Catheter ablation for persistent atrial fibrillation: patterns of recurrence and impact on quality of life and health care utilization.

BACKGROUND AND AIMS: Patterns of atrial fibrillation (AF) recurrence post-catheter ablation for persistent AF (PsAF) are not well described. This study aimed to describe the pattern of AF recurrence seen following catheter ablation for PsAF and the implications for healthcare utilization and quality of life (QoL). METHODS: This was a post-hoc analysis of the CAPLA study, an international, multicentre study that randomized patients with symptomatic PsAF to pulmonary vein isolation plus posterior wall isolation or pulmonary vein isolation alone. Patients underwent twice daily single lead ECG, implantable device monitoring or three monthly Holter monitoring. RESULTS: 154 of 333 (46.2%) patients (median age 67.3 years, 28% female) experienced AF recurrence at 12-month follow-up. Recurrence was paroxysmal in 97 (63%) patients and persistent in 57 (37%). Recurrence type did not differ between randomization groups (P = .508). Median AF burden was 27.4% in PsAF recurrence and .9% in paroxysmal AF (PAF) recurrence (P < .001). Patients with PsAF recurrence had lower baseline left ventricular ejection fraction (PsAF 50% vs. PAF 60%, P < .001) and larger left atrial volume (PsAF 54.2 ± 19.3 mL/m² vs. PAF 44.8 ± 11.6 mL/m², P = .008). Healthcare utilization was significantly higher in PsAF (45 patients [78.9%]) vs. PAF recurrence (45 patients [46.4%], P < .001) and lowest in those without recurrence (17 patients [9.5%], P < .001). Patients without AF recurrence had greater improvements in QoL as assessed by the Atrial Fibrillation Effect on Quality-of-Life (AFEQT) questionnaire (Δ33.3 ± 25.2 points) compared to those with PAF (Δ24.0 ± 25.0 points, P = .012) or PsAF (Δ13.4 ± 22.9 points, P < .001) recurrence. CONCLUSIONS: AF recurrence is more often paroxysmal after catheter ablation for PsAF irrespective of ablation strategy. Recurrent PsAF was associated with higher AF burden, increased healthcare utilization and antiarrhythmic drug use. The type of AF recurrence and AF burden may be considered important endpoints in clinical trials investigating ablation of PsAF.

Caudal fluoroscopic guidance for the insertion of transvenous pacing leads.

BACKGROUND: Pneumothorax is a well-recognized complication of cardiac implantable electronic device (CIED) insertion. While AP fluoroscopy alone is the most commonly imaging technique for subclavian or axillary access, caudal fluoroscopy (angle 40°) is routinely used at our institution. The caudal view provides additional separation of the first rib and clavicle and may reduce the risk of pneumothorax. We assessed outcomes at our institution of AP and caudal fluoroscopic guided pacing lead insertion. METHODS: Retrospective cohort study of consecutive patients undergoing transvenous lead insertion for pacemakers, defibrillators, and cardiac resynchronization therapy devices between 2011 and 2023. Both de novo and lead replacement/upgrade procedures were included. Data were extracted from operative, radiology, and discharge reports. All patients underwent postprocedure chest radiography. RESULTS: Three thousand two hundred fifty-two patients underwent insertion of pacing leads between February 2011 and March 2023. Mean age was 71.1 years (range 16-102) and 66.7% were male. Most (n = 2536; 78.0%) procedures used caudal guidance to obtain venous access, while 716 (22.0%) procedures used AP guidance alone. Pneumothoraxes occurred in five (0.2%) patients in the caudal group and five (0.7%) patients in the AP group (p = .03). Subclavian contrast venography was performed less frequently in the caudal group (26.2% vs. 42.7%, p < .01). CONCLUSION: Caudal fluoroscopy for axillary/subclavian access is associated with a lower rate of pneumothorax and contrast venography compared with an AP approach.

Aberrancy masquerading as ventricular tachycardia: Importance of invasive electrophysiology study for diagnosis of wide complex tachycardias.

