Cost, Efficiency and Outcomes of Pulsed Field Ablation versus Thermal Ablation for Atrial Fibrillation: A Real World Study.

BACKGROUND: With the exponential growth of catheter ablation (CA) for atrial fibrillation (AF), there is increasing interest in associated healthcare costs. Pulsed field ablation (PFA) using a single-shot pentaspline multi-electrode catheter has been shown to be safe and effective for AF CA, but its cost efficiency compared to conventional thermal ablation modalities (cryoballoon [CB] or radiofrequency [RF]) has not been evaluated. OBJECTIVE: To compare cost, efficiency, effectiveness and safety between PFA, CB and RF for AF ablation. METHODS: We studied 707 consecutive patients (208 PFA, 325 CB, 174 RF) undergoing first-time AF ablation. Individual procedural costs were calculated, including equipment, lab utilisation and hospital stay, and compared between ablation modalities, as effectiveness and safety. RESULTS: Skin-to-skin times and catheter lab times were significantly shorter with PFA (68min/102min) vs CB (91min/122min) and RF (89min/123 min); p<0.001. General anaesthesia utilisation differed across modalities (PFA 100%, CB 10.2%, RF 61.5%); p<0.001. Major complications occurred in 1% of cases, with no significant differences between modalities. Shorter procedural times resulted in lower staffing and lab costs with PFA, but these savings were offset by substantially higher equipment costs, resulting in higher overall median costs with PFA (£10,010) vs CB (£8,106) and RF (£8,949); p<0.001. CONCLUSION: In this contemporary real-world study of the three major AF CA modalities used concurrently, PFA had shorter skin-to-skin and catheter lab times than CB and RF, with similarly low rates of complications. However, PFA procedures were considerably more expensive, largely due to higher equipment cost.

Durability of Thermal Pulmonary Vein Isolation in Persistent Atrial Fibrillation Assessed by Mandated Repeat Invasive Study.

BACKGROUND: No study has assessed durability of pulmonary vein isolation (PVI) with radiofrequency (RF) and Cryoballoon (CB) in patients with persistent AF. These data are especially lacking for those with significantly diseased left atria (LA). OBJECTIVE: To assess PVI durability in patients with significant LA disease and compare reconnection rates between RF and CB. METHODS: 44 Patients (mean age 63, 77% male, median time since AF diagnosis 22.5 months, median indexed LA volume 36 ml/m2) were randomised 1:1 to RF (StablePoint catheter, Boston Scientific) or CB (Arctic Front Advance, Medtronic) PVI. A redo procedure using ultra high-density electroanatomic mapping (Rhythmia, Boston Scientific) was mandated at 2 months, where PV reconnections were identified and re-isolated. RESULTS: 38 patients underwent both procedures (n=17 CB, n=21 RF). Index RF procedures were longer (median 158 vs 97min; p<0.001) but required less fluoroscopy (9.5 vs 23min; p<0.001). At the index RF procedure, median 47% of LA myocardium had voltage <0.5mV, suggesting half of the mapped LA comprised scar. PV reconnection was observed in 73/152 (48.0%) PVs and was more frequent with CB (58.8%) vs RF (39.3%), p=0.022. Reconnection of at least 1 PV was detected in >75% of patients. Significantly more ablation was required at redo to reisolate PVs in the CB arm (median 10.8 vs 1.2min; p<0.001). CONCLUSION: PVI durability may be poor in those with significant LA scarring and dilatation, even with modern thermal ablation technologies. RF resulted in significantly better PVI durability than CB in this complex population. CLINICAL TRIAL REGISTRATION: NCT04111731.

Lesion metrics and 12-month outcomes of very-high power short duration radiofrequency ablation (90W/4 s) under mild conscious sedation.

