- Meier survival analysis.
Results
We included 40 patients, 95% males, 70 ± 8 years, mean ejection fraction 34 ± 10%. 82% on previous amiodarone therapy and 72% were ICD carriers. 32% underwent ablation during hospitalization for ES and 20% had previously undergone VT ablation. The median duration of substrate mapping was 74 minutes, with a mean of 2290 collected points. Major complications were seen in 1 patient (aortic dissection). During a mean follow-up time of 17.3 ± 12.9 months, the long-term success rate of VT ablation was 75%. Additionally, there was a reduction in the proportion of patients receiving amiodarone before vs after ablation (82% vs. 45% respectively). The rate of events observed during follow-up was lower than expected, namely by comparison with the population of the VANISH study undergoing conventional ablation (25% vs 51% at 24 months, HR 0.42 CI 95% 0.2-0.88, p = 0.022), reflecting a relative risk reduction of 58%.
Conclusions
High density mapping allows a detailed characterization of the dysrhythmic substrate in patients with VT in an IHD context. Our results suggest that these technological innovations may be improving the clinical success of VT ablation.
Abstract Figure.
Intraprocedural electrocardiographic imaging of a hemodynamically unstable ischemic ventricular tachycardia originating from the interventricular septum
