Meta-analysis comparing outcomes of catheter ablation for ventricular arrhythmia in ischemic versus nonischemic cardiomyopathy

Pre-ablation and Post-ablation Factors Influencing the Prognosis of Patients with Electrical Storm Treated by Radiofrequency Catheter Ablation: An Update

Catheter ablation-based management strategies for the drug-refractory electrical storm (ES) have been proven to abolish acute ventricular arrhythmic episodes and improve long-term outcomes. However, this effect is highly influenced by multiple independently acting factors, which, if identified and addressed, may allow a more tailored management to each particular case to improve results. This review synthesizes existing evidence concerning ES outcome predictors of patients undergoing ablation and introduces the role of novel scoring algorithms to refine risk stratification. The presence of these factors should be assessed during two distinct phases in relation to the ablation procedure: before (based on preprocedural multimodal evaluation of the patient's structural heart disease and comorbidities) and after the ablation procedure (in terms of information derived from the invasive substrate characterization, procedural results, postprocedural recurrences (spontaneous or during non-invasive testing), and complications).

Catheter ablation versus antiarrhythmic drug therapy for sustained ventricular tachycardia in patients with hypertrophic cardiomyopathy

BACKGROUND

Ventricular tachycardia (VT) is the primary cause of sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM). However, the strategy for VT treatment in HCM patients remains unclear. This study is aimed to compare the effectiveness of catheter ablation versus antiarrhythmic drug (AAD) therapy for sustained VT in patients with HCM.

METHODS

A total of 28 HCM patients with sustained VT at 4 different centers between December 2012 and December 2021 were enrolled. Twelve underwent catheter ablation (ablation group) and sixteen received AAD therapy (AAD group). The primary outcome was VT recurrence during follow-up.

RESULTS

Baseline characteristics were comparable between two groups. After a mean follow-up of 31.4 ± 17.5 months, the primary outcome occurred in 35.7% of the ablation group and 90.6% of the AAD group (hazard ratio [HR], 0.29 [95%CI, 0.10-0.89]; P = 0.021). No differences in hospital admission due to cardiovascular cause (25.0% vs. 71.0%; P = 0.138) and cardiovascular cause-related mortality/heart transplantation (9.1% vs. 50.6%; P = 0.551) were observed. However, there was a significant reduction in the composite endpoint of VT recurrence, hospital admission due to cardiovascular cause, cardiovascular cause-related mortality, or heart transplantation in ablation group as compared to that of AAD group (42.9% vs. 93.7%; HR, 0.34 [95% CI, 0.12-0.95]; P = 0.029).

CONCLUSIONS

In HCM patients with sustained VT, catheter ablation reduced the VT recurrence, and the composite endpoint of VT recurrence, hospital admission due to cardiovascular cause, cardiovascular cause-related mortality, or heart transplantation as compared to AAD.

Sex differences on outcomes of catheter ablation of ventricular tachycardia in patients with structural heart disease: A real-world systematic review and meta-analysis

Background

Sex differences have diversely affected cardiac diseases. Little is known whether these differences impact outcomes of catheter ablation of ventricular tachycardia (VT).

Objectives

To assess the impact of sex differences on outcomes of catheter ablation of VT.

Methods

Databases were searched from inception through December 2021. Effect estimates from individual studies were extracted and combined using the random-effects, generic inverse variance method of DerSimonian and Laird. The outcomes of interest included VT recurrence rates, all-cause mortality, and composite outcomes of mortality, left ventricular assistant device use, and heart transplantation following VT ablation.

Results

Our analysis included 22 observational studies. There were 10,206 patients, of which 12.8% were women. We found no statistical difference between sexes for VT recurrence rate (pooled hazard ratio [HR] 1.04, P = .57, I ² = 14.9%). Similarly, there was statistical difference in neither all-cause mortality nor composite outcomes (pooled HR 0.93, P = .75, I ² = 59.1% and pooled HR 0.9, P = .33, I ² = 0%, respectively). There was a trend toward an increase in women undergoing VT ablation in the recent registries (P = .071).