INTRODUCTION: Pulmonary vein isolation (PVI) is often performed under general anaesthesia (GA) or deep sedation. Anaesthetic availability is limited in many centers, and deep sedation is prohibited in some countries without anaesthetic support. Very high-power short duration (vHPSD-90W/4 s) PVI using the Q-Dot catheter is generally well tolerated under mild conscious sedation (MCS) though an understanding of catheter stability and long-term effectiveness is lacking. We analyzed lesion metrics and 12-month freedom from atrial arrythmia with this approach. METHODS: Our approach to radiofrequency (RF) PVI under MCS is standardized and includes a single catheter approach with a steerable sheath. We identified patients undergoing Q-Dot RF PVI between March 2021 and December 2022 in our center, comparing those undergoing vHPSD ablation under MCS (90W/MCS) against those undergoing 50 W ablation under GA (50 W/GA) up to 12 months of follow-up. Data were extracted from clinical records and the CARTO system. RESULTS: Eighty-three patients met our inclusion criteria (51 90W/MCS; 32 50 W/GA). Despite shorter ablation times (353 vs. 886 s; p < .001), the 90 W/MCS group received more lesions (median 87 vs. 58, p < .001), resulting in similar procedure times (149.3 vs. 149.1 min; p = .981). PVI was achieved in all cases, and first pass isolation rates were similar (left wide antral circumferential ablation [WACA] 82.4% vs. 87.5%, p = .758; right WACA 74.5% vs. 78.1%, p = .796; 90 W/MCS vs. 50 W/GA respectively). Analysis of 6647 ablation lesions found similar mean impedance drops (10.0 ± 1.9 Ω vs. 10.0 ± 2.2 Ω; p = .989) and mean contact force (14.6 ± 2.0 g vs. 15.1 ± 1.6 g; p = .248). Only median 2.5% of lesions in the 90 W/MCS cohort failed to achieve ≥ 5 Ω drop. In the 90 W/MCS group, there were no procedural related complications, and 12-month freedom from atrial arrhythmia was observed in 78.4%. CONCLUSION: vHPSD PVI is feasible under MCS, with encouraging acute and long-term procedural outcomes. This provides a compelling option for centers with limited anaesthetic support.

Relationship of Warfarin and Apixaban with Vascular Function in Patients with Atrial Fibrillation.

INTRODUCTION: Atrial fibrillation (AF) is associated with endothelial damage/dysfunction. Herein, we tested the hypothesis that brachial artery flow-mediated dilation (FMD) is superior in AF patients taking apixaban compared to warfarin. METHODS: AF patients on apixaban (n = 46; 67 [7] years; mean [standard deviation]; 15 women) and warfarin (n = 27; 73 [9] years (p < 0.01); 11 women) were recruited. Duplex Doppler ultrasound imaging was undertaken during baseline (2 min), cuff inflation (5 min), and following cuff deflation (3 min). FMD was defined as peak increase in brachial artery diameter following cuff deflation and analysed as percentage change in diameter, as a ratio of FMD, shear rate area under the curve (SRAUC; FMD-to-SRAUC), and using SRAUC as a covariate (FMDSR). RESULTS: Baseline artery diameter (4.96 [1.14] vs. 4.89 [0.88] mm), peak diameter (5.12 [1.17] vs. 5.14 [0.93] mm), and FMDSR (3.89 [3.62] vs. 4.80 [3.60] %) were not different between warfarin and apixaban (p > 0.05; analysis of covariance with age, CHA2DS2-VASc, years since AF diagnosis, number of diabetics, alcohol drinkers, and units of alcohol consumed per week as covariates). Stepwise multiple regression identified independent association of fibrillation, hypertension, and increased age with FMD. CONCLUSION: AF patients on warfarin and apixaban exhibit similar endothelium-dependent vasodilation. Increased blood pressure negatively impacts vasodilator capacity in AF patients.

Silent pulmonary veins at redo ablation for atrial fibrillation: Implications and approaches.

