Outcomes of Catheter Ablation for Ventricular Tachycardia in Structural Heart Disease: A Meta-Analysis and Quality Appraisal of Trials

BACKGROUND: Catheter ablation (CA) of ventricular tachycardia (VT) in patients with structural heart disease is usually reserved for those with recurrent implantable cardioverter defibrillator (ICD) shocks or intolerant to anti-arrhythmic drugs. This meta-analysis synthesizes available trial evidence on CA for VT to clarify the role of this approach. METHODS: MEDLINE, Pubmed, EMBASE and Cochrane were searched for randomised controlled trials (RCTs) of patients with structural heart disease allocated to receive either CA or standard treatment. Outcomes of interest were: all-cause and cardiovascular (CV) mortality, VT recurrence, incidence of appropriate ICD therapy, CV hospitalisations and VT storm. Evidence was appraised using the risk of bias tool and the grading of recommendations assessment, development and evaluation (GRADE) approach. Trial-level pairwise meta-analyses were conducted for all outcomes. Reconstructed time-to-event data meta-analysis was also performed for all-cause mortality. RESULTS: 13 RCTs (N=1,735 patients) were included in the meta-analysis with a follow-up duration of 6–52 months. No significant reduction in all-cause mortality was observed at trial level meta-analysis (risk ratio [RR] 0.87, 95% confidence interval [CI] 0.70–1.08, heterogeneity [I2]=0%), or reconstructed individual patient data meta-analysis (hazard ratio [HR] 0.79, 95%CI 0.57–1.11 at 3 years). However, our pooled estimates, observed effect size and GRADE assessments suggest a potential mortality reduction in the ablation group. Patients who underwent CA experienced a significant reduction in CV hospitalizations (RR 0.78, 95%CI 0.65–0.94, I2=41%), VT storm (RR 0.78, 95%CI 0.63–0.97; I2=5%), VT recurrence (RR 0.83, 95%CI 0.72–0.95, I2=21%), and appropriate ICD therapy (RR 0.74, 95%CI 0.61–0.89, I2=32.5%) compared to control groups. CONCLUSION: A potential all-cause mortality reduction by catheter ablation requires further confirmation in a properly powered RCT. No reduction in cardiovascular mortality was found. VT recurrence, CV hospitalisations, VT storm and ICD therapy were all significantly reduced by catheter ablation in patients with structural heart disease.