BACKGROUND: Frequent premature ventricular contractions (PVCs) in children are usually considered benign. Symptoms and left ventricular dysfunction are indications for treatment with antiarrhythmic drugs.
OBJECTIVE: This study aimed to evaluate the efficacy of flecainide vs metoprolol in reducing PVCs in children.
METHODS: A randomized open-label crossover trial was conducted of children with a PVC burden of >15% on Holter monitoring successively treated with metoprolol and flecainide, or vice versa, with a drug-free interval of at least 2 weeks. Holter measurements were repeated before and after the start of the antiarrhythmic drug.
RESULTS: Sixty patients were screened; 19 patients could be included. Median age was 13.9 years (interquartile range, 5.5 years). Mean baseline PVC burden was 21.7% (n = 18; SD ± 14.0) before the start of flecainide and 21.2% (n = 17; SD ± 11.5) before the start of metoprolol. In a mixed model analysis, the estimated mean reduction in PVC burden was 10.6 percentage points (95% CI, 5.8-15.3) for flecainide and 2.4 percentage points (95% CI,2.7-7.5) for metoprolol, with a significant difference of 8.2 percentage points (95% CI, 0.86-15.46; P = .031). Exploratory analysis revealed that 9 of 18 patients treated with flecainide and 1 of 17 patients treated with metoprolol had a reduction to a PVC burden below 5%. No discriminating factors between flecainide responders and nonresponders were found; the mean plasma level was not significantly different (0.34 mg/L vs 0.52 mg/L; P = .277).
CONCLUSIONS: In children with frequent PVCs, flecainide led to a significantly greater reduction of PVC burden compared with metoprolol. Flecainide was effective in only a subgroup of patients, which appears to be unrelated to the plasma level.

We aim to evaluate whether the use of a multielectrode mapping catheter could lead to higher efficacy of premature ventricular contraction (PVC) ablation.
Prospective, multicenter nonrandomized study of consecutive patients referred for PVC ablation from January 2018 to June 2021. Patients were separated into two groups: activation map performed with the PentaRay catheter (Study group) or with the ablation catheter (Control group). PMF software was used in both groups. Procedural endpoints and 1-year freedom from ventricular arrhythmia were assessed.
During the enrollment period 136 patients (60% males, mean age of 55 ± 17 years, 60% left-sided origin) fulfilled the inclusion criteria - 68 patients in each group. Patients in the Study Group had a sevenfold higher number of acquired activation points (768 ± 728 vs. 110 ± 79, p < 0.01), a shorter mapping time (28 ± 19 min vs. 49 ± 32 min, p < 0.01) and a quicker procedure time (110 ± 33 min vs. 134 ± 50 min, p < 0.01), compared to patients in the Control Group. While there were no significant differences in the acute success (95.6% in the Study Group vs. 90.1% in Control group, p = 0.49), or adverse events (4% in the Study group vs. 7% in the Control group, p = 0.72), patients in the Study group had a higher freedom from ventricular arrhythmia at 1-year (89.7% vs. 70.6%, p = 0.01). The use of the PentaRay catheter was an independent predictor of success (HR = 6.20 [95% CI, 1.08-35.47], p = 0.003).
The use of the PentaRay catheter may improve the outcome of PVC ablation while reducing procedure time.

UNASSIGNED: We sought to assess the efficacy, safety and short-term clinical outcome of very high-power short-duration (vHP-SD) radiofrequency (RF) catheter ablation for the treatment of idiopathic PVCs originating from the cardiac outflow tract (OT).
UNASSIGNED: Power-controlled RF ablation is a widely used technique for the treatment of premature ventricular contractions (PVCs). A novel ablation catheter offers three microelectrodes and six thermocouples at its tip and provides temperature-controlled vHP-SD (90 Watts/4 s,) with the opportunity to switch to moderate-power mode.
UNASSIGNED: In this pilot study, twenty-four consecutive, prospectively enrolled patients underwent PVC ablation utilizing the vHP-SD ablation (study group) and were compared with 24 consecutive patients previously treated with power-controlled ablation (control group). Each group included 12 patients with PVCs originating from the right ventricular OT (RVOT) and 12 patients with PVCs originating from the left ventricular OT (LVOT). The acute endpoint was PVC elimination and was achieved in all patients.
UNASSIGNED: In 16/24 (67%) patients (study group) it was achieved by using vHP-SD only. The median RF delivery time was 52 (interquartile range [IQR] 16, 156) seconds (study group) and 350 (IQR 240, 442) seconds (control group, p < 0.0001). No difference was observed regarding procedure duration (p = 0.489) as well as 6-months follow-up (p = 0.712). One (4%, study group) and 2 (8%, control group) severe adverse events occured (p = 0.551).
UNASSIGNED: In this study, vHP-SD PVC ablation was similarly effective and safe as compared to conventional power-controlled ablation. The RF time was significantly shorter.