BACKGROUND: Differentiation between ventricular tachycardia (VT) and supraventricular tachycardia (SVT) with aberrancy based on the 12­lead ECG alone can be imprecise. Implantable cardiac defibrillators (ICD) may be inserted for presumed VT, particularly in patients with syncopal presentation or atypical aberrancy patterns. Accurate diagnosis of these patients facilitated by an electrophysiology study (EPS) may alter diagnosis and management. METHODS: We present a prospective collection of cases across 3 cardiac centers of consecutive patients with WCT presumed to be VT who were referred for consideration of an ICD, and in whom further evaluation including an EPS ultimately demonstrated SVT with aberrancy as the culprit arrhythmia. RESULTS: 22 patients were identified (17 male, mean age 50±13 years. Available rhythm data at the time of referral was presumptively diagnosed as monomorphic VT in 16 patients and polymorphic VT in 6 patients. Underlying structural heart disease was present in 20 (91%). EPS resulted in a diagnosis of SVT with aberrancy in all cases: comprising AV nodal re-entry tachycardia (n=10), orthodromic reciprocating tachycardia (n=3), focal atrial tachycardia (n=3), AF/AFL (n=3) and 'double fire' tachycardia (n=2). 21 (95%) patients underwent successful ablation. All patients remained free of arrhythmia recurrence at a median of 3.4 years of follow-up. ICD insertion was obviated in 18 (82%) patients, with 1 patient proceeding to ICD extraction. CONCLUSION: SVT with atypical aberrancy may mimic monomorphic or polymorphic VT. Careful examination of all available rhythm data and consideration of an EPS can confirm SVT and obviate the need for ICD therapy.

New-onset atrial fibrillation prediction: the HARMS2-AF risk score.

AIMS: Lifestyle risk factors are a modifiable target in atrial fibrillation (AF) management. The relative contribution of individual lifestyle risk factors to AF development has not been described. Development and validation of an AF lifestyle risk score to identify individuals at risk of AF in the general population are the aims of the study. METHODS AND RESULTS: The UK Biobank (UKB) and Framingham Heart Study (FHS) are large prospective cohorts with outcomes measured >10 years. Incident AF was based on International Classification of Diseases version 10 coding. Prior AF was excluded. Cox proportional hazards regression identified independent AF predictors, which were evaluated in a multivariable model. A weighted score was developed in the UKB and externally validated in the FHS. Kaplan-Meier estimates ascertained the risk of AF development. Among 314 280 UKB participants, AF incidence was 5.7%, with median time to AF 7.6 years (interquartile range 4.5-10.2). Hypertension, age, body mass index, male sex, sleep apnoea, smoking, and alcohol were predictive variables (all P < 0.001); physical inactivity [hazard ratio (HR) 1.01, 95% confidence interval (CI) 0.96-1.05, P = 0.80] and diabetes (HR 1.03, 95% CI 0.97-1.09, P = 0·38) were not significant. The HARMS2-AF score had similar predictive performance [area under the curve (AUC) 0.782] to the unweighted model (AUC 0.802) in the UKB. External validation in the FHS (AF incidence 6.0% of 7171 participants) demonstrated an AUC of 0.757 (95% CI 0.735-0.779). A higher HARMS2-AF score (≥5 points) was associated with a heightened AF risk (score 5-9: HR 12.79; score 10-14: HR 38.70). The HARMS2-AF risk model outperformed the Framingham-AF (AUC 0.568) and ARIC (AUC 0.713) risk models (both P < 0.001) and was comparable to the CHARGE-AF risk score (AUC 0.754, P = 0.73). CONCLUSION: The HARMS2-AF score is a novel lifestyle risk score which may help identify individuals at risk of AF in the general community and assist population screening.

Alcohol Abstinence in Drinkers with Atrial Fibrillation.

BACKGROUND: Excessive alcohol consumption is associated with incident atrial fibrillation and adverse atrial remodeling; however, the effect of abstinence from alcohol on secondary prevention of atrial fibrillation is unclear. METHODS: We conducted a multicenter, prospective, open-label, randomized, controlled trial at six hospitals in Australia. Adults who consumed 10 or more standard drinks (with 1 standard drink containing approximately 12 g of pure alcohol) per week and who had paroxysmal or persistent atrial fibrillation in sinus rhythm at baseline were randomly assigned in a 1:1 ratio to either abstain from alcohol or continue their usual alcohol consumption. The two primary end points were freedom from recurrence of atrial fibrillation (after a 2-week "blanking period") and total atrial fibrillation burden (proportion of time in atrial fibrillation) during 6 months of follow-up. RESULTS: Of 140 patients who underwent randomization (85% men; mean [±SD] age, 62±9 years), 70 were assigned to the abstinence group and 70 to the control group. Patients in the abstinence group reduced their alcohol intake from 16.8±7.7 to 2.1±3.7 standard drinks per week (a reduction of 87.5%), and patients in the control group reduced their alcohol intake from 16.4±6.9 to 13.2±6.5 drinks per week (a reduction of 19.5%). After a 2-week blanking period, atrial fibrillation recurred in 37 of 70 patients (53%) in the abstinence group and in 51 of 70 patients (73%) in the control group. The abstinence group had a longer period before recurrence of atrial fibrillation than the control group (hazard ratio, 0.55; 95% confidence interval, 0.36 to 0.84; P = 0.005). The atrial fibrillation burden over 6 months of follow-up was significantly lower in the abstinence group than in the control group (median percentage of time in atrial fibrillation, 0.5% [interquartile range, 0.0 to 3.0] vs. 1.2% [interquartile range, 0.0 to 10.3]; P = 0.01). CONCLUSIONS: Abstinence from alcohol reduced arrhythmia recurrences in regular drinkers with atrial fibrillation. (Funded by the Government of Victoria Operational Infrastructure Support Program and others; Australian New Zealand Clinical Trials Registry number, ACTRN12616000256471.).