Conclusion

Our contemporary analysis suggests that sex may have no impact on clinical outcomes of catheter ablation of VT in patients with structural heart disease, though women are the underrepresented. However, recent VT ablation registries have involved more women in their studies. Future studies with a higher proportion of women are encouraged to verify the current perception.

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].

Clinical Outcomes in Patients With Dilated Cardiomyopathy and Ventricular Tachycardia

BACKGROUND

Recurrent ventricular tachycardia (VT) due to dilated cardiomyopathy (DCM) is difficult to treat, and long-term outcome data are limited.

OBJECTIVES

The aim of this study was to identify predictors of mortality or heart transplantation (HTx) and VT recurrence.

METHODS

Consecutive patients with DCM accepted for radiofrequency catheter ablation (RFCA) of VT at 9 centers were prospectively enrolled and followed.

RESULTS

Of 281 consecutive patients (mean age 60 ± 13 years, 85% men, mean left ventricular ejection fraction [LVEF] 36% ± 12%), 35% had VT storm, 20% had incessant VT, and amiodarone was unsuccessful in 68%. During follow-up of 21 months (IQR: 6-30 months), 67 patients (24%) died or underwent HTx, and 138 (49%) had VT recurrence (45 within 30 days, defined as early); the 4-year rate of VT recurrence or mortality or HTx was 70%. Independent predictors of mortality or HTx were early VT recurrence (HR: 2.92; 95% CI: 1.37-6.21; P < 0.01), amiodarone at discharge (HR: 3.23; 95% CI: 1.43-7.33; P < 0.01), renal dysfunction (HR: 1.92; 95% CI: 1.01-3.64; P = 0.046), and LVEF (HR: 1.36; 95% CI: 1.0-1.84; P = 0.052). LVEF ≤32% identified patients at risk for mortality or HTx (area under the curve: 0.75). Mortality or HTx per 100 person-years was 40.4 events after early, compared with 14.2 events after later VT recurrence and 8.5 events with no VT recurrence after RFCA (P < 0.01 for both). Patients with early recurrence and LVEFs ≤32% had a 1-year rate of mortality or HTx of 55%. VT recurrence was predicted by prior implantable cardioverter-defibrillator shocks, basal anteroseptal VT origin, and procedural failure but not LVEF.

CONCLUSIONS

Patients with DCM needing RFCA for VT are a high-risk group. Following RFCA, approximately one-half remain free of VT recurrence. Early VT recurrence with LVEF ≤32% identifies those at very high risk for mortality or HTx, and screening for mechanical support or HTx should be considered. Late VT recurrence after RFCA does not predict worse outcome.

Meta-Analysis of Catheter Ablation Outcomes in Patients With Cardiac Sarcoidosis Refractory Ventricular Tachycardia

Cardiac sarcoidosis (CS) frequently leads to ventricular tachycardia (VT), which is often refractory to antiarrhythmic and/or immunosuppressive medications and requires catheter ablation. We conducted a systematic review and meta-analysis to evaluate the role of catheter ablation in patients with refractory VT undergoing catheter ablation. We searched PubMed, Embase, and Scopus databases from their inception to December 31, 2021 with search terms "cardiac sarcoidosis" AND "electrophysiological studies OR ablation." Fifteen studies were ultimately included for evaluation. Patient demographics, VT mapping, and acute and long-term procedural outcomes were extracted. A total of 15 studies were included in our meta-analysis, with a total of 401 patients, of whom 66% were male, with ages ranging from 39 to 64 years. A total of 95% of patients were on antiarrhythmics and 79% of patients were on immunosuppressants. Left ventricular ejection fraction ranged from 35% to 49% and procedure duration ranged from 269 to 462 minutes. Ablation was reported using both irrigated and nonirrigated catheter tips. A total of 25% of patients (84/339) underwent repeat ablation. Acute procedural success was achieved in 57% (161/285). Procedure complications occurred in 5.7% (17/297) procedures. VT recurrence after first ablation was 55% (confidence interval 48% to 63%, 213/401); VT recurrence after multiple ablations was 37% (81/220). The composite end point of death, heart transplant, and left ventricular assist device implantation was 21% (confidence interval 14% to 30%, 55/297). In conclusion, catheter ablation is a useful modality in patients with CS with refractory VT. However, patients with CS presenting with refractory VT after undergoing VT ablation carry a poor prognosis.

