Diagnosis to Ablation in Persistent AF: Any Time Can Be a Good Time to Ablate.

BACKGROUND: Nonrandomized data suggest that longer diagnosis-to-ablation time (DAT) is associated with poorer outcomes; however, a recent randomized trial found no difference in recurrences when ablation was delayed by 12 months. OBJECTIVES: This study sought to assess the impact of DAT on atrial fibrillation (AF) recurrence in patients undergoing catheter ablation for persistent AF. METHODS: 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: The CAPLA randomized clinical trial) was a multicenter trial that randomized patients with persistent AF to pulmonary vein isolation + posterior wall isolation or pulmonary vein isolation alone. Follow-up was 12 months. Outcomes were assessed after a 3-month blanking period. RESULTS: Median DAT in the 334 patients was 28 months (Q1-Q3: 12-66 months). Patients were divided into quartile groups: Q1 was DAT 0 to 12 months (n = 84, median DAT 7 months), Q2 was DAT 13 to 28 months (n = 85, median DAT 20 months), Q3 was DAT 29 to 66 months (n = 84, median DAT 41 months), and Q4 was DAT ≥67 months (n = 81, median DAT 119 months). AF recurrence rate was 36.9% for Q1, 44.7% for Q2, 47.6% for Q3, and 56.8% for Q4 (P = 0.082). On multivariable analysis, DAT Q4 was the only factor significantly associated with risk of recurrence (HR: 1.607; 95% CI: 1.005-2.570; P = 0.048). Median AF burden was 0% (Q1-Q3: 0%-0.47%) in Q1 and 0.33% (Q1-Q3: 0%-4.6%) in Q4 (P = 0.002). Quality of life (assessed by the Atrial Fibrillation Effect on Quality-of-Life questionnaire) improved markedly in all quartiles (Q1: Δ28.8 ± 24, Q2: Δ24.4 ± 23.4, Q3: Δ21.7 ± 26.6, Q4: Δ24.6 ± 21.4; P = 0.331). CONCLUSIONS: In a cohort of patients with persistent AF undergoing ablation in a prospective trial with standardized entry criteria and intensive electrocardiogram monitoring, those with shorter DAT had lower rates of AF recurrence. However, differences were modest, and all quartiles demonstrated very low AF burden and improvements in quality of life.

Predictors of Late Atrial Fibrillation Recurrence After Cardiac Surgery.

BACKGROUND: Although postoperative atrial fibrillation (POAF) frequently occurs early after cardiac surgery, there is a paucity of data evaluating predictors and timing of late atrial fibrillation (AF) recurrence. OBJECTIVES: The authors sought to evaluate predictors of late AF recurrence in patients undergoing cardiac surgery. METHODS: We retrospectively reviewed cardiac surgery patients from 2010 to 2018 with no preoperative diagnosis of AF or atrial flutter. We recorded incidence and timing of late AF recurrence, defined as occurring ≥12 months following surgery. RESULTS: 1,031 patients were included (mean age at surgery 64 ± 12 years, 74% male). Early POAF was recorded in 445 patients (43%). POAF was usually transient, with total AF duration <48 hours in 72% and reversion to sinus rhythm at discharge in 91%. At 4.7 ± 2.4 years follow-up, late AF occurred in 139 patients (14%). Median time to AF recurrence was 4.4 years post-surgery (Q1-Q3: 2.6-6.2 years). Late AF was significantly more likely among patients with early POAF than those without (23% vs 6%; P < 0.001), with highest incidence (38%) in those with POAF duration >48 hours. In a multivariable analysis, early POAF duration >48 hours was a significant predictor of late AF recurrence (HR: 5.9). Surgery type and CHA2DS2-VASc score were not predictive of late AF events. CONCLUSIONS: Post-operative AF episodes of duration ≥48 hours predict recurrent AF episodes over long-term follow-up after cardiac surgery. Implications for arrhythmia surveillance and anticoagulation in patients with longer duration POAF episodes require further study.

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.

Lifelong physiology of a former marathon world-record holder - the pros and cons of extreme cardiac remodeling.