The impact of age on ablation outcomes in AF-mediated cardiomyopathy.

INTRODUCTION: The absence of ventricular scar in patients with atrial fibrillation (AF) and systolic heart failure (HF) predicts left ventricular (LV) recovery following AF ablation. It is unknown whether age impacts the degree of LV recovery, reverse remodeling, or AF recurrence following catheter ablation (CA) among this population. OBJECTIVES: To evaluate the impact of age on LV recovery and AF recurrence in a population with AF and systolic HF without fibrosis (termed AF-mediated cardiomyopathy) following CA. METHODS: Consecutive patients undergoing CA between 2013 and 2021 with LV ejection fraction (LVEF) < 45% and absence of cardiac magnetic resonance imaging (CMR) detected LV myocardial fibrosis were stratified by age (<65 vs. ≥65 years). Following CA, participants underwent remote rhythm monitoring for 12 months with repeat CMR for HF surveillance. RESULTS: The study population consisted of 70 patients (10% female, mean LVEF 33 ± 9%), stratified into younger (age < 65 years, 63%) and older (age ≥ 65 years, 37%) cohorts. Baseline comorbidities, LVEF (34 ± 9 vs. 33 ± 8 ≥65 years, p = .686), atrial and ventricular dimensions (left atrial volume index: 55 ± 21 vs. 56 ± 14 mL/m2 age ≥ 65, p = .834; indexed left ventricular end-diastolic volume: 108 ± 40 vs. 104 ± 28 mL/m2 age ≥ 65, p = .681), pharmacotherapy and ablation strategy (pulmonary vein isolation in all; posterior wall isolation in 27% vs. 19% age ≥ 65, p = .448; cavotricuspid isthmus in 9% vs. 11.5% age ≥ 65) were comparable (all p > .05) albeit a higher CHADS2 VASc score in the older cohort (2.7 ± 0.9 vs. 1.6 ± 0.6 age < 65, p < .001).   Freedom from AF was comparable (hazard ratio: 0.65, 95% confidence interval: 0.38-1.48, LogRank p = .283) as was AF burden [0% (interquartile range, IQR: 0.0-2.1) vs. age ≥ 65: [0% (IQR 0.0-1.7), p = .516], irrespective of age. There was a significant improvement in LV systolic function in both groups (ΔLVEF + 21 ± 14% vs. +21 ± 12% age ≥ 65, p = .913), with LV recovery in the vast majority (73% vs. 69%, respectively, p = .759) at 13 (IQR: 12-16) months. This was accompanied by comparable improvements in functional status (New York Heart Association class p = .851; 6-min walk distance 50 ± 61 vs. 93 ± 134 m in age ≥ 65, p = .066), biomarkers (ΔN-terminal-pro brain natriuretic peptide -139 ± 246 vs. -168 ± 181 age ≥ 65,p = .629) and HF symptoms (Short Form-36 survey Δphysical component summary p = .483/Δmental component summary, p = .841). CONCLUSION: In patients undergoing CA for AF with systolic HF in the absence of ventricular scar, comparable improvements in ventricular function, symptoms, and freedom from AF are achieved irrespective of age.

Higher power short duration vs. lower power longer duration posterior wall ablation for atrial fibrillation and oesophageal injury outcomes: a prospective multi-centre randomized controlled study (Hi-Lo HEAT trial).