BACKGROUND: Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. Despite promising success rates, redo ablation is sometimes required. At redo, PVs may be found to be isolated (silent) or reconnected. We studied patients with silent vs reconnected PVs at redo and analysed associations with adverse outcomes. METHODS: Patients undergoing redo AF ablations between 2013 and 2019 at our institution were included and stratified into silent PVs or reconnected PVs. The primary outcome was a composite of further redo ablation, non-AF ablation, atrioventricular nodal ablation, and death. Secondary outcomes included arrhythmia recurrence. RESULTS: A total of 467 patients were included with mean 4.6 ± 1.7 years follow-up, of whom 48 (10.3%) had silent PVs. The silent PV group had had more often undergone >1 prior ablation (45.8% vs 9.8%; p<0.001), had more persistent AF (62.5% vs 41.1%; p=0.005) and had more non-PV ablation performed both at prior ablation procedures and at the analysed redo ablation. The primary outcome occurred more frequently in those with silent PVs (25% vs 13.8%; p=0.053). Arrhythmia recurrence was also more common in the silent PV group (66.7% vs 50.6%; p=0.047). After multivariable adjustment, female sex (aHR 2.35 [95% CI 2.35-3.96]; p=0.001) and ischaemic heart disease (aHR 3.21 [95% CI 1.56-6.62]; p=0.002) were independently associated with the primary outcome, and left atrial enlargement (aHR 1.58 [95% CI 1.20-2.08]; p=0.001) and >1 prior ablation (aHR 1.88 [95% CI 1.30-2.72]; p<0.001) were independently associated with arrhythmia recurrence. Whilst a finding of silent PVs was not itself significant after multivariable adjustment, this provides an easily assessable parameter at clinically indicated redo ablation which informs the clinician of the likelihood of a worse future prognosis. CONCLUSIONS: Patients with silent PVs at redo AF ablation have worse clinical outcomes.

Incidence of vascular complications for electrophysiology procedures in the ultrasound era: a single-centre experience over 10,000 procedures in the long term.

BACKGROUND: Ultrasound (US) is being increasingly used to guide vascular access for electrophysiology (EP) procedures in many centres. Nonetheless, the incidence and predictors of vascular complications in the US era are limited. In this study, we describe our experience of vascular access-related complications associated with EP procedures which were performed with the routine use of US-guided vascular access. METHODS: A total of 10,158 consecutive EP procedures in 8361 patients performed from April 2014 (when our centre moved to a policy of routine US-guided vascular access for EP procedures) to March 2022 were included. The outcome of interest was any vascular access-related complication that occurred within 7 days of the procedure; these were classified as severe if surgical intervention and/or blood transfusion was required, major if non-surgical intervention or delayed hospital discharge was required, or minor if it did not fulfil the criteria for severe or major. RESULTS: During the study period, 2 (0.02%) severe vascular complications occurred, including 1 pseudo-aneurysm requiring surgery and 1 retroperitoneal haemorrhage requiring blood transfusion. Nine (0.09%) major complications occurred, including 6 hematomas managed by compression devices, 1 type B aortic dissection, 1 AV fistula managed conservatively and 1 haematoma managed conservatively but delayed hospital discharge. Eighteen (0.18%) minor haematomas were seen that did not require any intervention or delayed hospital discharge. On multivariable analysis, female sex [OR (95% CI): 2.5 (1.2, 5.4)] and use of an arterial access [OR (95% CI): 19.3 (7.1, 52.3)] were seen to be independent predictors of the 29 vascular complications. CONCLUSION: With the use of US-guided vascular access in EP procedures, major vascular complications are exceedingly rare, particularly those needing surgical intervention. Our results provide additional evidence for scientific guidelines to support US use.

Patient experience of very high power short duration radiofrequency ablation for atrial fibrillation under mild conscious sedation.