Accurate localization of premature ventricular contractions (PVC) focus is a prerequisite to successful catheter ablation.
The objective was to evaluate the software View Into Ventricular Onset (VIVO) accuracy at locating the anatomical origins for premature ventricular contractions. The VIVO device noninvasively creates a model of the patient\'s heart and torso, with exact locations of 12‑lead ECG electrodes, and applies a mathematical algorithm from surface signals to determine the origin of the arrhythmia. We sought to compare the agreement between VIVO-predicted locations to invasive electroanatomical mapping results.
51 consecutive patients who presented for PVC ablations at the study centers were recruited. VIVO images were collected at baseline preprocedure and all patients underwent invasive electroanatomical activation mapping of the clinical arrhythmia. Pacing was performed in pre-specified locations in the right and/or left ventricle. The successful sites of ablation and the pacing locations were compared to VIVO predicted locations. The results were adjudicated by physician experts in a blinded fashion.
Seven patients were excluded from analyses. VIVO accurately identified the origin of the clinical premature ventricular contractions in 44/44 patients (100.00%). The accuracy in identifying the paced location for all patients (right and left sides of the heart) was 99.5% using the VIVO system. No adverse events were reported.
VIVO is a novel noninvasive system that could be used to help guide ablation procedures with a high degree of accuracy. The VIVO algorithm is easy to use and may be useful in the workflow for ventricular arrhythmia ablation.

The moderator band (MB) is an endocavitary structure with only 2 exits to the bulk of the ventricular myocardium. Whether this may lead to specific electrophysiological characteristics remains unknown.
The purpose of this study was to investigate electrocardiographic (ECG), activation, and pace mapping characteristics of MB-originated ventricular arrhythmias (VAs).
Mapping and ablation of MB-VAs were performed in 12 patients under the guidance of a 3-dimensional electroanatomic mapping system and intracardiac echocardiography and ECG, and mapping data were analyzed. Of these patients, 11 underwent pace mapping study of 6 sites around the MB and the QRS morphology was compared.
The earliest activation site was free wall (FW) insertion in 8 patients (66.7%) and MB body in 4 patients (33.3%), preceding the QRS onset by 17.8±4.7 ms, and Purkinje-like potential was observed in 6 (50.0%). VAs were eliminated at the earliest activation site in the procedure, but recurrence was documented in 2 cases (16.7%) during a follow-up of 13.4±7.8 months. Pacing QRS complex from the MB was characterized by short QRS duration (P<.001), short intrinsicoid deflection time (P<.001), later precordial transition (P=.025), and notch on the descending limb of the inferior leads (P<.001) as compared with pacing from the adjacent anterior-lateral FW, and that notch could also differentiate MB from the anterior papillary muscle (P=.027). However, pacing QRS is identical between the MB body and the FW insertion in 11 of 11 patients and between the septal insertion and the MB body in 7 of 11 patients.
Bidirectional conduction via the 2 exits during MB-VAs contributed to distinct ECG and electrophysiological characteristics, while pace mapping is of limited value in defining the ablation target.

