High-power short-duration catheter ablation of atrial fibrillation: is it really a new era? Comparison between new and old radiofrequency contact force-sensing catheters

BACKGROUND

The clinical performance of high-power, short-duration (HPSD) pulmonary vein isolation (PVI) with the novel flexible tip TactiFlex™ (TFSE) catheter, as compared to standard-power, long-duration (SPLD) PVI using the TactiCath™ (TCSE) catheter among patients undergoing catheter ablation (CA) of atrial fibrillation (AF) is currently unknown.

METHODS

We conducted a prospective, observational, single-centre study including 40 consecutive patients undergoing PVI for paroxysmal/persistent AF, using HPSD ablation with the novel TFSE catheter (HPSD/TFSE group). Based on propensity score-matching, forty patients undergoing SPLD PVI with the TCSE catheter were identified (SPLD/TCSE group). In the HPSD/TFSE group, RF lesions were performed by delivering 40-50 W for 10-20 s, while in the SPLD/TCSE group, RF power was 30-35 W, targeting a lesion size index (LSI) of 4.0-5.5. The co-primary study outcomes were time required to complete PVI and first pass isolation (FPI).

RESULTS

PVI was achieved in 100% of patients in both groups, and no major adverse events were observed. Remarkably, PVI time was shorter in the HPSD/TFSE, compared to the SPLD/TCSE group(9 [7-9] min vs. 50 [37-54] min; p < 0.001), while FPI rate was non-significantly higher in the former group(91% [146/160] vs 83% [134/160]; p = 0.063). Shorter procedural (108 [91-120] min vs. 173 [139-187] min, p < 0.001), total RF (9 [7-11] min vs. 43 [32-53] min, p < 0.001), fluoroscopy times(15 [10-19] min vs. 18 [13-26] min, p = 0.014), and lower DAP (1461 [860-2181] vs. 7200 [3400-20,800], p < 0.001) were recorded in the HPSD/TFSE group. A higher average impedance drop was obtained with HPSD/TFSE CA(17[17-18]Ω vs. 16 [15-17] Ω, p < 0.001).

CONCLUSIONS

In our initial clinical experience, HPSD PVI with the TFSE catheter proved faster than SPLD PVI with the TCSE catheter, at least equally effective in terms of FPI, and it was associated with greater impedance drop.

Conduction velocity mapping in Bachmann Bundle using Omnipolar Technology

Funding Acknowledgements

Type of funding sources: None.

Background

Bachmann’s bundle is emerging as a critical component of atrial fibrillation (AF) catheter ablation (CA). The introduction of Omnipolar Technology (OT) in the new Ensite X Cardiac Mapping system, provides three-dimensional information on conduction velocity, activation direction and voltage of endocardial potentials, independently of catheter orientation. OT can create a wave speed map: a color map type coded by numeric value of conduction velocity.

Objective

To assess the feasibility and reliability of left atrium wave speed maps in Bachmann’s bundle identification and conduction velocity characterization.

Methods

We included 10 patients, (60% male, 40% female, mean age 56±8.7 years) undergoing CA for paroxysmal AF at our institution with new Ensite X Cardiac Mapping System; the left atrium (LA) was mapped with the Advisor HD Grid catheter. A sinus rhythm voltage map and wave speed map were obtained and analyzed to identify high conduction velocity areas throughout the Bachmann’s bundle location (septum, roof and left atrium appendage (LAA)).

Results

Wave speed mapping allowed the identification, at the septum, roof and LAA, of a myocardial bundle with greater speed values (2.5±0.3 m/s) with respect to mean atrial value (1±0.1). Pulmonary vein antra conduction velocity mean value was 1.2±0.4 m/s. Standard voltage map (low-voltage areas defined as any LA region with voltage values &lt; 0.5 mV) was compared with wave speed map. Standard voltage map (Figure 1) did not discriminate Bachmann’s bundle, while wave speed map did (Figure 2).

Conclusion

Wave speed mapping introduced by OT is a promising new map type, allowing characterization and identification of Bachmann’s bundle. Further studies are needed to assess the impact of this new technology on procedural workflow and clinical outcome.

High-density substrate mapping of the left ventricle as a guide for endomyocardial biopsy: an omnipolar, bipolar, and cardiac magnetic resonance imaging perspective

Funding Acknowledgements

Type of funding sources: None.

Background

The recent introduction of Omnipolar Technology (OT) has the potential to improve ventricular substrate characterization. In fact, the amplitude of omnipolar electrograms is less dependent of the propagation direction of the recorded wavefront than that of bipolar electrograms, potentially increasing the sensitivity for the detection of viable myocardium by electroanatomical voltage mapping (EVM).

Purpose

To assess the presence and extension of dense scar regions and low-voltage areas in omnipolar voltage (OV) maps of the left ventricle (LV) as compared to standard bipolar endocardial maps and cardiac magnetic resonance (CMR)-derived pixel signal intensity (PSI) maps, among patients undergoing EVM-guided endomyocardial biopsy (EMB).

Methods

The study included 10 patients undergoing LV substrate mapping and EVM-guided EMB at our institution using the Advisor HD Grid mapping catheter. Before the procedure, contrast enhanced-CMR was obtained for each patient and PSI maps were derived from late gadolinium enhancement sequences with the ADAS-VT software. Scar core and border zone areas were measured in PSI endocardial (10-40% of wall thickness) maps and compared to dense scar regions (&lt;0.5 mV) and low-voltage areas (0.5-1.5 mV) measured by standard bipolar endocardial mapping and OV endocardial mapping, respectively. Continuous variables were checked for normality with the Shapiro-Wilk test, and are reported as mean±standard deviation or median [1st-3rd quartile], as appropriate. Statistical comparisons among the three types of mapping (PSI mapping, standard bipolar, and OV) were performed with Friedman test with post-hoc sign test, as appropriate. P values&lt;0.05 were considered statistically significant, and all analyses were performed with the software RStudio.

Results

The indication for EVM-guided EMB was a clinical suspicion of arrhythmogenic or inflammatory cardiomyopathy in all cases. Dense scar regions and low voltage areas detected by OV (dense scar: 2.2 [1.2-6.9] cm2; low voltage areas: 8±3.8 cm2) and standard bipolar mapping (dense scar: 3.4 [2.3-9.6] cm2; low voltage areas: 8.4±4 cm2) were similar to scar core and border zone areas shown by PSI maps (scar core: 1.6[0.6-2.9] cm2; border zone: 3.9[3.7-7.6] cm2; all p=NS). However, dense scar regions were less widespread with OV mapping that with standard bipolar mapping (Friedman test p=0.07; adjusted p=0.006, Figure). The diagnostic yield of EMB measured 80%, whereas mean procedural and fluoroscopy times were 136±30 min and 11±4 min, respectively.

Conclusion

OV mapping allowed a refinement of endocardial substrate maps of the LV as compared to standard bipolar mapping, by reducing the dependency of electrogram amplitude on the direction of propagation, thus allowing the detection of viable myocardium even in bipolar scar regions. Therefore, OV mapping may soon become a preferred approach for EVM-guided EMB.