AIMS: Radiofrequency (RF) ablation for pulmonary vein isolation (PVI) in atrial fibrillation (AF) is associated with the risk of oesophageal thermal injury (ETI). Higher power short duration (HPSD) ablation results in preferential local resistive heating over distal conductive heating. Although HPSD has become increasingly common, no randomized study has compared ETI risk with conventional lower power longer duration (LPLD) ablation. This study aims to compare HPSD vs. LPLD ablation on ETI risk. METHODS AND RESULTS: Eighty-eight patients were randomized 1:1 to HPSD or LPLD posterior wall (PW) ablation. Posterior wall ablation was 40 W (HPSD group) or 25 W (LPLD group), with target AI (ablation index) 400/LSI (lesion size index) 4. Anterior wall ablation was 40-50 W, with a target AI 500-550/LSI 5-5.5. Endoscopy was performed on Day 1. The primary endpoint was ETI incidence. The mean age was 61 ± 9 years (31% females). The incidence of ETI (superficial ulcers n = 4) was 4.5%, with equal occurrence in HPSD and LPLD (P = 1.0). There was no difference in the median value of maximal oesophageal temperature (HPSD 38.6°C vs. LPLD 38.7°C, P = 0.43), or the median number of lesions per patient with temperature rise above 39°C (HPSD 1.5 vs. LPLD 2, P = 0.93). Radiofrequency ablation time (23.8 vs. 29.7 min, P < 0.01), PVI duration (46.5 vs. 59 min, P = 0.01), and procedure duration (133 vs. 150 min, P = 0.05) were reduced in HPSD. After a median follow-up of 12 months, AF recurrence was lower in HPSD (15.9% vs. LPLD 34.1%; hazard ratio 0.42, log-rank P = 0.04). CONCLUSION: Higher power short duration ablation was associated with similarly low rates of ETI and shorter total/PVI RF ablation times when compared with LPLD ablation. Higher power short duration ablation is a safe and efficacious approach to PVI.

Atrial Fibrillation Catheter Ablation vs Medical Therapy and Psychological Distress: A Randomized Clinical Trial.

Importance: The impact of atrial fibrillation (AF) catheter ablation on mental health outcomes is not well understood. Objective: To determine whether AF catheter ablation is associated with greater improvements in markers of psychological distress compared with medical therapy alone. Design, Setting, and Participants: The Randomized Evaluation of the Impact of Catheter Ablation on Psychological Distress in Atrial Fibrillation (REMEDIAL) study was a randomized trial of symptomatic participants conducted in 2 AF centers in Australia between June 2018 and March 2021. Interventions: Participants were randomized to receive AF catheter ablation (n = 52) or medical therapy (n = 48). Main Outcomes and Measures: The primary outcome was Hospital Anxiety and Depression Scale (HADS) score at 12 months. Secondary outcomes included follow-up assessments of prevalence of severe psychological distress (HADS score >15), anxiety HADS score, depression HADS score, and Beck Depression Inventory-II (BDI-II) score. Arrhythmia recurrence and AF burden data were also analyzed. Results: A total of 100 participants were randomized (mean age, 59 [12] years; 31 [32%] women; 54% with paroxysmal AF). Successful pulmonary vein isolation was achieved in all participants in the ablation group. The combined HADS score was lower in the ablation group vs the medical group at 6 months (8.2 [5.4] vs 11.9 [7.2]; P = .006) and at 12 months (7.6 [5.3] vs 11.8 [8.6]; between-group difference, -4.17 [95% CI, -7.04 to -1.31]; P = .005). Similarly, the prevalence of severe psychological distress was lower in the ablation group vs the medical therapy group at 6 months (14.2% vs 34%; P = .02) and at 12 months (10.2% vs 31.9%; P = .01), as was the anxiety HADS score at 6 months (4.7 [3.2] vs 6.4 [3.9]; P = .02) and 12 months (4.5 [3.3] vs 6.6 [4.8]; P = .02); the depression HADS score at 3 months (3.7 [2.6] vs 5.2 [4.0]; P = .047), 6 months (3.4 [2.7] vs 5.5 [3.9]; P = .004), and 12 months (3.1 [2.6] vs 5.2 [3.9]; P = .004); and the BDI-II score at 6 months (7.2 [6.1] vs 11.5 [9.0]; P = .01) and 12 months (6.6 [7.2] vs 10.9 [8.2]; P = .01). The median (IQR) AF burden in the ablation group was lower than in the medical therapy group (0% [0%-3.22%] vs 15.5% [1.0%-45.9%]; P < .001). Conclusion and Relevance: In this trial of participants with symptomatic AF, improvement in psychological symptoms of anxiety and depression was observed with catheter ablation, but not medical therapy. Trial Registration: ANZCTR Identifier: ACTRN12618000062224.

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: The CAPLA Randomized Clinical Trial.