BACKGROUND: Very high power short duration (vHPSD) radiofrequency ablation (RFA) may reduce ablation times and improve patient tolerability, permitting pulmonary vein isolation (PVI) under mild conscious sedation (mCS) and promoting same day discharge (SDD). METHODS: First, a retrospective feasibility study was performed at 2 tertiary cardiac centres in the UK. Consecutive cases of first-time PVI using vHPSD ablation with 90 W lesions for up to 4 s were compared against cases performed using standard RF (sRF) and cryoballoon (Cryo) therapy. Subsequently, a prospective study of patients who had vHPSD or Cryo exclusively under mCS was undertaken. Questionnaires based on Likert and visual analogue scales (VAS) were used to measure anxiety, discomfort and pain. RESULTS: In total, 182 patients (59 vHPSD, 62 sRF and 61 Cryo) were included in the retrospective study, with 53 (90%) of vHPSD cases successfully performed under mCS. PVI ablation time in the vHPSD group (5.8 ± 1.7 min) was shorter than for sRF (16.5 ± 6.3 min, p < 0.001) and Cryo (17.5 ± 5.9 min, p < 0.001). Fifty-one vHPSD and 52 Cryo patients were included in the prospective study. PVI ablation time in the vHPSD group was shorter than for the Cryo group (6.4 ± 2.9 min vs 17.9 ± 5.7 min, p < 0.001), but overall procedure duration was longer (121 ± 39 min vs 95 ± 20 min, p < 0.001). There were no differences in the patient experience of anxiety, discomfort or pain. SDD rates were the same in both groups (61% vs 67%, p = 0.49). CONCLUSIONS: vHPSD RFA for PVI can be performed under mCS to achieve SDD rates comparable to cryoablation, without compromising patient experience.

Impact of COVID-19 pandemic on cardiac rhythm management services: Views from the United Kingdom.

Background: Effects of the COVID-19 pandemic on cardiac rhythm management (CRM) services remain poorly quantified. Objective: To describe the impact of COVID-19 on specialist CRM centers in the United Kingdom (UK). Methods: Two-center study involving the Liverpool Heart and Chest Hospital NHS Foundation Trust and Royal Papworth Hospital NHS Foundation Trust. The first nationwide lockdown lasted from April to July 2020 and the second from December 2020 to March 2021. Results: Compared to the pre-pandemic period, pandemic 1 (April-July 2020) was associated with a 52.2% reduction in electrophysiology (EP) procedures (P = .083), 32.7% reduction in device procedures (P = .003), and 36.8% decrease in CRM referrals (P < .001). There was also a 13.4% increase in the use of conscious sedation (CS) (P < .001) and day-case procedures for EP (P = .003), with no change in day-case device procedures (P = .555). Corresponding numbers for pandemic 2 (August-November 2020) were a 0.7% increase in EP procedures (P = .925), 7.9% reduction in device procedures (P = .232), 13.9% decrease in referrals (P = .014), 5.5% increase in CS for EP (P = .009), 7.1% increase in day-case EP procedures (P < .001), and no change in day-case device procedures (P = .537). Corresponding numbers for pandemic 3 (December 2020-March 2021) were a 31.6% reduction in EP procedures (P = .001), 22.3% reduction in device procedures (P = .006), 8.4% decrease in referrals (P = .094), 11.0% increase in CS for EP (P < .001), 7.6% increase in day-case EP procedures (P = .003), and no change in day-case device procedures (P = .146). By the end of March 2021, the CRM waiting list was 167.8% pre-pandemic levels. Conclusion: During the COVID-19 pandemic, specialist centers in the UK were affected such that the number of procedures performed was greatly reduced in the initial period with latter improvements as better coping strategies were developed.

Ablation index-guided 50W radiofrequency ablation for left atrial posterior wall isolation in atrial fibrillation.

