EnSite^TM OT
Near Field

Peak frequency can be effectively used to characterize scar in atrial fibrillation

PF mapping effectively differentiated between nLVZs (non-low voltage zone), fixed remodeling, and functional remodeling sites. A PF between 215 and 236 Hz was highly predictive of functional remodeling. Thereby, the combination of Omnipolar Voltage and PF measurements in AF will more accurately allow the characterization of the substrate in AF.

Efficacy of the peak frequency map for left atrial posterior wall isolation

In this study, the position of linear ablation of posterior wall was determined based on anatomic (group 1) or Peak Frequency-determined (group 2) locations. The success rate of the LA roof block line targeting the high PF areas was significantly better than that of the conventional anatomical approach. Using a PF map for determining the optimal ablation line for LAPWI is feasible and may increase the probability of completing LAPWI without excess applications within the LAPW.

Optimizing ablation sites for pulmonary vein isolation reconnections: A novel approach using an emphasis map combined with the peak frequency and local activation timing map

In the combined activation timing and peak frequency emphasis group, the number of ablation points required for successful isolation of the PV was significantly lower than in the activation group. The emphasis map enabled objective highlighting of the reconnection sites and facilitated the visual recognition with less unnecessary ablation applications.

The novel automated peak frequency annotation algorithm for identifying high frequency electrogram activity following pulmonary vein isolation in atrial fibrillation ablation

The novel automated PF algorithm complements established mapping criteria and holds the potential to enhance the accuracy of LA mapping during AF ablation. The cutoff values were determined for bipolar and omnipolar voltages and Peak frequency at conduction gaps were as follows: Bipolar 0.20mV and 190.25Hz; Omnipolar 0.32mV and 222.8Hz. Utilizing PF, as opposed to voltage criteria, proves to be more effective in identifying residual activity along circumferential PV ablation lines during AF ablation procedures.

Peak frequency drop: a novel intraprocedural parameter predicting acute conduction gaps postpulmonary vein isolation

This study demonstrates a novel intraprocedural parameter, PF drop, for predicting the acute phase PV gap following PVI. PF maps in patients with a PV gap were analyzed; areas PV gap demonstrated significantly lower PF drop and higher PF post ablation than areas without a gap (-14 ± 43 Hz vs. 61 ± 57 Hz, p < 0.001; 226 ± 49 Hz vs. 176 ± 47 Hz, p < 0.001). The PF drop had the highest predictive value for PV gap among the significant parameters, with a cutoff value of 10.5 Hz, which may be a useful monitoring marker to achieve a durable lesion during PVI.

Peak Frequency Analysis Distinguishes Nearfield from Farfield Signals during Pulmonary Vein Isolation

PF was lower in far-field electrograms than nearfield electrograms. A PF cutoff was selected in an initial cohort and validated in two following cohorts of PAF and PersAF patients. A PF cutoff of 300 Hz had a sensitivity of 93.2% (selection cohort), 90.0% (PAF validation cohort) and 98.6% (PersAF validation cohort), with an overall specificity of 100%. PF analysis improves the recognition of PV isolation.

Differentiation between epicardial and endocardial conduction gaps for left atrial posterior wall isolation using peak frequency annotation algorithm

In this case, a threshold PF value of 200 Hz was the optimal cutoff for the localization of the residual conduction gap. However, the optimal cutoff PF value may differ depending on various factors.

Validation of the peak frequency of bipolar electrograms for detection of residual conduction in atrial scar tissue

Far-field versus near-field frequencies at apparent versus true critical site of PV gap. 28 gaps were found and gap regions showed significantly higher PF. PF better detects residual conduction within an atrial scar region than conventional bipolar voltage. The PF cutoff value for gap discrimination in the PV antra is 240 Hz.

Distribution of peak frequency and omnipolar voltage in electrograms across the atrial body and thoracic veins in a normal heart

Generally, the median peak frequency was significantly higher in the PVs than in the LA (346 [253–441] Hz vs. 323 [262–397] Hz) and in the SVC compared to the RA. Since the timing of the activation of musculatures far from the electrodes, producing far-field electrograms, and the timing of that just below the electrode, producing near-field electrograms, are different, the entire electrograms become fractionated.

Cardioneuroablation guided by real-time spectral analysis: The Omnipolar Technology Near Field

OTNF with PF allows fast and accurate visualization of high frequency atrial areas on a high-density electroanatomic map. This tool may help electrophysiologists to selectively target GPs in the setting of a CNA procedure, avoiding imprecise or over-extensive ablation.

