Long-term outcome of ventricular tachycardia ablation in patients who did not undergo programmed electrical stimulation after ablation.

BACKGROUND: Ventricular arrhythmia inducibility is one of the ideal endpoints of ventricular tachycardia (VT) ablation. However, it may be challenging to implement programmed electrical stimulation (PES) at the end of the procedure under several circumstances. The long-term outcome of patients who did not undergo PES after VT ablation remains largely unknown. PURPOSE: To investigate the details and long-term outcome of VT ablation in patients who did not undergo PES at the end of the ablation procedure. METHODS: Among 183 VT ablation procedures in patients with structural heart disease who underwent VT ablation using an irrigated catheter, we enrolled those who did not undergo PES after VT ablation. VT ablation strategy involved targeting clinical VT plus pacemap-guided substrate ablation if inducible. When VT was not inducible, substrate-based ablation was performed. The primary endpoint was VT recurrence. RESULTS: In 58 procedures, post-ablation VT inducibility was not assessed. The causes were non-inducibility of sustained VT before ablation (27/58, 46.6%), long procedure time (27.6%, mean 392 min), complications (10.3%), intolerant hemodynamic state (10.3%), and inaccessible or unsafe target (6.9%). With regard to the primary endpoint, 23 recurrences (39.7%) were observed during a mean follow-up period of 2.5 years. Patients with non-inducibility before ablation showed less VT recurrences (4/27, 14.8%) during follow-up than patients with other causes of untested PES after ablation (19/31, 61.2%) (Log-rank < 0.001). CONCLUSIONS: VT recurrence was not observed in approximately 60% of the patients who did not undergo PES at the end of the ablation procedure. PES after VT ablation may be not needed among patients with pre-ablation non-inducibility.

Gene therapy to terminate tachyarrhythmias.

INTRODUCTION: To date, the treatment option for tachyarrhythmia is classified into drug therapy, catheter ablation, and implantable device therapy. However, the efficacy of the antiarrhythmic drugs is limited. Although the indication of catheter ablation is expanding, several fatal tachyarrhythmias are still refractory to ablation. Implantable cardioverter-defibrillator increases survival, but it is not a curable treatment. Therefore, a novel therapy for tachyarrhythmias refractory to present treatments is desired. Gene therapy is being developed as a promising candidate for this purpose, and basic research and translational research have been accumulated in recent years. AREAS COVERED: This paper reviews the current state of gene therapy for arrhythmias, including susceptible arrhythmias, the route of administration to the heart, and the type of vector to use. We also discuss the latest progress in the technology of gene delivery and genome editing. EXPERT OPINION: Gene therapy is one of the most promising technologies for arrhythmia treatment. However, additional technological innovation to achieve safe, localized, homogeneous, and long-lasting gene transfer is required for its clinical application.

Novel mapping algorithm during catheter ablation for ventricular parasystole originating from left anterior fascicle.

A 17-year-old woman presented with frequent palpitations and shortness of breath and was diagnosed with drug-refractory ventricular parasystole. We predicted that the parasystole originated from the left anterior fascicle (LAF). Detailed activation maps of both conduction systems, including the LAF, during sinus rhythm and ventricular parasystole were obtained using a parallel mapping system. We confirmed the earliest fascicular potential of the parasystole and performed catheter ablation with no complications. This novel mapping algorithm for simultaneous acquisition of multiple maps aided effective treatment of ventricular parasystole originating from the LAF.

Recurrent ischemic stroke in patients with atrial fibrillation ablation and prior stroke: A study based on etiological classification.

BACKGROUND: Different subtypes of ischemic stroke may have different risk factors, clinical features, and prognoses. This study investigated the incidence and mode of stroke recurrence in patients with a history of stroke who underwent atrial fibrillation (AF) ablation. METHODS: Of 825 patients who underwent AF ablation from 2006 to 2016, 77 patients (9.3%, median age 69 years) with a prior ischemic stroke were identified. Patients were classified as those with prior cardioembolic (CE) stroke (n = 55) and those with prior non-CE stroke (n = 22). The incidence and pattern of stroke recurrence were investigated. RESULTS: The incidence of asymptomatic AF (54.5% vs 22.7%; P = .011) and left atrial volume (135.8 mL vs 109.3 mL; P = .024) was greater in the CE group than in the non-CE group. Anticoagulation treatment was discontinued at an average of 28.1 months following the initial ablation in 34 (44.2%) patients. None of the patients developed CE stroke during a median 4.1-year follow-up. In the non-CE group, 2 patients experienced recurrent non-CE stroke (lacunar infarction in 1 and atherosclerotic stroke in 1); however, AF was not observed at the onset of recurrent ischemic stroke. CONCLUSIONS: In patients with a history of stroke who underwent catheter ablation for AF, the incidence of recurrent stroke was 0.54/100 patient-years. The previous stroke in these patients may not have been due to AF in some cases; therefore, a large-scale prospective study is warranted to identify the appro priate antithrombotic therapy for the prevention of potentially recurrent stroke.