Future Perspectives and New "Frontiers" in Cardiac Rhythmology

A case report of long-term successful stereotactic arrhythmia radioablation in a cardiac contractility modulation device carrier with giant left atrium, including a detailed dosimetric analysis

Introduction

Catheter ablation (CA) is the current standard of care for patients suffering drug-refractory monomorphic ventricular tachycardias (MMVTs). Yet, despite significant technological improvements, recurrences remain common, leading to increased morbidity and mortality. Stereotactic arrhythmia radioablation (STAR) is increasingly being adopted to overcome the limitations of conventional CA, but its safety and efficacy are still under evaluation.

Case presentation

We hereby present the case of a 73-year-old patient implanted with a mitral valve prosthesis, a cardiac resynchronization therapy-defibrillator, and a cardiac contractility modulation device, who was successfully treated with STAR for recurrent drug and CA-resistant MMVT in the setting of advanced heart failure and a giant left atrium. We report a 2-year follow-up and a detailed dosimetric analysis.

Conclusion

Our case report supports the early as well as the long-term efficacy of 25 Gy single-session STAR. Despite the concomitant severe heart failure, with an overall heart minus planned target volume mean dosage below 5 Gy, no major detrimental cardiac side effects were detected. To the best of our knowledge, our dosimetric analysis is the most accurate reported so far in the setting of STAR, particularly for what concerns cardiac substructures and coronary arteries. A shared dosimetric planning among centers performing STAR will be crucial in the next future to fully disclose its safety profile.

Effect of Sacubitril/Valsartan on Reducing the Risk of Arrhythmia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background and Objective

Relevant data of PARADIGM-HF reveals sacubitril/valsartan (SV) therapy led to a greater reduction in the risks of arrhythmia, and sudden cardiac death than angiotensin converting enzyme inhibitor (ACEI)/angiotensin receptor inhibitor (ARB) therapy in HFrEF, however, inconsistent results were reported in subsequent studies. Here, we conduct a meta-analysis of related randomized controlled trials (RCTs) to evaluate the protective effect of SV on reducing the risk of arrhythmias.

Methods and Results

RCTs focused on the difference in therapeutic outcomes between SV and ACEI/ARB were searched from PUBMED, EMBASE, ClinicalTrials.gov, and Cochrane Library. The results were extracted from each individual study, expressed as binary risk, 95% confidence interval (CI) and relative risk (RR). Sixteen RCTs including 22, 563 patients met the study criteria. Compared with ACEI/ARB therapy, SV therapy did significantly reduce in the risks of severe arrhythmias among patients with heart failure with reduced ejection fraction (HFrEF) (RR 0.83, 95% CI 0.73–0.95, p = 0.006), ventricular tachycardia (VT) among patients with HFrEF (RR 0.69, 95% CI 0.51–0.92, p = 0.01), cardiac arrest among patients with heart failure (HF) (RR 0.52, 95% CI 0.37–0.73, p = 0.0002), cardiac arrest among patients with HFrEF (RR 0.49, 95% CI 0.32–0.76, p = 0.001), cardiac arrest or ventricular fibrillation (VF) among patients with HF (RR 0.63, 95% CI 0.48–0.83, p = 0.001), and cardiac arrest or VF among patients with HFrEF (RR 0.65, 95% CI 0.47–0.89, p = 0.008), but reduced the risks of arrhythmias (RR 0.87, 95% CI 0.74–1.01, p = 0.07), atrial arrhythmias (RR 0.98, 95% CI 0.83–1.16, p = 0.85), and atrial fibrillation (RR 0.98, 95% CI 0.82–1.17, p = 0.82) among all patients with no significant between-group difference. The merged result was robust after sensitivity analysis, and there was no publication bias.

Conclusion

Our meta-analysis provides evidence that, compared with ACEI/ARB, SV can additionally reduce the risks of most arrhythmias, just the significant differences are revealed in reducing the risks of VT, severe arrhythmias, and cardiac arrest in patients with HFrEF. Besides, the positive effect of SV on VF according to statistical result of combining VF with cardiac arrest in patients with HFrEF is credibility.

Minimal fluoroscopy approach for right-sided supraventricular tachycardia ablation with a novel ablation technology: Insights from the multicenter CHARISMA clinical registry

BACKGROUND

No data exist on the ability of the novel Rhythmia 3-D mapping system to minimize fluoroscopy exposure during transcatheter ablation of arrhythmias. We report data on the feasibility and safety of a minimal fluoroscopic approach using this system in supraventricular tachycardia (SVT) procedures.

METHODS

Consecutive patients were enrolled in the CHARISMA registry at 12 centers. All right-sided procedures performed with the Rhythmia mapping system were analyzed. The acquired electroanatomic information was used to reconstruct 3-D cardiac geometry; fluoroscopic confirmation was used whenever deemed necessary.

RESULTS

Three hundred twenty-five patients (mean age = 56 ± 17 years, 57% male) were included: 152 atrioventricular nodal reentrant tachycardia, 116 atrial flutter, 41 and 16 right-sided accessory pathway and atrial tachycardia, respectively. Overall, 27 481 s of fluoroscopy were used (84.6 ± 224 s per procedure, equivalent effective dose = 1.1 ± 3.7 mSv per patient). One hundred ninety-two procedures (59.1%) were completed without the use of fluoroscopy (zero fluoroscopy, ZF). In multivariate analysis, the presence of a fellow in training (OR = 0.15, 95% CI: 0.05-0.46; p = .0008), radiofrequency application (0.99, 0.99-1.00; p = .0002), and mapping times (0.99, 0.99-1.00; p = .042) were all inversely associated with ZF approach. Acute procedural success was achieved in 97.8% of the cases (98.4 vs. 97% in the ZF vs. non-ZF group; p = .4503). During a mean of 290.7 ± 169.6 days follow-up, no major adverse events were reported, and recurrence of the primary arrhythmia was 2.5% (2.1 vs. 3% in the ZF vs. non-ZF group; p = .7206).

CONCLUSIONS

The Rhythmia mapping system permits transcatheter ablation of right-sided SVT with minimal fluoroscopy exposure. Even more, in most cases, the system enables a ZF approach, without affecting safety and efficacy.