67 research outputs found
Voxel based adaptive meshless method for cardiac electrophysiology simulation
No full textIn this paper, an adaptive meshless method is described for solving the modified FitzHugh Nagumo equations on a set of nodes directly imported from the voxels of the medical images. The non-trivial task of constructing suitable meshes for complex geometries to solve the reaction-diffusion equations is circumvented by a meshfree implementation. The spatial derivatives arising in the reaction diffusion system are estimated using the Lagrangian form of scattered node radial basis function interpolant. Normal cardiac activation phenomena is fast, with a very steep upstroke and localised as compared to the size of the computational domain. To accurately capture this phenomena, a space adaptive method is presented where extra nodes are placed near the region of the activation front. The performance of the adaptive method is investigated first for synthetic geometry and then applied to a real-life geometry obtained from magnetic resonance imaging. Numerical results suggest that the presented method is capable of predicting realistic electrophysiology simulation effectivel
Posterior Wall Isolation Improves Outcomes for Persistent AF With Rapid Posterior Wall Activity: A CAPLA Substudy
No full textAbstract not availableLouise Segan, David Chieng, Sandeep Prabhu, Andrew Hunt, Troy Watts, Brian Klys, Aleksandr Voskoboinik, Hariharan Sugumar, Liang-Han Ling, Geoff Lee, Joseph Morton, Rajeev K. Pathak, Deep Chandh Raja, Laurence Sterns, Matthew Ginks, Prashanthan Sanders, Jonathan M. Kalman, Peter M. Kistle
Role of impedance drop and lesion size index (LSI) to guide catheter ablation for atrial fibrillation
No full textBackground
When using lesion size index (LSI) to guide catheter ablation, it is unclear what combination of power, contact force and time would be preferable to use and what LSI target value to aim for. This study aimed at identifying desirable ablation settings and LSI targets by using tissue impedance drop as indicator of lesion formation.
Methods
Consecutive patients, undergoing their first left atrial (LA) catheter ablation for atrial fibrillation, with radiofrequency energy (RF) powers of 20, 30 and 40 W were enrolled. Tissue impedance, contact force (CF), Force Time Integral (FTI) and LSI values were continuously recorded during ablation and sampled at 100 Hz. Mean CF and Contact Force Variability (CFV) were calculated for every lesion. The effect of RF power, ablation time, CF and CFV on impedance drop and LSI were assessed.
Results
A total of 3258 lesions were included in the analysis. For any target LSI value, use of higher RF powers translated into progressively higher impedance drops. The impact of lower CF and higher CFV on impedance drop was more relevant when using lower powers. Target LSI values corresponding to maximum impedance drop were identified depending on RF power, mean CF and CFV used.
Conclusions
Even in the context of an LSI-guided ablation strategy, use of lower or higher powers might lead to different lesion sizes. Different LSI targets might be needed depending on the combination of RF power, CF and CFV used for ablation. Incorporating indicators of catheter stability, like CFV, in the LSI formula could improve the predictive value of LSI for lesion size. Studies with clinical outcomes are required to confirm the clinical relevance of these findings
INtra-procedural ultraSound Imaging for DEtermination of atrial wall thickness and acute tissue changes after isolation of the pulmonary veins with radiofrequency, cryoballoon or laser balloon energy: the INSIDE PVs study