In a 77-year-old former world-record holding male marathoner (2:08:33.6) this study sought to investigate the impact of lifelong intensive endurance exercise on cardiac structure, function and the trajectory of functional capacity (determined by maximal oxygen consumption, V̇O2max) throughout the adult lifespan. As a competitive runner, our athlete (DC) reported performing up to 150-300 miles/wk of moderate-to-vigorous exercise, and sustained 10-15 hours/wk of endurance exercise after retirement from competition. DC underwent maximal cardiopulmonary exercise testing in 1970 (aged 27yrs), 1991 (aged 49yrs) and 2020 (aged 77yrs) to determine V̇O2max. At his evaluation in 2020, DC also underwent comprehensive cardiac assessments including resting echocardiography, and resting and exercise cardiac magnetic resonance to quantify cardiac structure and function at rest and during peak supine exercise. DC's V̇O2max showed minimal change from 27yrs (69.7mL/kg/min) to 49yrs (68.1mL/kg/min), although it eventually declined by 36% by the age of 77yrs (43.6mL/kg/min). DC's V̇O2max at 77yrs, was equivalent to the 50th percentile for healthy 20-29 year-old males and 2.4 times the requirement for maintaining functional independence. This was partly due to marked ventricular dilatation (left-ventricular end-diastolic volume: 273mLs), which facilitates a large peak supine exercise stroke volume (200mLs) and cardiac output (22.2L/min). However, at the age of 78 years, DC developed palpitations and fatigue, and was found to be in atrial fibrillation requiring ablation procedures to revert his heart to sinus rhythm. Overall, this life study of a world champion marathon runner exemplifies the substantial benefits and potential side effects of many decades of intense endurance exercise.

Pulmonary Veins Function as Echo Chambers in Persistent Atrial Fibrillation: Circuitous Re-Entry Generates Outgoing Wavefronts.

BACKGROUND: Although the substrate in persistent atrial fibrillation (PeAF) is not limited to the pulmonary veins (PVs), PV isolation (PVI) remains the cornerstone ablation strategy. OBJECTIVES: The aim of this study was to describe the mechanism of outgoing wavefronts (WFs) originating in the PV sleeves during PeAF. METHODS: Eleven patients presenting for first-time PeAF ablation were recruited (mean age 63.1 ± 10.9 years, 91% men). A 64-electrode catheter (Constellation; 38 mm) was positioned within the PV under fluoroscopic guidance. An inverse mapping technique was used to reconstruct unipolar atrial electrograms on the PV surface, and the resulting phase maps were used to identify incoming and outgoing WFs at the PV junction and to classify focal and re-entrant activity within the PV sleeves. RESULTS: During PeAF, the PVs gave rise to outgoing WFs with a frequency of 3.7 s-1 (Q1-Q3: 3.4-5.4 s-1) compared with 3.6 s-1 (Q1-Q3: 2.8-4.2 s-1) for incoming WFs. Circuitous macroscopic re-entry was the dominant mechanism driving outgoing WFs (frequency of re-entry 2.7 s-1 [Q1-Q3: 2.0-3.3 s-1] compared with focal activity 1.4 s-1 [Q1-Q3: 1.1-1.5 s-1]; P < 0.006). This was initiated by incoming WFs in 80% of cases. Consecutive focal activation from the same location was infrequent (10.0% ± 6.6%, n = 10). Rotors ≥360° were never observed. The median ratio (R) of outgoing to incoming WF frequency was 1.14 (Q1-Q3: 0.84-1.75), with R > 1 in 6 of 11 PVs. CONCLUSIONS: Electric activity generated by PV sleeves during PeAF is due mainly to circuitous re-entry initiated by incoming waves, frequently with R > 1. That is, the PVs act less as drivers of atrial fibrillation than as "echo chambers" that sustain and amplify fibrillatory activity.

2023 Cardiac Society of Australia and New Zealand Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation.

Catheter ablation for atrial fibrillation (AF) has increased exponentially in many developed countries, including Australia and New Zealand. This Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation from the Cardiac Society of Australia and New Zealand (CSANZ) recognises healthcare factors, expertise and expenditure relevant to the Australian and New Zealand healthcare environments including considerations of potential implications for First Nations Peoples. The statement is cognisant of international advice but tailored to local conditions and populations, and is intended to be used by electrophysiologists, cardiologists and general physicians across all disciplines caring for patients with AF. They are also intended to provide guidance to healthcare facilities seeking to establish or maintain catheter ablation for AF.

Impact of Posterior Wall Isolation During AF Ablation on the Incidence of Left Atrial Flutter.

