Prophylactic catheter ablation of ventricular tachycardia before cardioverter-defibrillator implantation in patients with non-ischemic cardiomyopathy: Clinical outcomes after a single endocardial ablation

Outcomes of early catheter ablation for ventricular tachycardia in adult patients with structural heart disease and implantable cardioverter-defibrillator: An updated systematic review and meta-analysis of randomized trials

Aims

Catheter ablation (CA) for ventricular tachycardia (VT) can improve outcomes in patients with ischemic cardiomyopathy. Data on patients with non-ischemic cardiomyopathy are scarce. The purpose of this systematic review and meta-analysis is to compare early CA for VT to deferred or no ablation in patients with ischemic or non-ischemic cardiomyopathy.

Methods and results

Studies were selected according to the following PICOS criteria: patients with structural heart disease and an implantable cardioverter-defibrillator (ICD) for VT, regardless of the antiarrhythmic drug treatment; intervention–early CA; comparison–no or deferred CA; outcomes–any appropriate ICD therapy, appropriate ICD shocks, all-cause mortality, VT storm, cardiovascular mortality, cardiovascular hospitalizations, complications, quality of life; published randomized trials with follow-up ≥12 months. Random-effect meta-analysis was performed. Outcomes were assessed using aggregate study-level data and reported as odds ratio (OR) or mean difference with 95% confidence intervals (CIs). Stratification by left ventricular ejection fraction (LVEF) was also done. Eight trials (n = 1,076) met the criteria. Early ablation was associated with reduced incidence of ICD therapy (OR 0.53, 95% CI 0.33–0.83, p = 0.005), shocks (OR 0.52, 95% CI 0.35–0.77, p = 0.001), VT storm (OR 0.58, 95% CI 0.39–0.85, p = 0.006), and cardiovascular hospitalizations (OR 0.67, 95% CI 0.49–0.92, p = 0.01). All-cause and cardiovascular mortality, complications, and quality of life were not different. Stratification by LVEF showed a reduction of ICD therapy only with higher EF (high EF OR 0.40, 95% CI 0.20–0.80, p = 0.01 vs. low EF OR 0.62, 95% CI 0.34–1.12, p = 0.11), while ICD shocks (high EF OR 0.54, 95% CI 0.25–1.15, p = 0.11 vs. low EF OR 0.50, 95% CI 0.30–0.83, p = 0.008) and hospitalizations (high EF OR 0.95, 95% CI 0.58–1.58, p = 0.85 vs. low EF OR 0.58, 95% CI 0.40–0.82, p = 0.002) were reduced only in patients with lower EF.

Conclusion

Early CA for VT in patients with structural heart disease is associated with reduced incidence of ICD therapy and shocks, VT storm, and hospitalizations. There is no impact on mortality, complications, and quality of life. (The review protocol was registered with INPLASY on June 19, 2022, #202260080).

Systematic review registration

[https://inplasy.com/], identifier [202260080].

Predictors of recurrence in patients without non-inducibility of ventricular tachycardia at the end of ablation

Background

Ventricular tachycardia (VT) non-inducibility at the end of ablation is associated with a less likely VT recurrence. However, it is not clear whether we should use VT non-inducibility as a routine end point of VT ablation. The aim of this study was to evaluate VT recurrence in patients in whom VT non-inducibility was not achieved at the end of the radiofrequency (RF) ablation and the factors attributing to the VT recurrence.

Methods

We analyzed that 62 patients in whom VT non-inducibility was not achieved at the end of the RF ablation were studied.

Results

Over 2 years, 22 (35%) of the cases had VT recurrences. A multivariate analysis showed that an LVEF ≥35% (HR: 0.19; 95% CI: 0.06-0.49; p < .01) and elimination of the clinical VT as an acute ablation efficacy (HR: 0.23; 95% CI: 0.04-0.81; p = .02) were independent predictors of fewer VT recurrences. RF ablation was associated with a 91.1% reduction in VT episodes.

Conclusion

Even if VT non-inducibility was not achieved, patients with an LVEF ≥35% or in whom the clinical VT could be eliminated might be prevented from having VT recurrences. The validity of the VT non-inducibility of any VT should be evaluated considering each patient's background and the results of the procedure.