No full textPreliminary data in human suggest that both Intracardiac echocardiography (ICE) and Intravascular ultrasound (IVUS) can be used for real-time information on the left atrial (LA) wall thickness and on the acute tissue changes produced by energy delivery. This pilot study was conducted to compare ICE and IVUS for real-time LA wall imaging and assessment of acute tissue changes produced by radiofrequency (RF), cryo and laser catheter ablation. Patients scheduled for RF, cryoballoon or laser balloon Pulmonary Vein Isolation (PVI) catheter ablation were enrolled. Each pulmonary vein (PV) was imaged before and immediately after ablation with either ICE or IVUS. The performance of ICE and IVUS for imaging were compared. Pre- and post-ablation measurements (lumen and vessel diameters, areas and sphericity indexes, wall thickness and muscular sleeve thickness) were taken at the level of each PV ostium. A total of 48 PVs in 12 patients were imaged before and after ablation. Both ICE and IVUS showed acute tissue changes. Compared to IVUS, ICE showed higher imaging quality and inter-observer reproducibility of the PV measurements obtained. Acute wall thickening suggestive of oedema was observed after RF treatment (p = 0.003) and laser treatment (p = 0.003) but not after cryoablation (p = 0.69). Our pilot study suggests that ICE might be preferable to IVUS for LA wall thickness imaging at the LA-PV junctions during ablation. Ablation causes acute wall thickening when using RF or laser energy, but not cryoenergy delivery. Larger studies are needed to confirm these preliminary findings
Incidence, characteristics, and prognostic significance of early recurrences after different ablation approaches for persistent atrial fibrillation
No full textPublished November 2025BACKGROUND Early recurrence of atrial tachyarrhythmia (ERAT) is common after catheter ablation of atrial fibrillation (AF). The specific clinical and arrhythmia characteristics of ERAT influencing late recurrence risk in persistent AF are unclear. In addition, the impact of different ablation strategies on the incidence and prognostic significance of ERAT remains unknown. OBJECTIVE This study aimed to assess the incidence, characteristics, and prognostic impact of ERAT in patients with persistent AF undergoing pulmonary vein isolation alone or pulmonary vein isolation with posterior wall isolation. METHODS Trial participants monitored by implantable cardiac devices or twice-daily electrocardiogram transmissions were included. Atrial arrhythmia recurrences lasting ≥ 30 seconds were classified as ERAT (within 3 months after ablation) or late recurrence (between 3 and 12 months). RESULTS Of the 282 included patients, ERAT occurred in 124 (44.0%). ERAT portended an increased incidence of late recurrence (68.5% vs 32.9%; hazard ratio, 3.36; 95% confidence interval, 2.35–4.79) and significantly higher post–blanking period AF burden (median, 0.66% [interquartile range, 0–8.35%] vs 0% [0–0.55%]). The hazard ratio for late recurrence was 2.34 (1.48–3.71), 2.89 (1.63–5.12), and 6.00 (3.86–9.32) when the latest ERAT occurred in the first, second, and third month, respectively. Late recurrence risk was particularly elevated in patients with high-burden, frequent, or symptomatic ERAT. Ablation strategy did not affect the incidence, burden, arrhythmia characteristics, or prognostic significance of ERAT. CONCLUSION ERAT after radiofrequency ablation of persistent AF is an independent predictor of late recurrence and increased post–blanking period AF burden. An individualized assessment of early recurrences is warranted to critically evaluate their clinical significance.Sohaib A. Virk, David Chieng, Louise Segan, Joseph B. Morton, Geoffrey Lee, Paul Sparks, Alex J. McLellan, Hariharan Sugumar, Sandeep Prabhu, Liang-Han Ling, Aleksandr Voskoboinik, Rajeev K. Pathak, Laurence D. Sterns, Matthew Ginks, Prashanthan Sanders, Peter Kistler, Jonathan Kalma
Impact of Posterior Left Atrial Voltage on Ablation Outcomes in Persistent Atrial Fibrillation: CAPLA Substudy
