Comparison of voltage maps using OCTARAY catheter and PENTARAY catheter.

BACKGROUND: Recently, a new OCTARAY® mapping catheter was commercially launched. The catheter is designed to enable high-density mapping and precise signal recording via 48 small electrodes arranged on eight radiating splines. The purpose of this study was to compare bipolar voltage and low-voltage-area size, and mapping efficacy between the OCTARAY catheter and the PENTARAY® catheter METHODS: Twelve consecutive patients who underwent initial and second ablations for persistent atrial fibrillation within 2 years were considered for enrollment. Voltage mapping was performed twice, first during the initial ablation using the PENTARY catheter and second during the second ablation using the OCTARAY Long 3-3-3-3-3 (L3) catheter. RESULTS: Mean voltage with the OCTARAY-L3 catheter (1.64 ± 0.57 mV) was 32.3% greater than that with the PENTARAY catheter (1.24 ± 0.46 mV, p < .0001) in total left atrium. Low-voltage-area (<0.50 mV) size with the OCTARAY-L3 catheter was smaller than that with the PENTARAY catheter (6.9 ± 9.7 vs. 11.4 ± 13.0 cm2 , p < .0001). The OCTARAY-L3 catheter demonstrated greater efficacy than the PENTARAY catheter in terms of shorter mapping time (606 ± 99 vs. 782 ± 211 s, p = .008) and more mapping points (3,026 ± 838 vs. 781 ± 342 points, p < .0001). CONCLUSION: The OCTARAY catheter demonstrated higher voltage recordings, narrower low-voltage areas, and a more efficacious mapping procedure than the PENTARAY catheter.

Impact of Longer Hemodialysis Vintage with Higher Serum Phosphorus Level on Clinical Outcomes in Patients with Chronic Limb-Threatening Ischemia Presenting Tissue Loss after Endovascular Therapy.

AIMS: Hemodialysis vintage and serum phosphorus levels adversely affect outcomes in patients on hemodialysis. Whether these factors have a similar prognostic impact on patients who are on hemodialysis and have chronic limb-threatening ischemia (CLTI) has not been systematically studied. We aimed to explore the risk factors, including hemodialysis vintage and serum phosphorus levels, on clinical outcomes after endovascular therapy (EVT) in hemodialysis patients with CLTI. METHODS: The current study rerospectively analyzed 374 hemodialysis patients with CLTI presenting with ischemic tissue loss (age: 72.3±9.0 years, male: 73.3%, diabetes mellitus: 68.2%, Rutherford 5: 75.9%, 6: 24.1%, WIfI stage 4: 50.0%) primarily treated with EVT between April 2007 and December 2016. The primary outcome measure was 1-year amputation-free survival (AFS), while the secondary outcome measure was 1-year wound healing. Predictors for each outcome were evaluated by Cox proportional hazards model. RESULTS: Multivariate analysis significantly associated longer hemodialysis vintages with higher serum phosphorus levels (hazard ratio [HR], 0.599; 95% confidence interval [CI], 0.394-0.910; p=0.016) with 1-year AFS. Longer vintages for hemodialysis with higher serum phosphorus levels were marginally, but not significantly, associated with 1-year wound healing. (HR, 0.684; 95% CI, 0.467-1.000; p=0.050). CONCLUSION: Longer hemodialysis vintages with higher serum phosphorus levels adversely affect outcomes after EVT for hemodialysis patients with CLTI presenting with ischemic tissue loss.

Low-Voltage-Area Ablation in Paroxysmal Atrial Fibrillation　- Extended Follow-up Results of the VOLCANO Trial.