Characterization of Lesions Created by a Heated, Saline Irrigated Needle-Tip Catheter in the Normal and Infarcted Canine Heart

BACKGROUND

Inability to eliminate intramural arrhythmogenic substrate may lead to recurrent ventricular tachycardia after catheter ablation. The aim of the present study was to evaluate intramural and full thickness lesion formation using a heated saline-enhanced radiofrequency (SERF) needle-tip catheter, compared with a conventional ablation catheter in normal and infarcted myocardium.

METHODS

Twenty-two adult mongrel dogs (30-40 kg, 15 normal and 7 myocardial infarct group) were studied. Lesions were created using the SERF catheter (40 W/50 °C) or a standard contact force (CF) catheter in both groups.

RESULTS

Comparing SERF to CF ablation, the SERF catheter produced larger lesion volumes than the standard CF catheter-even with >20 g of CF-in both normal (983.1±905.8 versus 461.9±178.3 mm³; P=0.023) and infarcted left ventricular myocardium (1052.3±543.0 versus 340.3±160.5 mm³; P=0.001). SERF catheter lesions were more often transmural than standard CF lesions with >20 g of CF in both groups (59.1% versus 7.7%; P<0.001 and 60.0% versus 12.5%; P=0.017, respectively). Using the SERF catheter, mean depth of ablated lesions reached 90% of the left ventricular wall in both normal and infarcted myocardium.

CONCLUSIONS

The SERF catheter created more transmural and larger ablative lesions in both normal and infarcted canine myocardium. SERF ablation is a promising new approach for endocardial intramural and full thickness ablation of ventricular tachycardia substrate that is not accessible with current techniques.

Preventive Ventricular Tachycardia Ablation in Patients with Ischaemic Cardiomyopathy: Meta-analysis of Randomised Trials

Catheter ablation of ventricular tachycardia (VT) aims to treat the underlying arrhythmia substrate to prevent ICD therapies. The aim of this meta-analysis was to assess the safety and efficacy of VT ablation prior to or at the time of secondary prevention ICD implantation in patients with coronary artery disease, as compared with deferred VT ablation. Based on a systematic literature search, three randomised trials were considered eligible for inclusion in this analysis, and data on the number of patients with appropriate ICD shocks, appropriate ICD therapy, arrhythmic storm, death and major complications were extracted from each study. On pooled analysis, there was a significant reduction of appropriate ICD shocks (OR 2.58; 95% CI [1.54–4.34]; p<0.001) and appropriate ICD therapies (OR 2.04; 95% CI [1.15–3.61]; p=0.015) in patients undergoing VT ablation at the time of ICD implantation without significant differences with respect to complications (OR 1.39; 95% CI [0.43–4.51]; p=0.581). Mortality did not differ between both groups (OR 1.30; 95% CI [0.60–2.45]; p=0.422). Preventive catheter ablation of VT in patients with coronary heart disease at the time of secondary prevention ICD implantation results in a significant reduction of appropriate ICD shocks and any appropriate ICD therapy compared with patients without or with deferred VT ablation. No significant difference with respect to complications or mortality was observed between both treatment strategies.

Prophylactic catheter ablation of ventricular tachycardia in ischemic cardiomyopathy: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Catheter ablation is proven to be an effective strategy for drug refractory ventricular tachycardia (VT) in ischemic cardiomyopathy. However, the appropriate timing of VT ablation and identifying the group of patients that may receive the greatest benefit remains uncertain. There is limited data on the effect on prophylactic catheter ablation (PCA) in the prevention of implantable cardioverter defibrillator (ICD) therapy, electrical storm, and mortality.

METHODS

We performed a comprehensive literature search through November 1, 2017, for all eligible studies comparing PCA + ICD versus ICD only in eligible patients with ischemic cardiomyopathy. Clinical outcomes included all ICD therapies including ICD shocks and electrical storm. Additional outcomes included all-cause mortality, cardiovascular mortality, and complications.