OBJECTIVE: ECVUE™ technology, a novel, three-dimensional, non-invasive mapping system, offers a unique arrhythmia characterization and localization. We sought to evaluate the clinical impact of this system in routine clinical mapping and ablation of ventricular arrhythmias (VAs).
RESULTS: Patients with monomorphic premature ventricular contractions with or without monomorphic ventricular tachycardia were enrolled prospectively and randomized into two groups: ventricular ectopy localization using either 12-lead electrocardiogram (ECG) algorithms or with ECVUE™, followed by conventional guided ablation. Forty-two patients were enrolled in the study. The ECVUE™ system accurately identified both the chamber and sub-localized the VA origin in 20 of 21 (95.2%) patients. In contrast, using 12-lead ECG algorithms, the chamber was accurately diagnosed in 16 of 21 (76.2%) patients, while the arrhythmia origin in only 8 of 21 (38.1%), (P = 0.001 vs. ECVUE™). Acute success in ablation was achieved in all patients. Regarding the number of radiofrequency-energy applications (in total 2 vs. 4, P = 0.005) in the ECVUE™ arm, ablation was more precise than the ECG group which used standard of care activation and pace mapping-guided ablation. Three months success in ablation was 95.2% for the ECVUE™ and 100% for the ECG group (P = ns). Time to ablation was 35.3 min in the conventional arm and 24.4 min in ECVUE Group, (P = 0.035). The X-ray radiation exposure was 3.21 vs. 0.39 mSv, P = 0.001 for the ECVUE™ group and ECG group.
CONCLUSIONS: ECVUE™ technology offers a clinically useful tool to map VAs with high accuracy and more targeted ablations superior to the body surface ECG but had significantly higher radiation exposure due to computed tomography scan.

BACKGROUND: Although several reports address characteristic 12-lead electrocardiographic findings of outflow tract ventricular arrhythmias (OT-VAs), the accuracy of electrocardiogram-based algorithms to predict the OT-VA origin is sometimes limited.
OBJECTIVE: This study aimed to develop a magnetocardiography (MCG)-based algorithm using a novel adaptive spatial filter to differentiate between VAs originating from the aortic sinus cusp (ASC-VAs) and those originating from the right ventricular outflow tract (RVOT-VAs).
METHODS: This study comprised 51 patients with an OT-VA as the target of catheter ablation. An algorithm was developed by correlating MCG findings with the successful ablation site. The arrhythmias were classified as RVOT-VAs or ASC-VAs. Three parameters were obtained from 3-dimensional MCG imaging: depth of the origin of the OT-VA in the anteroposterior direction; distance between the earliest atrial activation site, that is, sinus node, and the origin of the OT-VA; and orientation of the arrhythmia propagation at the QRS peak. The distance was indexed to the patient\'s body surface area (in mm/m2).
RESULTS: Origins of ASC-VAs were significantly deeper (81 ± 6 mm/m(2) vs. 68 ± 8 mm/m(2); P < .01) and farther from the sinus node (55 ± 9 mm/m2 vs. 41 ± 9 mm/m(2); P < .01) than those of RVOT-VAs. ASC-VA propagation had a tendency toward rightward axis. Receiver operating characteristic analyses determined that the depth of the origin was the most powerful predictor, with a sensitivity of 90% and a specificity of 73% (area under the curve = 0.90; P < .01). Discriminant analysis combining all 3 parameters revealed the accuracy of the localization to be 94%.
CONCLUSIONS: This MCG-based algorithm appeared to precisely discriminate ASC-VAs from RVOT-VAs. Further investigation is required to validate the clinical value of this technique.

BACKGROUND: It is unknown whether radiofrequency ablation (RFA) or antiarrhythmic therapy is superior when treating patients with symptomatic premature ventricular contractions (PVCs).
OBJECTIVE: To determine the relative efficacy of RFA and antiarrhythmic drugs (AADs) on PVC burden reduction and increasing left ventricular systolic function.
METHODS: Patients with frequent PVCs (>1000/24 h) were treated either by RFA or with AADs from January 2005 through December 2010. Data from 24-hour Holter monitoring and echocardiography before and 6-12 months after treatment were compared between the 2 groups.
RESULTS: Of 510 patients identified, 215 (40%) underwent RFA and 295 (60%) received AADs. The reduction in PVC frequency was greater by RFA than with AADs (-21,799/24 h vs -8,376/24 h; P < .001). The left ventricular ejection fraction (LVEF) was increased significantly after RFA (53%-56%; P < .001) but not after AAD (52%- 52%; P = .6) therapy. Of 121 (24%) patients with reduced LVEF, 39 (32%) had LVEF normalization to 50% or greater. LVEF was restored in 25 of 53 (47%) patients in the RFA group compared with 14 of 68 (21%) patients in the AAD group (P = .003). PVC coupling interval less than 450 ms, less impaired left ventricular function, and RFA were independent predictors of LVEF normalization performed by using multivariate analysis.
CONCLUSIONS: RFA appears to be more effective than AADs in PVC reduction and LVEF normalization.