BACKGROUND: The randomized controlled VOLCANO trial demonstrated comparable 1-year rhythm outcomes between patients with and without ablation targeting low-voltage areas (LVAs) in addition to pulmonary vein isolation among paroxysmal atrial fibrillation (PAF) patients with LVAsMethods and Results:An extended-follow-up study of 402 patients enrolled in the VOLCANO trial with PAF, divided into 4 groups based on the results of voltage mapping: group A, no LVA (n=336); group B, LVA ablation (n=30); group C, LVA without ablation (n=32); and group D, incomplete voltage map (n=4). At 25 (23, 31) months after the initial ablation, AF/atrial tachycardia (AT) recurrence rates were 19% in group A, 57% in group B, 59% in group C, and 100% in group D. Recurrence rates were higher in patients with LVAs than in those without (group A vs. B+C, P<0.0001), and were comparable between those with and without LVA ablation (group B vs. C, P=0.83). Among patients who underwent repeat ablation, ATs were more frequently observed in patients with LVAs (Group B+C, 50% vs. A, 14%, P<0.0001). In addition, LVA ablation increased the incidence of AT development (group B, 71% vs. C, 32%, P<0.0001). CONCLUSIONS: Patients with LVAs demonstrated poor long-term rhythm outcomes irrespective of LVA ablation. ATs were frequently observed in patients with LVAs, and LVA ablation might exacerbate the occurrence of iatrogenic ATs.

Left Atrial Localized Low-Voltage Areas Indicate Whole Left Atrial Electrophysiological Degeneration in Atrial Fibrillation Patients.

BACKGROUND: The efficacy of ablation targeting low-voltage areas (LVAs) is controversial, although LVA presence is well known to be associated with atrial fibrillation (AF) recurrence after ablation. AF substrate may not localize within LVAs.Methods and Results:This observational study enrolled 405 consecutive patients who underwent an initial AF ablation procedure. The left atrial (LA) voltage map was obtained after pulmonary vein isolation. LVAs were defined as areas with voltage <0.5 mV. To estimate whole LA electrophysiological degeneration, mean regional voltage at each of the 6 regions and LA total conduction velocity were measured. LVAs existed in 143 of 405 (35.3%) patients. Patients with LVAs demonstrated lower mean regional voltages throughout all 6 regions compared to those without LVAs (1.3 [1.8, 0.8] vs. 0.6 [1.0, 0.2] mV for the anterior wall, P<0.001). In contrast, LA conduction velocity was lower in patients with LVAs than in those without (0.89 [1.01, 0.74] vs. 0.93 [1.03, 0.87] m/s, P<0.001). Multivariate analysis revealed that low LA total conduction velocity and a higher number of regions with mean voltage reduction were independently associated with AF recurrence, although LVA presence was not. CONCLUSIONS: Patients with localized LA LVAs were characterized by whole LA electrophysiological degeneration as assessed by mean regional voltage and conduction velocity. In addition, whole LA electrophysiological degeneration parameters were well associated with AF recurrence.

A new clinical risk score for predicting the prevalence of low-voltage areas in patients undergoing atrial fibrillation ablation.

INTRODUCTION: Although the presence of left atrial low-voltage areas (LVAs) is strongly associated with the recurrence of atrial fibrillation (AF) after ablation, few methods are available to classify the prevalence of LVAs. The purpose of this study was to establish a risk score for predicting the prevalence of LVAs in patients undergoing ablation for AF. METHODS: We enrolled 1004 consecutive patients who underwent initial ablation for AF (age, 68 ± 10 years old; female, 346 (34%); persistent AF, 513 (51%)). LVAs were deemed present when the voltage map after pulmonary vein isolation demonstrated low-voltage areas with a peak-to-peak bipolar voltage of <0.5 mV covering ≥5 cm2 of the left atrium. RESULTS: LVAs were present in 206 (21%) patients. The SPEED score was obtained as the total number of independent predictors as identified on multivariate analysis, namely female sex (odds ratio [OR], 3.4 [95% confidence interval {CI} 2.2-5.2], p < .01), persistent AF (OR, 1.8 [95% CI, 1.1-3.0], p = .02), age ≥ 70 years (OR, 2.3 [95% CI, 1.5-3.4], p < .01), elevated brain natriuretic peptide ≥100 pg/ml or N-terminal probrain natriuretic peptide ≥400 pg/ml (OR, 1.7 [95% CI, 1.02-2.8], p = .04), and diabetes mellitus (OR, 1.8 [95% CI, 1.1-2.8], p = .02). LVAs were more frequent in patients with a higher SPEED score, and prevalence increased with each additional SPEED score point (OR, 2.4 [95% CI, 2.0-2.8], p < .01). CONCLUSION: The SPEED score accurately predicts the prevalence of LVAs in patients undergoing ablation for AF.