BACKGROUND: Ablation index (AI)-guided ablation for posterior wall isolation (PWI) using high-power, short-duration remains untested. We sought to evaluate the acute outcomes of AI-guided 50 W ablation vs. conventional ablation, and investigate the differences in relationship between contact force (CF), time and AI in both groups. METHODS: Consecutive patients undergoing first-time AI-guided ablation with PWI using either 50 W or 35-40 W ablation were enrolled. Acute procedural metrics and individual lesion level ablation data were compared between groups. RESULTS: 40 patients (50 W: n = 20, 35-40 W: n = 20) with atrial fibrillation were included. Total procedure time was significantly reduced with 50 W (120 vs. 143 mins, p = 0.004) and there was a trend toward decreased ablation time (22 vs. 28 mins, p = 0.052). First pass and acute success of PWI were comparable between the 50 W and 35-40 W groups (10 vs. 8 patients, p = 0.525 and 20 vs. 19 patients, p = 1.000, respectively). Individual lesion analysis of all 959 RF applications (50 W: n = 458, 35-40 W: n = 501) demonstrated that 50 W ablation led to lower ablation time per lesion (10.4 vs. 13.0s, p < 0.001), and increased AI (471 vs. 461, p < 0.001) and impedance drop (7.4 vs. 6.9ohms, p = 0.007). Excessive ablations (AI>600 for roof line; AI>500 elsewhere) were more frequently observed in the 50 W group (9.0% vs. 4.6%, p = 0.007). CF had very good discriminative capability for excessive ablation in both groups. At 50 W, limiting the CF to <10 g reduced the number of excessive ablations on the floor line and within the posterior box to 12% and 4%,respectively. Recurrence of atrial arrhythmias at 12 months were comparable between the groups. CONCLUSION: AI-guided 50 W RF ablation reduces the ablation time of individual lesions and total procedure time without compromising first pass and acute success rates of PWI or 12-month outcomes compared to conventional powers.

Impact of COVID-19 on patients awaiting ablation for atrial fibrillation.

OBJECTIVE: Atrial fibrillation (AF) ablation services were significantly affected by the COVID-19 pandemic. We aimed to evaluate a symptom-based clinician prioritisation scheme for waiting list management compared with patient-completed quality of life (QoL) scores. We also sought to understand factors influencing QoL, particularly the impact of COVID-19, on patients awaiting AF ablation, via a bespoke questionnaire. METHODS: Patients awaiting AF ablation were sent two QoL questionnaires (Atrial Fibrillation Effect on QualiTy of Life (AFEQT) and EuroQol 5D (EQ5D-5L)) and the bespoke questionnaire. At a separate time point, patients were categorised as C1-urgent, C2-priority or C3-routine by their cardiologist based on review of clinic letters. RESULTS: There were 118 patients included with priority categorisation available for 86 patients. Median AFEQT scores were lower in C2 (30.4; 17.2-51.9) vs C3 patients (56.5; 32.1-74.1; p<0.01). Unplanned admission occurred in 3 patients in C3 with AFEQT scores of <40. Although 65 patients had AF symptoms during the pandemic, 43.1% did not seek help where they ordinarily would have. An exercise frequency of ≥3-4 times a week was associated with higher AFEQT (56.5; 41.2-74.1; p<0.001) and EQ5D (0.84; 0.74-0.88; p<0.0001) scores. CONCLUSION: The QoL of patients awaiting AF ablation is impaired and AFEQT helps to identify patients at risk of admission, over and above physician assessment. COVID-19 influenced patients seeking medical attention with symptomatic AF when they normally would. Regular exercise is associated with better QoL in patients awaiting AF ablation.

Cardiac sarcoidosis in an adult person with cystic fibrosis: a case report.

Cardiac sarcoidosis and cystic fibrosis (CF) are both rare conditions and their co-existence has not previously been noted in adults. For the first time we report a case of isolated cardiac sarcoidosis in a woman with CF, and discuss the possible combined aetiological factors. As the life expectancy of people with CF continues to increase, clinicians should be aware of the emergence of concomitant inflammatory conditions typically diagnosed in adulthood, and the diagnostic challenges this may present.

Local impedance for the optimization of radiofrequency lesion delivery: A review of bench and clinical data.

INTRODUCTION: Radiofrequency catheter ablation is a cornerstone of treatment for many cardiac arrhythmias. Progression in three-dimensional mapping and contact-force sensing technologies have improved our capability to achieve success, but challenges still remain. METHODS: In this article, we discuss the importance of overall circuit impedance in radiofrequency lesion formation. This is followed by a review of the literature regarding recently developed "local impedance" technology and its current and future potential applications and limitations, in the context of established surrogate markers currently used to infer effective ablation. RESULTS: We discuss the role of local impedance in assessing myocardial substrate, as well as its role in clinical studies of ablation. We also discuss safety considerations, limitations and ongoing research. CONCLUSION: Local impedance is a novel tool which has the potential to tailor ablation in a manner distinct from other established metrics.