Importance: Pulmonary vein isolation (PVI) alone is less effective in patients with persistent atrial fibrillation (AF) compared with paroxysmal AF. The left atrial posterior wall may contribute to maintenance of persistent AF, and posterior wall isolation (PWI) is a common PVI adjunct. However, PWI has not been subjected to randomized comparison. Objective: To compare PVI with PWI vs PVI alone in patients with persistent AF undergoing first-time catheter ablation. Design, Setting, and Participants: Investigator initiated, multicenter, randomized clinical trial involving 11 centers in 3 countries (Australia, Canada, UK). Symptomatic patients with persistent AF were randomized 1:1 to either PVI with PWI or PVI alone. Patients were enrolled July 2018-March 2021, with 1-year follow-up completed March 2022. Interventions: The PVI with PWI group (n = 170) underwent wide antral pulmonary vein isolation followed by posterior wall isolation involving linear ablation at the roof and floor to achieve electrical isolation. The PVI-alone group (n = 168) underwent wide antral pulmonary vein isolation alone. Main Outcomes and Measures: Primary end point was freedom from any documented atrial arrhythmia of more than 30 seconds without antiarrhythmic medication at 12 months, after a single ablation procedure. The 23 secondary outcomes included freedom from atrial arrhythmia with/without antiarrhythmic medication after multiple procedures, freedom from symptomatic AF with/without antiarrhythmic medication after multiple procedures, AF burden between study groups at 12 months, procedural outcomes, and complications. Results: Among 338 patients randomized (median age, 65.6 [IQR, 13.1] years; 76.9% men), 330 (97.6%) completed the study. After 12 months, 89 patients (52.4%) assigned to PVI with PWI were free from recurrent atrial arrhythmia without antiarrhythmic medication after a single procedure, compared with 90 (53.6%) assigned to PVI alone (between-group difference, -1.2%; hazard ratio [HR], 0.99 [95% CI, 0.73-1.36]; P = .98). Of the secondary end points, 9 showed no significant difference, including freedom from atrial arrhythmia with/without antiarrhythmic medication after multiple procedures (58.2% for PVI with PWI vs 60.1% for PVI alone; HR, 1.10 [95% CI, 0.79-1.55]; P = .57), freedom from symptomatic AF with/without antiarrhythmic medication after multiple procedures (68.2% vs 72%; HR, 1.20 [95% CI, 0.80-1.78]; P = .36) or AF burden (0% [IQR, 0%-2.3%] vs 0% [IQR, 0%-2.8%], P = .47). Mean procedural times (142 [SD, 69] vs 121 [SD, 57] minutes, P < .001) and ablation times (34 [SD, 21] vs 28 [SD, 12] minutes, P < .001) were significantly shorter for PVI alone. There were 6 complications for PVI with PWI and 4 for PVI alone. Conclusions and Relevance: In patients undergoing first-time catheter ablation for persistent AF, the addition of PWI to PVI alone did not significantly improve freedom from atrial arrhythmia at 12 months compared with PVI alone. These findings do not support the empirical inclusion of PWI for ablation of persistent AF. Trial Registration: anzctr.org.au Identifier: ACTRN12616001436460.

Catheter ablation for persistent atrial fibrillation: A multicenter randomized trial of pulmonary vein isolation (PVI) versus PVI with posterior left atrial wall isolation (PWI) - The CAPLA study.

BACKGROUND: The success of pulmonary vein isolation (PVI) is reduced in persistent AF (PsAF) compared to paroxysmal AF. Adjunctive ablation strategies have failed to show consistent incremental benefit over PVI alone in randomized studies. The left atrial posterior wall is a potential source of non-PV triggers and atrial substrate which may promote the initiation and maintenance of PsAF. Adding posterior wall isolation (PWI) to PVI had shown conflicting outcomes, with earlier studies confounded by methodological limitations. OBJECTIVES: To determine whether combining PWI with PVI significantly improves freedom from AF recurrence, compared to PVI alone, in patients with PsAF. METHODS: This is a multi-center, prospective, international randomized clinical trial. 338 patients with symptomatic PsAF refractory to anti-arrhythmic therapy (AAD) will be randomized to either PVI alone or PVI with PWI in a 1:1 ratio. PVI involves wide antral circumferential pulmonary vein (PV) isolation, utilizing contact force sensing ablation catheters. PWI involves the creation of a floor line connecting the inferior aspect of the PVs, and a roof line connecting the superior aspect of the PVs. Follow up is for a minimum of 12 months with rhythm monitoring via implantable cardiac device and/or loop monitor, or frequent intermittent monitoring with an ECG device. The primary outcome is freedom from any documented atrial arrhythmia of > 30 seconds off AAD at 12 months, after a single ablation procedure. CONCLUSIONS: This randomized study aims to determine the success and safety of adjunctive PWI to PVI in patients with persistent AF.

A prospective evaluation of the impact of individual RF applications for slow pathway ablation for AVNRT: Markers of acute success.