Recent insights into mechanisms and clinical approaches to electrical storm

Electrical storm, characterized by repetitive ventricular tachycardia/fibrillation (VT/VF) over a short period, is becoming commoner with widespread use of implantable cardioverter-defibrillator (ICD) therapy. Electrical storm, sometimes called "arrhythmic storm" or "VT-storm", is usually a medical emergency requiring hospitalization and expert management, and significantly affects short- and long-term outcomes. This syndrome typically occurs in patients with underlying structural heart disease (ischemic or non-ischemic cardiomyopathy) or inherited channelopathies. Triggers for electrical storm should be sought but are often unidentifiable. Initial management is dictated by the hemodynamic status, while subsequent management typically involves ICD interrogation and reprogramming to reduce recurrent shocks, identification/management of triggers like electrolyte abnormalities, myocardial ischemia, or decompensated heart failure, and antiarrhythmic-drug therapy or catheter ablation. Sympathetic nervous system activation is central to the initiation and maintenance of arrhythmic storm, so autonomic modulation is a cornerstone of management. Sympathetic inhibition can be achieved with medications (particularly beta-adrenoreceptor blockers), deep sedation, or cardiac sympathetic denervation. More definitive management targets the underlying ventricular arrhythmia substrate to terminate and prevent recurrent arrhythmia. Arrhythmia targeting can be achieved with antiarrhythmic medications, catheter ablation or more novel therapies such as stereotactic radiation therapy that targets the arrhythmic substrate. Mechanistic studies point to adrenergic activation and other direct consequences of ICD-shocks in promoting further arrhythmogenesis and hypocontractility. Here, we review the pathophysiologic mechanisms, clinical features, prognosis, and therapeutic options for electrical storm. We also outline a clinical approach to this challenging and complex condition, along with its mechanistic basis.

Meta-analysis comparing outcomes of catheter ablation for ventricular arrhythmia in ischemic versus nonischemic cardiomyopathy

Background

Catheter ablation is an effective treatment for ventricular arrhythmia (VA) in ischemic cardiomyopathy (ICM). However, results in non‐ICM (NICM) patients are not satisfactory, and studies comparing differences between NICM and ICM are limited. We conducted a meta‐analysis of procedural characteristics and long‐term outcomes of catheter ablation for VA, comparing results between ICM and NICM.

Methods

Studies in the PubMed, EMBASE, and Cochrane databases were systematically reviewed. Four studies reporting comparison of catheter ablation of VA between ICM and NICM were examined. The Newcastle‐Ottawa Scale was used to appraise study quality. A random‐effects model with inverse variance method was used for comparisons.

Results

Epicardial approach was significantly more undertaken for the NICM group than in the ICM group (odds ratio [OR]: 0.13; 95% confidence interval [CI]: 0.09‐0.18; P < .00001). Mean ablation time (P = .54), fluoroscopy time (P = .55), and procedural time (P = .18) did not differ significantly between the ICM and NICM groups. Procedural failure rates (OR: 0.46; 95% CI: 0.24‐0.89; P = .02) and VA recurrence rates (risk ratio [RR]: 0.68; 95% CI: 0.46‐1.01; P = .06) were significantly higher in the NICM group than in the ICM group. However, all‐cause mortality (RR: 1.37; 95% CI: 0.75‐2.49; P = .31) did not differ significantly between groups.

Conclusions

Procedural failure and VA recurrence rates were significantly higher in the NICM group, despite significantly more frequent epicardial access. These highlight the limitations of catheter ablation for VA in NICM, given our current knowledge.