No full textBACKGROUND Pulmonary vein isolation (PVI) is less effective in patients with persistent atrial fibrillation (PsAF). Adjunctive ablation targeting low voltage areas (LVAs) may improve arrhythmia outcomes. OBJECTIVES This study aims to compare the outcomes of adding posterior wall isolation (PWI) to PVI, vs PVI alone in PsAF patients with posterior wall LVAs. METHODS The CAPLA (Effect of Catheter Ablation Using Pulmonary Vein Isolation With vs Without Posterior Left Atrial Wall Isolation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation) study was a multicenter, randomized trial involving PsAF patients randomized 1:1 to either PVI alone or PVI with PWI. Voltage mapping performed during pacing pre-ablation was reviewed offline, with LVA defined as bipolar voltage of 30 seconds off antiarrhythmic medication at 12 months after a single ablation procedure in patients with posterior LVA. RESULTS A total of 210 patients (average 64.6 ± 9.2 years,73.3% males, median atrial fibrillation duration 4.5 months [IQR: 2 to 8 months]) underwent multipolar left atrial mapping during coronary sinus pacing with posterior LVA present in 69 (32.9%). Patients with posterior LVA were more likely to have LVA in other atrial regions (91.7% vs 57.1%; P < 0.01), larger left atrial diameter (4.8 cm vs 4.4 cm; P < 0.01), and significantly increased risk of atrial arrhythmia recurrence at 12 months (LVA: 56.5% vs no LVA: 41.4%; HR: 1.51; 95% CI: 1.01-2.27; P 1/4 0.04) compared to no posterior LVA. However, the addition of PWI to PVI did not significantly improve freedom from atrial arrhythmia recurrence over PVI alone (PVI with PWI: 44.8% vs PVI: 41.9%; HR: 0.95; 95% CI: 0.51-1.79; P = 0.95). CONCLUSIONS In patients with PsAF undergoing catheter ablation, posterior LVA was associated with a significant increase in atrial arrhythmia recurrence. However, the addition of PWI in those with posterior LVA did not reduce atrial arrhythmia recurrence over PVI alone.David Chieng, Hariharan Sugumar, Andrew Hunt, Liang-Han Ling, Louise Segan, Ahmed Al-Kaisey, Joshua Hawson, Sandeep Prabhu, Aleksandr Voskoboinik, Geoffrey Wong, Joseph B. Morton, Geoffrey Lee, Matthew Ginks, Laurence Sterns, Prashanthan Sanders, Jonathan M. Kalman, Peter M. Kistle
Persistent Atrial Fibrillation Phenotypes and Ablation Outcomes: Persistent From Outset vs Progression From Paroxysmal AF
No full textAvailable online 27 September 2024BACKGROUND: Many patients with persistent atrial fibrillation (PsAF) have progressed from an initial paroxysmal phenotype; however, there are patients in whom atrial fibrillation (AF) is persistent at diagnosis. Relatively little is known about this subgroup, but prior observational studies have suggested these patients have worse outcomes with ablation. OBJECTIVES: This study sought to: 1) assess demographic and electrophysiologic characteristics of patients with PsAF at first diagnosis compared with those with who have progressed from paroxysmal atrial fibrillation (PAF); and 2) assess the impact of pattern of AF at diagnosis on recurrence post ablation. METHODS: CAPLA (Catheter Ablation for persistent atrial fibrillation: A Multicentre randomised trial of Pulmonary vein isolation [PVI] vs PVI with posterior Left Atrial wall isolation [PWI]) was a multicenter trial that randomized patients with PsAF to PVI plus PWI or PVI alone. Follow-up was 12 months. Outcomes were assessed after a 3-month blanking period. RESULTS: A total of 334 patients were included (median age 65.6 years, 23.1% female), 194 (58.1%) had PsAF at first AF diagnosis and 140 (41.9%) had PAF. Patients with PsAF at diagnosis were younger (age 64.0 vs 67.7 years, P = 0.005), had higher rates of heart failure (P < 0.001), and lower left ventricular ejection fraction (54.5% IQR: 40-60 vs 60% IQR: 50-61, P = 0.007). AF recurrence occurred in 85 (43.8%) with PsAF at diagnosis and 70 (50%) with PAF at diagnosis. PsAF at diagnosis was not associated with risk of recurrence on univariable (HR: 0.802; 95% CI: 0.585-1.101; P = 0.173) or multivariable analysis (HR: 0.922; 95% CI: 0.647-1.312; P = 0.650). Median AF burden was 0% in both groups (P = 0.125). There was no difference