Additional Low-Voltage-Area Ablation in Patients With Paroxysmal Atrial Fibrillation: Results of the Randomized Controlled VOLCANO Trial.

Background The efficacy of low-voltage-area (LVA) ablation has not been well determined. This study aimed to investigate the efficacy of LVA ablation in addition to pulmonary vein isolation on rhythm outcomes in patients with paroxysmal atrial fibrillation (AF). Methods and Results VOLCANO (Catheter Ablation Targeting Low-Voltage Areas After Pulmonary Vein Isolation in Paroxysmal Atrial Fibrillation Patients) trial included paroxysmal AF patients undergoing initial AF ablation. Of 398 patients in whom a left atrial voltage map was obtained after pulmonary vein isolation, 336 (85%) had no LVA (group A). The remaining 62 (15%) patients with LVAs were randomly allocated to undergo LVA ablation (group B, n=30) or not (group C, n=32) in a 1:1 fashion. Primary end point was 1-year AF-recurrence-free survival rate. No adverse events related to LVA ablation occurred. Procedural (124±40 versus 95±33 minutes, P=0.003) and fluoroscopic times (29±11 versus 24±8 minutes, P=0.034) were longer in group B than group C. Patients with LVAs demonstrated lower AF-recurrence-free survival rates (88%) than those without LVA (B, 57%, P<0.0001; C, 53%, P<0.0001). However, LVA ablation in addition to pulmonary vein isolation did not impact AF-recurrence-free survival rate (group B versus C, P=0.67). Conclusions The presence of LVA was a strong predictor of AF recurrence after pulmonary vein isolation in patients with paroxysmal AF. However, LVA ablation had no beneficial impact on 1-year rhythm outcomes. Registration URL: https://www.umin.ac.jp/ctr; Unique identifier: UMIN000023403.

Left atrial voltage mapping with a direction-independent grid catheter: Comparison with a conventional circular mapping catheter.

INTRODUCTION: A recently introduced grid mapping catheter (GMC) is designed for better electrode-tissue contact and can collect bipolar signals both along and across the splines, which may allow more efficient voltage map generation independent of propagation direction. We compared the GMC with a conventional circular mapping catheter (CMC) for left atrial (LA) voltage mapping. METHODS: This study included 20 consecutive patients undergoing repeat ablation for recurrent atrial fibrillation who had demonstrated LA low-voltage areas (LVAs, <0.10 mV). Following pulmonary vein isolation, LA voltage mapping was performed twice, once using the GMC and once using the CMC. RESULTS: Voltage mapping was more efficient using the GMC than the CMC in terms of mapping time (459 [404, 543] vs 602 [496, 814] seconds; P = .014) and the number of mapping points (2446 [2099, 3104] vs 1841 [1494, 2314]; P = .002). The incidence of catheter-induced ectopies was lower (44 [28, 62] vs 114 [74, 188]; P < .0001) using the GMC. The GMC utilizing all bipoles detected LVAs in 85% of patients with LVAs detected by CMC. LVA measurements were significantly smaller on maps generated by the GMC using bipoles along or across the splines than those measured with the CMC (11.1 [4.6, 17.2] or 9.7 [2.5, 16.0] vs 16.4 [6.8, 26.8] cm2 ; P = .008 and P = .001, respectively), and were even smaller when using all bipoles (7.9 [1.1, 13.5] cm2 , P = .0001). CONCLUSION: The GMC allowed a more efficient mapping procedure and enabled more selective identification of LVAs with smaller LVA size.