BACKGROUND: Linear and complex electrogram ablation (LCEA) beyond pulmonary vein isolation (PVI) is associated with an increase in left atrial macro-re-entrant tachycardias (LAMTs). Posterior wall isolation (PWI) is increasingly performed to improve AF ablation outcomes. However, the impact of PWI on the incidence of LAMT is unknown. OBJECTIVES: The purpose of this study was to establish the incidence of LAMT following PVI alone vs PVI + PWI vs PVI + PWI + LCEA. METHODS: Consecutive patients undergoing catheter ablation for AF or LAMT post-AF ablation between 2008 and 2022 from 4 electrophysiology centers were reviewed with a minimum follow-up of 12 months. RESULTS: In total, 5,619 (4,419 index, 1,100 redo) AF ablation procedures were performed in 4,783 patients (mean age 60.9 ± 10.6 years, 70.7% men). Over a mean follow-up of 6.4 ± 3.8 years, 246 procedures for LAMT were performed in 214 patients at a mean of 2.6 ± 0.6 years post-AF ablation. Perimitral (52.8% of patients), roof-dependent (27.1%), PV gap-related (17.3%), and anterior circuits (8.9%) were most common, with 16.4% demonstrating multiple circuits. The incidence of LAMT was significantly higher following PVI + PWI (6.2%) vs PVI alone (3.0%; P < 0.0001) and following PVI + PWI + LCEA vs PVI + PWI (12.5%; P = 0.019). Conduction gaps in previous ablation lines were responsible for LAMT in 28.4% post-PVI alone, 35.3% post-PVI + PWI (P = 0.386), and 81.8% post-PVI + PWI + LCEA (P < 0.005). CONCLUSIONS: The incidence of LAMT following PVI + PWI is higher than with PVI alone but significantly lower than with more extensive atrial substrate modification. Given a low frequency of LAMT following PWI, empiric mitral isthmus ablation is not justified and may be proarrhythmic.

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.

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.

Sex-specific outcomes after catheter ablation for persistent AF.

BACKGROUND: 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-nine women (23.4%; PVI 37; PVI + PWI 42) and 259 men (76.6%; PVI 131; PVI + PWI 128) underwent AF ablation. Women were 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 = .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 = .711). The median AF burden was 0% in both groups (women: IQR 0.0%-2.2% vs men: IQR 0.0%-2.8%; P = .804). Health care utilization was comparable between women (36.7%) and men (30.1%) (P = .241); however, women were more likely to undergo a repeat procedure (17.7% vs 6.9%; P = .007). Women reported more severe baseline anxiety (average Hospital Anxiety and Depression Scale [HADS] anxiety score 7.5 ± 4.9 vs 6.3 ± 4.3 in men; P = .035) and AF-related symptoms (baseline Atrial Fibrillation Effect on Quality-of-Life Questionnaire [AFEQT] score 46.7 ± 20.7 vs 55.9 ± 23.0 in men; P = .002), with comparable improvements in psychological symptoms (change in HADS anxiety score -3.8 ± 4.6 vs -3.0 ± 4.5; P = .152 (change in HADS depression score -2.9 ± 5.0 vs -2.6 ± 4.0; P = .542) and greater improvement in AFEQT score compared with men at 12 months (change in AFEQT score +45.9 ± 23.1 vs +39.2 ± 24.8; P = .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.

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.

P-Wave Morphology From Common Nonpulmonary Vein Trigger Sites Following Pulmonary Vein and Posterior Wall Isolation.

BACKGROUND: Non-pulmonary vein (PV) triggers are increasingly targeted during atrial fibrillation (AF) ablation. P-wave morphology (PWM) can be useful because point mapping of AF triggers is challenging. The impact of prior ablation on PWM is yet to be determined. OBJECTIVES: This study sought to report PWM before and after left atrial (LA) ablation and construct a P-wave algorithm of common non-PV trigger locations. METHODS: This multicenter, prospective, observational study analyzed the paced PWM of 30 patients with persistent AF undergoing pulmonary vein isolation (PVI) and posterior wall isolation (PWI). Pace mapping was performed at the SVC, crista terminalis, inferior tricuspid annulus, coronary sinus ostium, left septum, left atrial appendage, Ligament of Marshall, and inferoposterior LA. The PWM was reported before PVI, then blinded comparisons were made post-PVI and post-PVI + PWI. A P-wave algorithm was constructed. RESULTS: A total of 8,352 paced P waves were prospectively recorded. No significant changes in the PWM were seen post-PVI alone in 2,775 of 2,784 (99.7%) and post-PWI in 2,715 of 2,784 (97.5%). Changes in PWM were predominantly at the IPLA (53 P waves) with a positive P-wave in leads V2 to V6 before biphasic post-PWI, LA appendage (9 P waves), coronary sinus ostium (6 P waves), and ligament of Marshall (3 P waves). A PWM algorithm was created before PVI and accurately predicted the location in 93% post-PVI + PWI. CONCLUSIONS: Minimal change was observed in PWM post-PV and PWI aside from the IPLA location. A P-wave algorithm created before and applied after PVI + PWI provided an accuracy of 93%. PWM provides a reliable tool to guide the localization of common non-PV trigger sites even after PV and PWI.

Optimal Annotation of Local Activation Time in Ventricular Tachycardia Substrate Mapping.