Procedural efficiencies, lesion metrics, and 12-month clinical outcomes for Ablation Index-guided 50 W ablation for atrial fibrillation.

AIMS: The safety of Ablation Index (AI)-guided 50 W ablation for atrial fibrillation (AF) remains uncertain, and mid-term clinical outcomes have not been described. The interplay between AI and its components at 50 W has not been reported. METHODS AND RESULTS: Eighty-eight consecutive AF patients (44% paroxysmal) underwent AI-guided 50 W ablation. Procedural and 12-month clinical outcomes were compared with 93 consecutive controls (65% paroxysmal) who underwent AI-guided ablation using 35-40 W. Posterior wall isolation (PWI) was performed in 44 (50%) and 23 (25%) patients in the 50 and 35-40 W groups, respectively, P < 0.001. The last 10 patients from each group underwent analysis of individual lesions (n = 1230) to explore relationships between different powers and the AI components. Pulmonary vein isolation was successful in all patients. Posterior wall isolation was successful in 41/44 (93.2%) and 22/23 (95.7%) in the 50 and 35-40 W groups, respectively (P = 0.685). Radiofrequency times (20 vs. 26 min, P < 0.001) and total procedure times (130 vs. 156 min, P = 0.002) were significantly lower in the 50 W group. No complication or steam pop was seen in either group. Twelve-month freedom from arrhythmia was similar (80.2% vs. 82.8%, P = 0.918). A higher proportion of lesions in the 50 W group were associated with impedance drop >7 Ω (54.6% vs. 45.5%, P < 0.001). Excessive ablation (AI >600 anteriorly, >500 posteriorly) was more frequent in the 50 W group (9.7% vs. 4.3%, P < 0.001). CONCLUSION: Ablation Index-guided 50 W AF ablation is as safe and effective as lower powers and results in reduced ablation and procedure times. Radiofrequency lesions are more likely to be therapeutic, but there is a higher risk of delivering excessive ablation.

Feasibility of weight loss in obese atrial fibrillation patients attending a specialist arrhythmia clinic and its impact on ablation outcomes.

BACKGROUND: The feasibility of significant weight reduction in a specialist arrhythmia service, and its impact on atrial fibrillation (AF) ablation outcomes are unclear. We aimed to assess these factors in a real-world cohort in the United Kingdom. METHODS: Patients from one specialized arrhythmia clinic were instructed to follow the "Intermittent Fasting 5:2 diet" ("diet group", n = 50), and their outcomes were compared to a propensity matched cohort who received no specific dietary advice ("control group", n = 42). The primary outcome was recurrence of AF or atrial tachycardia (AT) at 12 months postablation, with or without drugs. RESULTS: Body weight and body mass index (BMI) at baseline were 105.0 (±15.3) kgs and 36.0 (±4.0), respectively. Baseline characteristics between the two groups were comparable. Patients in diet group experienced a mean weight loss of 8.2 (±7.1) kgs prior to AF ablation (P < .01 for comparison to baseline and control group). About 14 (28%) patients in the diet group lost >10% of their body weight. Overall, 11 (22%) patients in the diet group and five (12%) in the control group had AF recurrence at 1 year, P = .21. AF recurrence was similar in patients with BMI ≥ 35 (15%) as compared to BMI < 35 (19%), P = .60. There was one procedural complication (pulmonary edema) in the diet group. CONCLUSION: It is feasible to achieve significant weight reduction in obese AF patients in a specialist arrhythmia clinic setting with unsupervised dietary advice. Low rates of procedural complications and excellent medium-term success rates were observed in this traditionally challenging population. Additional improvements in outcomes were not demonstrable in patients who exhibited significant weight loss.

The feasibility and effectiveness of a streamlined single-catheter approach for radiofrequency atrial fibrillation ablation.