in left atrial size (P = 0.337) or bipolar voltage (P = 0.579) between the groups. CONCLUSIONS: In the CAPLA cohort of patients, pattern of AF at first diagnosis did not influence post-ablation rate of AF recurrence or AF burden. (Catheter Ablation for persistent atrial fibrillation: A Multicentre randomised trial of Pulmonary vein isolation [PVI] vs PVI with posterior Left Atrial wall isolation [PWI]; ACTRN12616001436460).Rose Crowley, David Chieng, Louise Segan, Jeremy William, Hariharan Sugumar, Sandeep Prabhu, Aleksandr Voskoboinik, MBBS, Liang-Han Ling, Joseph B. Morton, f Geoffrey Lee, Alex J. McLellan, Michael Wong, Rajeev K. Pathak, Laurence Sterns, Matthew Ginks, Prashanthan Sanders, Peter M. Kistler, Jonathan M. Kalma
Sex specific outcomes following catheter ablation in persistent AF
No full textAvailable online 8 February 2024BACKGROUND Sex-specific outcomes after catheter ablation (CA) for atrial fibrillation (AF) have reported conflicting findings. OBJECTIVE We examined the impact of female sex on outcomes in patients with persistent AF (PsAF) from the Catheter Ablation for Persistent Atrial Fibrillation: A Multicentre Randomized Trial of Pulmonary Vein Isolation vs PVI with Posterior Left Atrial Wall Isolation (CAPLA) randomized trial. METHODS A total of 338 patients with PsAF were randomized to pulmonary vein isolation (PVI) or PVI with posterior wall isolation (PWI). The primary outcome was arrhythmia recurrence at 12 months. Clinical and electroanatomical characteristics, arrhythmia recurrence, and quality of life were compared between women and men. RESULTS Seventy-ninewomen (23.4%; PVI 37; PVI1PWI 42) and 259 men (76.6%; PVI 131; PVI1PWI 128) underwent AF ablation. Womenwere older {median age 70.4 (interquartile range [IQR] 64.8–74.6) years vs 64.0 (IQR 56.7–69.7) years; P < .001} and had more advanced left atrial electroanatomical remodeling. At 12 months, arrhythmia-free survival was lower in women (44.3% vs 56.8% in men; hazard ratio 1.44; 95% confidence interval 1.02–2.04; log-rank, P 5 .036). PWI did not improve arrhythmia-free survival at 12 months (hazard ratio 1.02; 95% confidence interval 0.74–1.40; log-rank, P 5 .711). The median AF burden was 0% in both groups (women: IQR 0.0%–2.2% vs men: IQR 0.0%–2.8%; P 5 .804). Health care utilization was comparable between women (36.7%) and men (30.1%) (P 5 .241); however, women were more likely to undergo a repeat procedure (17.7% vs 6.9%; P 5 .007). Women reported more severe baseline anxiety (average Hospital Anxiety and Depression Scale [HADS] anxiety score 7.5 6 4.9 vs 6.3 6 4.3 in men; P 5 .035) and AF-related symptoms (baseline Atrial Fibrillation Effect on Quality-of-Life Questionnaire [AFEQT] score 46.7 6 20.7 vs 55.96 23.0 inmen; P5 .002), with comparable improvements in psychological symptoms (change in HADS anxiety score 23.864.6 vs23.064.5; P5.152 (change inHADS depression score22.965.0 vs22.664.0; P5.542) and greater improvement in AFEQT score compared with men at 12 months (change in AFEQT score 145.9 6 23.1 vs 139.2 6 24.8; P 5 .048). CONCLUSION Women undergoing CA for PsAF report more significant symptoms and poorer quality of life at baseline than men. Despite higher arrhythmia recurrence and repeat procedures in women, the AF burden was comparably low, resulting in significant improvements in quality of life and psychological well-being after CA in both sexes.Louise Segan, David Chieng, Rose Crowley, Jeremy William, Hariharan Sugumar, Liang-Han Ling, Joshua Hawson, Sandeep Prabhu, Aleksandr Voskoboinik, M Joseph B. Morton, Geoffrey Lee, Laurence D. Sterns, Matthew Ginks, Prashanthan Sanders, Jonathan M. Kalman, Peter M. Kistle
115 Quality of conflicts of interest declarations in a conference setting – are audiences given a chance to adequately assess bias?
No full textAn MRI/CT-based cardiac electroanatomical mapping system with scattered data interpolation algorithm
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