BACKGROUND: Catheter ablation is highly effective for atrioventricular nodal re-entrant tachycardia (AVNRT). Generally junctional rhythm (JR) is an accepted requirement for successful ablation however there is a lack of detailed prospective studies to determine the characteristics of JR and the impact on slow pathway conduction. METHODS: Multicentre prospective observational study evaluating the impact of individual radiofrequency (RF) applications in typical AVNRT (slow/fast). Characteristics of JR during ablation were documented and detailed testing was performed after every RF application to determine outcome. Procedural success was defined as ≤1 AV nodal echo. RESULTS: Sixty-seven patients were included (mean age 53 ± 18years, 57% female and a history of SVT 2.9 ± 4.7 years). RF (50w, 60°) ablation for AVNRT was applied in 301 locations with JR in 178 (59%). Successful slow pathway modification was achieved in 66 (99%) patients with slow pathway block in 30 (46%). Success was associated with JR in all patients. Success was achieved in six patients with RF < 10 s. There was no significant difference in the CL of JR during RF between effective (587 ± 150 ms) versus ineffective (611 ± 193 ms, p = .4) applications. Inadvertent junctional beat-atrial (JA) block with immediate termination of RF was observed in 19 (28%) patients with AVNRT no longer inducible in 14 (74%). Freedom from SVT was achieved in 66 (99%) patients at a mean follow up of 15 ± 6 months. CONCLUSION: In this prospective study, JR was required during RF for acute success in AVNRT. Cycle length of JR during RF was not predictive of success. Although unintended JA block during faster JR was associated with slow pathway block, this is a precursor to fast pathway block and should not be intentionally targeted.

Interpretation of clinical studies in electrophysiology: statistical considerations for the clinician.

Atrial fibrillation (AF) outcome studies play an essential role in the development of clinical evidence to improve the management of AF patients. Understanding the statistical considerations involved in study design and interpretation is crucial if electrophysiologists are to change practice. In this review, with the guidance of a medical statistician and a clinical trialist we provide an overview of important statistical issues for the clinician, with a focus on clinical studies in AF ablation. Various types of study designs including randomized controlled trials, superiority, and non-inferiority studies are described, along with their implications and limitations. Appropriate sample size calculation is fundamental to ensure statistical power and efficient resource use. Multiplicity in study endpoints is useful to encapsulate the varied effects of an intervention/treatment, although statistical adjustments are required to account for this. Finally, we discuss the limitations with the current primary endpoint used in AF ablation studies, namely, freedom from atrial tachyarrhythmia of >30 seconds, and propose AF burden as a more relevant primary endpoint, based on findings from recent clinical studies. However, technical challenges need to be overcome before AF burden can be routinely adopted, especially the need for non-invasive, long-term monitoring. The emergence of newer technologies, particularly wearable technology, offers significant promise in filling this gap.

Sleep apnoea has a dose-dependent effect on atrial remodelling in paroxysmal but not persistent atrial fibrillation: a high-density mapping study.

AIMS: Obstructive sleep apnoea (OSA) associates with atrial fibrillation (AF), but the relationship of OSA severity and AF phenotype with the atrial substrate remains poorly defined. We sought to define the atrial substrate across the spectrum of OSA severity utilizing high-density mapping. METHODS AND RESULTS: Sixty-six consecutive patients (male 71%, age 61 ± 9) having AF ablation (paroxysmal AF 36, persistent AF 30) were recruited. All patents underwent formal overnight polysomnography and high-density left atrial (LA) mapping (mean 2351 ± 1244 points) in paced rhythm. Apnoea-hypopnoea index (AHI) (mean 21 ± 18) associated with lower voltage (-0.34, P = 0.005), increased complex points (r = 0.43, P < 0.001), more low-voltage areas (r = 0.42, P < 0.001), and greater voltage heterogeneity (r = 0.39, P = 0.001), and persisted after multivariable adjustment. Atrial conduction heterogeneity (r = 0.24, P = 0.025) but not conduction velocity (r = -0.09, P = 0.50) associated with AHI. Patchy regions of low voltage that co-localized with slowed conduction defined the atrial substrate in paroxysmal AF, while a diffuse atrial substrate predominated in persistent AF. The association of AHI with remodelling was most apparent among paroxysmal AF [LA voltage: paroxysmal AF -0.015 (-0.025, -0.005), P = 0.004 vs. persistent AF -0.006 (-0.017, 0.005), P = 0.30]. Furthermore, in paroxysmal AF an AHI ≥ 30 defined a threshold at which atrial remodelling became most evident (nil-mild vs. moderate vs. severe: 1.92 ± 0.42 mV vs. 1.84 ± 0.28 mV vs. 1.34 ± 0.41 mV, P = 0.006). In contrast, significant remodelling was observed across all OSA categories in persistent AF (1.67 ± 0.55 mV vs. 1.50 ± 0.66 mV vs. 1.55 ± 0.67 mV, P = 0.82). CONCLUSION: High-density mapping observed that OSA associates with marked atrial remodelling, predominantly among paroxysmal AF cohorts with severe OSA. This may facilitate the identification of AF patients that stand to derive the greatest benefit from OSA management.