BACKGROUND: Catheter ablation for atrial fibrillation (AF) traditionally requires the use of circular mapping catheter (CMC) for pulmonary vein isolation (PVI). This study aimed to assess the feasibility and effectiveness of a CMC-free approach for AF ablation performed by a contiguous optimized (CLOSE) ablation protocol. METHODS: A CLOSE-guided and CMC-free PVI protocol with a single transseptal puncture was attempted in 67 patients with AF. Left atrial (LA) CARTO voltage mapping was performed with the ablation catheter pre- and postablation to demonstrate entry block into the pulmonary veins, and pacing maneuvers were used to confirm exit block. RESULTS: The CMC-free approach was successful in achieving PVI in 66 (98.5%) cases, with procedure time of 148 ± 32 minutes, ablation time of 27.5 ± 5.7 minutes, and fluoroscopy time of 7.8 ± 1.0 minutes. First-pass PVI was seen in 58(86.5%) patients, and pacing maneuvers successfully identified the residual gap in eight of the other nine cases. No complication was observed. At 12 months follow-up, 60 (89.6%) patients remained free from AF. The CMC-free approach resulted in a cost saving of £47,190. CONCLUSION: A CMC-free CLOSE-guided PVI approach is feasible, safe, and cost-saving, and is associated with excellent clinical outcomes at 1 year.

Reverse electrical and structural remodeling of the left atrium occurs early after pulmonary vein isolation for persistent atrial fibrillation.

PURPOSE: Adverse left atrial (LA) remodeling is known to be associated with persistent atrial fibrillation (PeAF). The time course and pattern of reversal of LA remodeling following catheter ablation is poorly understood. We aimed to evaluate LA chamber volumes and dimensions, LA conduction velocities, and LA bipolar voltages at baseline and at 2 months after catheter ablation for PeAF. METHODS: Twenty-three patients with PeAF underwent detailed LA mapping during fixed rate atrial pacing using the CARTO3 navigation system prior to undergoing pulmonary vein isolation. All patients returned for protocol-mandated repeat electrophysiology study at 2 months, irrespective of symptoms or arrhythmia recurrence, during which all measurements were repeated using an identical mapping protocol. Patients then underwent daily ECG monitoring for 12 months. RESULTS: Nineteen out of twenty-three (83.6%) patients had durable PVI of all veins at repeat electrophysiology study, while 4 (17.4%) patients had late reconnection of a single vein each. In the blinded offline analysis, LA volume at follow-up was significantly lower as compared with baseline (55 ± 14 mL/m2 vs. 65 ± 15 mL/m2, P < 0.001). LA conduction velocities were significantly greater at 2 months (0.90 ± 0.13 m/s vs. 0.78 ± 0.13 m/s, P = 0.01). There was non-uniform regional LA voltage evolution, with a significant increase in bipolar voltages observed on the LA posterior wall (2.18 ± 0.85 mV vs. 1.83 ± 0.49 mV, P = 0.04), but not elsewhere. Individual variables of remodeling were not associated with AF recurrence. CONCLUSION: Significant structural and electrical reverse remodeling of the LA can be seen as early as 2 months following successful catheter ablation for PeAF.

Ultra-High-Density Activation Mapping to Aid Isthmus Identification of Atrial Tachycardias in Congenital Heart Disease.

OBJECTIVES: A new electroanatomic mapping system (Rhythmia, Boston Scientific, Marlborough, Massachusetts) using a 64-electrode mapping basket is now available; we systematically assessed its use in complex congenital heart disease (CHD). BACKGROUND: The incidence of atrial arrhythmias post-surgery for CHD is high. Catheter ablation has emerged as an effective treatment, but is hampered by limitations in the mapping system's ability to accurately define the tachycardia circuit. METHODS: Mapping and ablation data of 61 patients with CHD (35 males, age 45 ± 14 years) from 8 tertiary centers were reviewed. RESULTS: Causes were as follows: Transposition of Great Arteries (atrial switch) (n = 7); univentricular physiology (Fontans) (n = 8); Tetralogy of Fallot (n = 10); atrial septal defect (ASD) repair (n = 15); tricuspid valve (TV) anomalies (n = 10); and other (n = 11). The total number of atrial arrhythmias was 86. Circuits were predominantly around the tricuspid valve (n = 37), atriotomy scar (n = 10), or ASD patch (n = 4). Although the majority of peri-tricuspid circuits were cavo-tricuspid-isthmus dependent (n = 30), they could follow a complex route between the annulus and septal resection, ASD patch, coronary sinus, or atriotomy. Immediate ablation success was achieved in all but 2 cases; with follow-up of 12 ± 8 months, 7 patients had recurrence. CONCLUSIONS: We demonstrate the feasibility of the basket catheter for mapping complex CHD arrhythmias, including with transbaffle and transhepatic access. Although the circuits often involve predictable anatomic landmarks, the precise critical isthmus is often difficult to predict empirically. Ultra-high-density mapping enables elucidation of circuits in this complex anatomy and allows successful treatment at the isthmus with a minimal lesion set.