RESULTS

Three randomized controlled trials (RCTs) (N = 346) met inclusion criteria. PCA was associated with a significantly lower ICD therapies (OR 0.49; CI 0.28 to 0.87; p = 0.01) including ICD shocks [OR 0.38; CI 0.22 to 0.64; p = 0.0003) and electrical storm (OR 0.55; CI 0.30 to 1.01; p = 0.05) when compared with ICD only. There was no significant difference in all-cause mortality (OR 0.77; CI 0.41 to 1.46; p = 0.42), cardiovascular mortality (OR 0.49; CI 0.16 to 1.50; p = 0.21), and major adverse events (OR 1.45; CI 0.52 to 4.01; p = 0.47) between two groups.

CONCLUSION

These results suggest prophylactic catheter ablation decreases ICD therapies, including shocks and electrical storm with no improvement in overall mortality. There is a need for future carefully designed randomized clinical trials.

[Epicardial ablation of ventricular tachycardias]

Ventricular tachycardias (VT) in patients with structural heart diseases have predominantly a scar-associated reentry mechanism so that substrate-based ablation approaches also have to be used in nearly all procedures. In many VT cases-especially in nonischemic cardiomyopathy (NICM) and arrhythmogenic right ventricular cardiomyopathy-a critical epicardial substrate can be identified as an essential component of the reentry circuit so that for the ablation-based modification of the substrate in these cases an epicardial approach is necessary. In cases of redo-VT ablation procedures in ischemic cardiomyopathy (after a previously endocardial ablation), an epicardial approach should also be considered. There are also cases in whom no endocardial substrate can be identified and an isolated epicardial substrate can be identified. Worldwide epicardial VT ablations are usually performed after gaining epicardial access using subxyphoidal puncture. The results of recent studies show a higher efficiency with stabilization of cardiac rhythm and reduction of recurrent VT episodes (about 70% event-free survival at the 2‑year follow-up) after endo-plus epicardial substrate modification. In electrical storm cases, an early epicardial VT ablation approach also appears to be relevant, especially in NICM. Epicardial instrumentation and ablation represents a complex procedure which should only be performed in experienced centers with cardiac surgery back-up. In these experienced centers, the complications rate is less than 5%.

Can ventricular tachycardia non-inducibility after ablation predict reduced ventricular tachycardia recurrence and mortality in patients with non-ischemic cardiomyopathy? A meta-analysis of twenty-four observational studies

BACKGROUND

At present, the role of ventricular tachycardia (VT) non-inducibility after ablation in patients with non-ischemic cardiomyopathy (NICM) remains controversial. We conducted a meta-analysis of the published literature to assess whether VT non-inducibility after ablation could predict reduced VT recurrence and mortality in patients with NICM.

METHODS

PubMed, ScienceDirect, and the Cochrane library were searched for studies evaluating the effects of VT non-inducibility after catheter ablation on the long-term outcome in NICM patients with sustained VT. Results were analyzed using a fixed-effect model, and the data were pooled using RevMan 5.3 software.

RESULTS

Twenty-four observational studies were identified (736 participants, mean follow-up time: 22months). NICM patients with VT inducibility after ablation had a higher risk of VT recurrence (odds ratio [OR]=5.83, 95% confidence interval [CI] 4.07-8.37; P<0.00001) and all-cause mortality (OR=3.55, 95% CI 1.62-7.78; P=0.002) compared with VT non-inducibility. Similarly in the subgroup analysis, patients with VT inducibility showed a higher risk of VT recurrence from non-ischemic dilated cardiomyopathy (OR=3.92, 95% CI 2.36-6.50; P<0.00001) and arrhythmogenic right ventricular dysplasia/cardiomyopathy (OR=5.37, 95% CI 2.20-13.10; P=0.0002). Additionally, meta-analysis also showed that combined endo-epicardial ablation significantly reduced the risk of VT recurrence compared with endocardial-only ablation (OR=2.02, 95% CI 1.19-3.44; P=0.009; mean follow-up time: 22months).

CONCLUSION

Recent evidence has shown that VT non-inducibility after ablation is a predictor for reduced VT recurrence and mortality compared with VT inducibility in NICM patients with sustained VT. In addition, endocardial plus adjuvant epicardial ablation provides better long-term arrhythmia-free survival than endocardial ablation alone.