Prognostic value of near-field electrograms at critical ablation sites during ventricular tachycardia ablation

The peak EGM frequency at the VT critical site is a strong predictor of VT recurrence (AUC = 0.81). Notably, the peak frequency at the critical site, as annotated using the Nearfield algorithm, was significantly lower in patients with recurrence compared to those without (192 Hz vs. 397 Hz).

Peak frequency mapping to differentiate near-field from far-field electrograms for ventricular tachycardia ablation: initial results

All areas of VT termination were located in a low voltage and high peak frequency zone. PF mapping apparently identifies slow conduction isthmus and provides complementary information to voltage mapping which can be displayed with emphasis on the electranatomical map.

A novel automated peak frequency annotation algorithm for identifying deceleration zones and ventricular tachycardia ablation sites

PF 220 Hz predicted areas of LAVA, late potential, and deceleration zones targeted for ablation in nearly all cases performed by experienced, high-volume operators. Acquisition of successful ablation targets would have broad implications for patient safety, procedural efficiency, procedural availability, and reimbursement.

Analysis of electrogram peak frequency during ventricular tachycardia ablation: Insights into human tridimensional ventricular tachycardia circuits

High-frequency near-field EGMs (405 Hz) during VT reflect vulnerable areas inside slow conduction isthmus sites. Targeting this area is an independent predictor of rapid VT termination. Areas of frequency >220 Hz within the scar detected during voltage mapping showed a correlation to deceleration zones. Based on our study, EGM PF >405 Hz is a valuable predictor of VT interruption.

Improving substrate mapping for ventricular tachycardia with a novel peak frequency annotation algorithm: Deconstructing the abnormal electrogram

The OTNF algorithm with PF cutoff >220 Hz was applied to a retrospective cohort of 25 patients who underwent VT ablation and ILAM using the standard offset of the latest local bipolar electrogram.The PF technique is fully automated and therefore readily can be used by electrophysiology laboratories broadly and may decrease procedural times as a result of reduced need for manual reannotation.

Detailed Analysis of Electrogram Peak Frequency to guide Ventricular Tachycardia Substrate Mapping

Identification of critical components of the VT isthmus is feasible using substrate-based PF maps to highlight relevant low voltage with an optimal PF threshold of ≥200Hz. Low voltage substrate-based PF mapping during sinus rhythm may identify the critical VT isthmus more accurately than RV pacing. Chronic amiodarone exposure was associated with a lower PF in the isthmus zone during PF mapping of VT.

Near Field Detection and Peak Frequency Metric for Substrate and Activation Mapping of Ventricular Arrhythmias in 2- and 3-Dimensional Circuits

In substrate maps, use of the Nearfiled detection algorithm results in statistically significantly smaller late activating areas compared to last deflection detection and less frequently identified deceleration zones co-locating with the VT isthmus area. For activation maps of scar-related reentry VTs, NF detection allows rapid identification of the VT isthmus without manual reannotation.

Peak frequency analysis and differentiation of near-field from far-field electrograms of the ventricular tachycardia circuit leads to successful ablation of the arrhythmia

PF analysis of the fragmented potentials allowed selection of the site for RF energy application. Clinical ventricular tachycardia was no longer induced during electrophysiological study after ablation.

Comparison of Far-Field and Peak Frequency Electrogram Characteristics at the Earliest Activation Sites during Idiopathic Ventricular Arrhythmias: A novel index to predict ablation success

The nearfield detection algorithm represents the timing of the activation on the endocardial surface. The first component of the EGM at the earliest activation site may reflect a far-field recording from the site of origin. A novel delta first deflection-to-peak frequency electrogram index may predict rapid successful endocardial ablation of outflow tract arrhythmias.

Integration of automated peak frequency annotation with voltage mapping for identifying ventricular tachycardia ablation sites

Peak frequency distributions differed significantly across myocardium conditions. The median peak frequency was 120.0 Hz (77.3–179.0 Hz) in normal voltage myocardium, 145.0 Hz (100.0–194.3 Hz) in low voltage myocardium without late potentials (LPs), and 291.0 Hz (190.3–380.3 Hz) in low-voltage myocardium with late potentials (LPs). In normal voltage areas, no significant differences in PF values were observed between sinus rhythm and RV pacing. These findings suggest that pacing does not significantly alter PF characteristics in either normal or low voltage regions.

Localized three dimensional reentrant ventricular tachycardia visualized by high density mapping in arrhythmogenic right ventricular cardiomyopathy

The successful ablation site had high peak frequencies (≥ 250 Hz), indicating near-field potentials.