Same-day discharge in selected patients undergoing atrial fibrillation ablation.

BACKGROUND: Atrial fibrillation (AF) ablation is a complex procedure, generally requiring at least one overnight hospital stay. We investigated the safety and feasibility of early mobilization and same-day discharge following streamlined peri-ablation management for AF. METHODS: From 2014, we offered same-day discharge to selected patients who underwent uncomplicated AF ablation on the morning lists, with ultrasound-guided femoral access, uninterrupted warfarin or minimal interruption in novel oral anticoagulants, and reversal of intraprocedural heparin with protamine. Patients were discharged 6-8 h postprocedure and offered access to a dedicated nurse helpline. RESULTS: Of 1599 AF ablation cases performed from April 2014 to March 2017, 811 (50.7%) were performed on the morning lists and 169/811 (20.8%) were discharged on the same day. Excluding 26 research cases, 1/143 (0.7%) had transient right phrenic nerve palsy and five (3.5%) cases experienced minor problems that did not preclude same-day discharge; three (2.1%) needed rehospitalization postdischarge: one for pericarditic chest pain and two for nausea/vomiting. Compared to 642 overnight cases, day-case procedures were shorter, more likely to be redos, to be performed under sedation rather than general anesthesia, and less likely to involve linear lesions and electrical cardioversion. There were no significant differences in patient age, gender, body mass index, CHA2 DS2 -VASc, in preprocedural anticoagulation regimen (warfarin vs novel anticoagulants vs no anticoagulation) and in choice of ablation method (cryoballoon vs radiofrequency). CONCLUSIONS: Selective same-day discharge after AF ablation is safe and feasible using a streamlined peri-procedural care protocol. Wider adoption can potentially reduce health-care costs while improving patient experience.

Early experience of thoracoscopic vs. catheter ablation for atrial fibrillation.

AIMS: Video-assisted thoracoscopic surgery (VATS) ablation has been advocated as a treatment option for non-paroxysmal atrial fibrillation (AF) in recent guidelines. Real-life data on its safety and efficacy during a centre's early experience are sparse. METHODS AND RESULTS: Thirty patients (28 persistent/longstanding persistent AF) underwent standalone VATS ablation for AF by an experienced thoracoscopic surgeon, with the first 20 cases proctored by external surgeons. Procedural and follow-up outcomes were collected prospectively, and compared with 90 propensity-matched patients undergoing contemporaneous catheter ablation (CA). Six (20.0%) patients undergoing VATS ablation experienced ≥1 major complication (death n = 1, stroke n = 2, conversion to sternotomy n = 3, and phrenic nerve injury n = 2). This was significantly higher than the 1.1% major complication rate (tamponade requiring drainage n = 1) seen with CA (P < 0.001). Twelve-month single procedure arrhythmia-free survival rates without antiarrhythmic drugs were 56% in the VATS and 57% in the CA cohorts (P = 0.22), and 78% and 80%, respectively given an additional CA and antiarrhythmic drugs (P = 0.32). CONCLUSION: During a centre's early experience, VATS ablation may have similar success rates to those from an established CA service, but carry a greater risk of major complications. Those embarking on a programme of VATS AF ablation should be aware that complication and success rates may differ from those reported by selected high-volume centres.