Centrifugal Wave Front Propagation Speed for Localizing the Origin of Ventricular Arrhythmias: Investigation Using a New Ultra-High-Resolution Mapping System.

OBJECTIVES: The aim of this study was to assess the use of wave front propagation speed on a right ventricular map for determining the earliest activation site as the origin of outflow tract ventricular arrhythmias (VAs). BACKGROUND: VAs with centrifugal right ventricular outflow tract (RVOT) activation can be from an RVOT focus or a focus outside the RVOT. METHODS: This prospective observational study included 23 patients with idiopathic outflow tract VAs. Mapping of the RVOT was performed using a new ultra-high-resolution electroanatomic mapping system. The wave front propagation speed was estimated from the area surrounded by a propagated wave front at 5, 10, 15, and 20 ms after the earliest activation. RESULTS: VAs disappeared following ablations in the RVOT in 15 patients (RVOT origin). The remaining 8 patients had VAs of non-RVOT origin determined by ablation success at another site or ablation failure. The areas surrounded by a propagated wave front were significantly smaller in VAs of RVOT origin than non-RVOT VAs at 5 ms (1.0 [0.7 to 1.1] cm2 vs. 2.2 [1.6 to 4.4] cm2), 10 ms (1.9 [1.4 to 2.2] cm2 vs. 4.5 [3.2 to 5.8] cm2), 15 ms (3.2 [2.3 to 4.4] cm2 vs. 7.1 [6.3 to 9.8] cm2), and 20 ms (5.0 [3.0 to 6.6] cm2 vs. 9.8 [9.3 to 14.8] cm2). A propagated area of <5.0 cm2 at 15 ms predicted RVOT VAs with 87% sensitivity, 100% specificity, and 91% predictive accuracy. CONCLUSIONS: VAs with slow wave front propagation speed on the right ventricular map indicate an RVOT origin.

Comparison of Left Atrial Voltage between Sinus Rhythm and Atrial Fibrillation in Association with Electrogram Waveform.

BACKGROUND: The efficacy of low-voltage-guided ablation in addition to pulmonary vein (PV) isolation for atrial fibrillation (AF) has been reported with voltage mapping being performed during sinus rhythm (SR) or AF. The study aimed to compare the left atrial voltage between SR and AF in association with the electrogram waveform. METHODS: This prospective observational study included 30 consecutive patients with persistent AF. After completion of PV isolation, electrogram points were taken during both SR and AF at the identical locations evenly throughout the left atrium. Electrograms were divided into two types: normal (sharp electrogram with ≤3 peaks or duration <50 ms) and fractionated (>3 peaks and duration ≥50 ms). RESULTS: During SR, 14 (47%) patients had low-voltage (0.5 mV) substrate with an area of 6.8 ± 4.5 cm2 . In a total of 1,063 point pairs, 135 (13%) demonstrated a fractionated electrogram during SR and 483 (45%) during AF. The locations with fractionated electrograms during AF more frequently showed fractionation during SR compared to those with normal electrograms during AF (23% vs 5%, P < 0.0001), and had lower amplitude during SR (1.47 ± 1.29 mV vs 2.03 ± 1.19 mV, P < 0.0001). Electrogram amplitude was higher during SR than that during AF (1.77 ± 1.27 mV vs 0.96 ± 0.77 mV, P < 0.0001) with a weak correlation (r = 0.56, P < 0.0001). Subgroup analyses revealed that the correlation was relatively strong (r = 0.73, P < 0.0001) among the electrogram amplitudes with normal waveform during SR and AF. CONCLUSIONS: Significant differences in electrogram voltage and fractionation degree may exist between SR and AF at the same locations in patients with persistent AF.