Peak frequency mapping in Brugada Syndrome

After ajmaline perfusion, high-density epicardial mapping was performed using the Advisor™ HD Grid Catheter. In addition to LAT and voltage maps, a peak frequency map was obtained. Radiofrequency ablation was performed on the area of late and low-frequency potentials. Remapping after ablation, also under ajmaline, revealed elimination of late potentials on LAT map and elimination of type 1 Brugada pattern. Curiously, although voltage remained above 1.5 mV, no low-frequency areas were highlighted on the map.

Peak frequency analysis for epicardial contact mapping: How (in) frequent is epicardial adipose tissue?

On epicardial maps, low PF values may indicate far-field signals and could indirectly support the identification of sites with epicardial adipose tissue. Semiautomated imaging of epicardial adipose tissue using ADAS is shown as a reference to establish the anatomical epicardial adipose tissue pattern and demonstrates reasonable agreement with the PF map.

Identification of the slow AV nodal pathway by low frequency mapping

A late activation low frequency area of mean 0.92 cm² was found in 18 out of 20 patients. The slow nodal pathway is often located in an area of late activation and low frequency. The mean PF at this area was 175.5 Hz which was significantly lower than the PF recorded at the adjacent atrial area 279.71 Hz.

Comparative utility of omnipolar and bipolar electroanatomic mapping methods to detect and localize dual nodal substrate in patients with atrioventricular nodal reentrant tachycardia

Among quantitative variables, the optimal discriminatory performance for successful Slow Pathway identification was observed using bipolar voltage restricted to a peak frequency >340 Hz (AUC=0.75).

Peak frequency annotation algorithm–guided slow pathway ablation in typical atrioventricular nodal reentrant tachycardia

The high-frequency site of the Tricuspid Valve of the 4–5 o’clock position in the peak frequency map could be a novel target of slow pathway ablation with high safety, efficiency, and efficacy. This peak frequency map–guided approach may help facilitate RF applications with a lower risk of AV block.

Novel near-field detection algorithm–guided slow pathway ablation in atrioventricular nodal reentrant tachycardia

The successful ablation sites in this study displayed relatively low peak frequencies, primarily in the range of 180–210 Hz regardless of the rhythm.

Usefulness of omnipolar technology near field for accessory pathway ablation through the coronary sinus

This novel mapping algorithm for peak frequency analysis of an electrogram using OTNF may be useful for identifying the precise location of the Kent bundle.

High Frequency-Low amplitude electrograms in directionally opposing rhythms are regionally consistent and discriminate sites of atrial tachycardia termination

Paired sinus rhythm (SR) and 500 ms CS paced (CSP) maps were acquired before ablation. High frequency-low voltage CSP discriminated termination region with AUC 0.82 vs. AUC 0.61 based upon Voltage CSP alone. HFLV mapping during either SR or CSP improves specificity to detect the macroreentant atrial arrhythmia with slow conduction zones compared to voltage mapping alone.

Peak Frequency for Characterizing and Predicting Critical Isthmus and Termination Sites in Macro-Re-Entrant Atrial Tachycardia

PF values at termination sites were significantly higher than global PF values and PF within the 5-mm termination diameter. PF values above 363 Hz differentiated global atrial PF from isthmus regions, with values >530 Hz indicating maximum PF at termination sites corresponding to the critical isthmus. Dynamic adjustment of the PF window in each patient allowed best to display regions of maximum PF and to identify the critical isthmus area.

Visualizing the critical isthmus of complex atrial tachycardia using a novel mapping technology of peak frequency duplicate – Initial clinical experience in 2 case reports

By increasing the emphasis map slider value of the PF from 200 Hz to 550 Hz, the authors could distinctly visualize and identify the critical isthmus of the complex AT circuit and evaluate the PV gap, leading to minimal RF applications to treat these tachycardias.

Peak frequency analysis and functional substrate mapping to predict critical isthmus of atypical atrial tachycardia: Findings from a novel automated annotation algorithm to detect near-field signals

The high frequency-low voltage regions correlated well with deceleration zones of ILAM as well as with the successful ablation sites of ATs.

Peak frequency mapping of atypical atrial flutter

All local termination site data had mean PF >150 Hz. 10 of 12 local termination sites (83%) had mean PF >250 Hz, with only 3 of 12 measuring mean PF >350 Hz. 9 of 12 patients (75%) had significantly higher PF near the termination site (all p <.05), and 89% of these sites had significantly lower mean voltage or voltage <0.5mV. PF provides a method of better characterizing and distinguishing critical low-voltage areas.