Catheter Ablation for Ventricular Tachycardia
What is the long-term safety and effectiveness of radiofrequency catheter ablation (RFCA) in patients with coronary artery disease and sustained monomorphic ventricular tachycardia (SMVT)?
Patients underwent RFCA for SMVT associated with coronary artery disease in 18 centers in a prospective, nonrandomized single-arm catheter post-approval study (THERMOCOOL VT). Collected data included cardiovascular-specific adverse events (CSAEs) within 7 days of treatment, 6-month SMVT recurrence, Hospital Anxiety Depression Scale (HADS), long-term (1-, 2-, 3-year) survival, symptomatic VT control, and amiodarone use.
A total of 249 patients, mean age 67 years, were enrolled. The CSAE rate was 3.9% with no strokes. Noninducibility of targeted VT was achieved in 76% of patients. At 6 months, 62% of patients had no SMVT recurrence. The proportion of patients with implantable cardioverter-defibrillator (ICD) shocks decreased from 81% to 27%, the frequency of VT in ICD patients with recurrences was reduced by ≥50% in 64% of patients, and the proportion of normal HADS scores increased from 49% to 69%. Patient-reported VT was 23%, 30%, and 24% at 1, 2, and 3 years. Amiodarone use and hospitalization decreased from 55% and 77% pre-ablation to 18% and 31% at 3 years.
Ablation reduced ICD shocks and VT episodes, and improved anxiety and depression. There was improvement in outcomes, as measured by amiodarone use and hospitalizations.
This was a post-approval study of the safety and efficacy of the ablation catheter, and as such, was an observational cohort study, which left much to the discretion of the operator. There was lack of pre-ablation VT data. ICD programming, which can significantly impact whether or not a patient receives a shock, was not standardized. Long-term outcome data were patient reported. Nonetheless, the report is a description of a multicenter experience, which the field does not abound in. There was a significant reduction in shocks, improvement in the quality of life, and less amiodarone use after ablation compared to before ablation. Unfortunately, in this and other similar studies to date, acute procedural success, expressed as noninducibility of VT at the end of the procedure, did not translate into mortality reduction. At this point, we need randomized multicenter data comparing various ablation strategies and their impact on mortality. The next step would be to ascertain the optimal timing of ablation.
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