Approach to ablative management of patient with persistent atrial fibrillation and enduring pulmonary vein isolation.

Enduring isolation of the pulmonary veins (PV) is becoming increasingly common in patients undergoing repeat catheter ablation for atrial fibrillation. We describe our approach to ablation strategy in a patient with enduring isolation of PV and briefly discuss the role of non-PV triggers.

Multipolar mapping with the high-density grid catheter compared with conventional point-by-point mapping to guide catheter ablation for focal arrhythmias.

BACKGROUND: Multipolar catheters provide high-density mapping which may reduce the procedural duration and improve the success of catheter ablation (CA) for focal arrhythmias. The high-density grid (HDG) catheter is a 16 electrode mapping catheter with bipole recordings at orthogonal splines. The aim of this study is to compare the clinical and procedural features from a cohort who underwent CA for focal arrhythmias using multipolar mapping (MPM) with age and case-matched cohort using point-by-point (PbyP) mapping. METHODS: Consecutive patients undergoing CA for focal arrhythmias between October 2018 and January 2020 guided by MPM were compared with PbyP mapping with the ablation catheter over a similar period. Demographics, procedural features, and outcomes were compared. RESULTS: A total of 54 patients (27 in MPM vs. 27 in PbyP mapping) underwent CA for 68 focal arrhythmias (26 atrial and 42 ventricular). In the MPM group, the electrogram at the successful site was significantly earlier (39 ± 11 ms) than in the PbyP group (33 ± 7 ms; p = .02). In the MPM group, the mapping time (35 ± 24 vs. 53 ± 31 min in PbyP; p = .03) and procedural duration (126 ± 42 vs. 153 ± 39 min in PbyP; p = .02) were significantly shorter. There was no significant difference in radiofrequency and fluoroscopy times, acute procedural success, and arrhythmia recurrence. CONCLUSION: MPM with the HDG catheter for focal tachycardias identified earlier activation times and was associated with shorter mapping and procedure duration with equivalent success to PbyP mapping.

Cardioversion of atrial fibrillation in obese patients: Results from the Cardioversion-BMI randomized controlled trial.

AIMS: Obesity is associated with higher electrical cardioversion (ECV) failure in persistent atrial fibrillation (PeAF). For ease-of-use, many centers prefer patches over paddles. We assessed the optimum modality and shock vector, as well as the safety and efficacy of the Manual Pressure Augmentation (MPA) technique. METHODS: Patients with obesity (BMI ≥ 30) and PeAF undergoing ECV using a biphasic defibrillator were randomized into one of four arms by modality (adhesive patches or handheld paddles) and shock vector (anteroposterior [AP] or anteroapical [AA]). If the first two shocks (100 and 200 J) failed, then patients received a 200-J shock using the alternative modality (patch or paddle). Shock vector remained unchanged. In an observational substudy, 20 patients with BMI of 35 or more, and who failed ECV at 200 J using both patches/paddles underwent a trial of MPA. RESULTS: In total, 125 patients were randomized between July 2016 and March 2018. First or second shock success was 43 of 63 (68.2%) for patches and 56 of 62 (90.3%) for paddles (P = 0.002). There were 20 crossovers from patches to paddles (12 of 20 third shock success with paddles) and six crossovers from paddles to patches (three of six third shock success with patches). Paddles successfully cardioverted 68 of 82 patients compared with 46 of 69 using patches (82.9% vs 66.7%; P = 0.02). Shock vector did not influence first or second shock success rates (82.0% AP vs 76.6% AA; P = 0.46). MPA was successful in 16 of 20 (80%) who failed in both (patches/paddles), with 360 J required in six of seven cases. CONCLUSION: Routine use of adhesive patches at 200 J is inadequate in obesity. Strategies that improve success include the use of paddles, MPA, and escalation to 360 J.

How to perform posterior wall isolation in catheter ablation for atrial fibrillation.

Catheter ablation has become standard of care in patients with symptomatic atrial fibrillation (AF). Although there have been significant advances in our understanding and technology, a substantial proportion of patients have ongoing AF requiring repeat procedures. Pulmonary vein isolation (PVI) is the cornerstone of AF ablation; however, it is less effective in patients with persistent as opposed to paroxysmal atrial fibrillation. Left atrial posterior wall isolation (PWI) is commonly performed as an adjunct to PVI in patients with persistent AF with nonrandomized studies showing improved outcomes. Anatomical considerations and detailed outline of the various approaches and techniques to performing PWI are detailed, and advantages and pitfalls to assist the clinical electrophysiologist successfully and safely complete PWI are described.

Epicardial CRT-D in a Pacing Dependant Patient Without Transvenous Options.

Implantable cardioverter-defibrillator (ICD) and cardiac resynchronisation therapy (CRT) is generally limited to transvenous techniques especially in pacing-dependant patients. We describe a novel case in which an epicardial CRT-D system was successfully implanted with a two-year follow-up in a pacing-dependant patient.

Predictors of pacemaker requirement in patients receiving implantable loop recorders for unexplained syncope: A systematic review and meta-analysis.

BACKGROUND: Implantable loop recorders (ILRs) are increasingly used to evaluate patients with unexplained syncope. Identification of all predictors of bradycardic syncope and consequent permanent pacemaker (PPM) insertion is of substantial clinical interest as patients in the highest risk category may benefit from upfront pacemaker insertion. OBJECTIVE: We performed a systematic review and meta-analysis to identify risk predictors for PPM insertion in ILR recipients with unexplained syncope. METHODS: An electronic database search (MEDLINE, Embase, Scopus, Cochrane) was performed in June 2023. Studies evaluating ILR recipients with unexplained syncope and recording risk factors for eventual PPM insertion were included. A random effects model was used to calculate the pooled odds ratio (OR) for clinical and electrocardiographic characteristics with respect to future PPM requirement. RESULTS: Eight studies evaluating 1007 ILR recipients were included; 268 patients (26.6%) underwent PPM insertion during study follow-up. PPM recipients were older (mean age, 70.2 ± 15.4 years vs 61.6 ± 19.7 years; P < .001). PR prolongation on baseline electrocardiography was a significant predictor of PPM requirement (pooled OR, 2.91; 95% confidence interval, 1.63-5.20). The presence of distal conduction system disease, encompassing any bundle branch or fascicular block, yielded a pooled OR of 2.88 for PPM insertion (95% confidence interval, 1.53-5.41). Injurious syncope and lack of syncopal prodrome were not significant predictors of PPM insertion. Sinus node dysfunction accounted for 62% of PPM insertions, whereas atrioventricular block accounted for 26%. CONCLUSION: Approximately one-quarter of ILR recipients for unexplained syncope require eventual PPM insertion. Advancing age, PR prolongation, and distal conduction disease are the strongest predictors for PPM requirement.

Prognostic Impact of Diagnosis-to-Ablation Time on Outcomes Following Catheter Ablation in Persistent Atrial Fibrillation and Left Ventricular Systolic Dysfunction.

BACKGROUND: The optimal timing of catheter ablation in individuals with atrial fibrillation (AF) and left ventricular systolic dysfunction (LVSD) remains uncertain. OBJECTIVE: We examined whether AF diagnosis to ablation time (DAT) influences outcomes following catheter ablation(CA) in patients with persistent AF (PsAF) and LVSD from the CAMERA MRI and CAPLA randomized studies. METHODS: We evaluated clinical outcomes according to DAT <1 year ("shorter DAT") and >1 year ("longer DAT"), comparing AF recurrence, AF burden, left ventricular ejection fraction (LVEF) and LV recovery (LVEF>50%) at 12 months. DAT was also compared according to the median (24 months). RESULTS: 210 individuals with AF and LVSD were identified, with a median DAT of 24 months. Shorter DAT was associated with lower LA global and posterior wall scar (<0.05mV; both p<0.05). At 12 months, 69.4% with shorter DAT (<1year) were free from recurrent atrial arrhythmias vs 53.6% in longer DAT (HR 1.63, 95% CI 1.01-2.65 p=0.040). Median AF burden was 0% in both groups (shorter DAT:IQR 0.0-2.0% vs longer DAT:IQR 0.0-7.3%,p=0.017). At 12 months, shorter DAT was associated with higher LVEF (55.3% vs 51.0%, p=0.009), greater LVEF improvement (+20.8±13.0% vs +13.9±13.2% longer DAT, p<0.001) and LV recovery (75.0% vs longer DAT: 57.2%, p=0.011). Shorter DAT was associated with fewer hospitalisations and electrical cardioversions at 12 months. CONCLUSIONS: In individuals with AF and LVSD, shorter DAT was associated with greater LVEF improvement and arrhythmia-free survival with lower AF burden and rehospitalization at 12 months, highlighting the prognostic benefit of early CA in AF and LVSD.