BACKGROUND: Accurate annotation of electrogram local activation time (LAT) is critical to the functional assessment of ventricular tachycardia (VT) substrate. Contemporary methods of annotation include: 1) earliest bipolar electrogram (LATearliest); 2) peak bipolar electrogram (LATpeak); 3) latest bipolar electrogram (LATlatest); and 4) steepest unipolar -dV/dt (LAT-dV/dt). However, no direct comparison of these methods has been performed in a large dataset, and it is unclear which provides the optimal functional analysis of the VT substrate. OBJECTIVES: This study sought to investigate the optimal method of LAT annotation during VT substrate mapping. METHODS: Patients with high-density VT substrate maps and a defined critical site for VT re-entry were included. All electrograms were annotated using 5 different methods: LATearliest, LATpeak, LATlatest, LAT-dV/dt, and the novel steepest unipolar -dV/dt using a dynamic window of interest (LATDWOI). Electrograms were also tagged as either late potentials and/or fractionated signals. Maps, utilizing each annotation method, were then compared in their ability to identify critical sites using deceleration zones. RESULTS: Fifty cases were identified with 1,.813 ± 811 points per map. Using LATlatest, a deceleration zone was present at the critical site in 100% of cases. There was no significant difference with LATearliest (100%) or LATpeak (100%). However, this number decreased to 54% using LAT-dV/dt and 76% for LATDWOI. Using LAT-dV/dt, only 33% of late potentials were correctly annotated, with the larger far field signals often annotated preferentially. CONCLUSIONS: Annotation with LAT-dV/dt and LATDWOI are suboptimal in VT substrate mapping. We propose that LATlatest should be the gold standard annotation method, as this allows identification of critical sites and is most suited to automation.

Transvenous versus subcutaneous implantable cardioverter defibrillators in young cardiac arrest survivors.

Secondary prevention implantable cardioverter defibrillators (ICDs) are indicated in young patients presenting with aborted sudden cardiac death (SCD) because of ventricular arrhythmias. Transvenous-ICDs (TV-ICDs) are effective, established therapies supported by evidence. The significant morbidity associated with transvenous leads led to the development of the newer subcutaneous-ICD (S-ICD). This review discusses the clinical considerations when selecting an ICD for the young patient presenting with out-of-hospital cardiac arrest. The major benefits of TV-ICDs are their ability to pace (antitachycardia pacing [ATP], bradycardia support and cardiac resynchronisation therapy [CRT]) and the robust evidence base supporting their use. Other benefits include a longer battery life. Significant complications associated with transvenous leads include pneumothorax and tamponade during insertion and infection and lead failure in the long term. Comparatively, S-ICDs, by virtue of having no intravascular leads, prevent these complications. S-ICDs have been associated with a higher incidence of inappropriate shocks. Patients with an indication for bradycardia pacing, CRT or ATP (documented ventricular tachycardia) are seen as unsuitable for a S-ICD. If venous access is unsuitable or undesirable, S-ICDs should be considered given the patient is appropriately screened. There is a need for further randomised controlled trials to directly compare the two devices. TV-ICDs are an effective therapy for preventing SCD limited by significant lead-related complications. S-ICDs are an important development hindered largely by an inability to pace. Young patients stand to gain the most from a S-ICD as the cumulative risk of lead-related complications is high. A clinical framework to aid decision-making is presented.

The Role of Posterior Wall Isolation in Catheter Ablation for Persistent Atrial Fibrillation and Systolic Heart Failure: A Secondary Analysis of a Randomized Clinical Trial.

Importance: Catheter ablation for patients with atrial fibrillation (AF) and heart failure with reduced ejection fraction (HFrEF) is associated with improved left ventricular ejection fraction (LVEF) and survival compared with medical therapy. Nonrandomized studies have reported improved success with posterior wall isolation (PWI). Objective: To determine the impact of pulmonary vein isolation (PVI) with PWI vs PVI alone on outcomes in patients with HFrEF. Design, Setting, and Participants: This was an ad hoc secondary analysis of the CAPLA trial, a multicenter, prospective, randomized control trial that involved 11 centers in 3 countries (Australia, Canada, and UK). CAPLA featured 338 patients with persistent AF randomized to either PVI plusPWI or PVI alone. This substudy included patients in the original CAPLA study who had symptomatic HFrEF (LVEF <50% and New York Heart Association class ≥II). Interventions: Pulmonary vein isolation with PWI vs PVI alone. Main Outcomes and Measures: The primary end point was freedom from any documented atrial arrhythmia greater than 30 seconds, after a single ablation procedure, without the use of antiarrhythmic drug (AAD) therapy at 12 months. Results: A total of 98 patients with persistent AF and symptomatic HFrEF were identified (mean [SD] age, 62.1 [9.8] years; 79.5% men; and mean [SD] LVEF at baseline, 34.6% [7.9%]). After 12 months, 58.7% of patients with PVI plus PWI were free from recurrent atrial arrhythmia without the use of AAD therapy vs 61.5% with PVI alone (hazard ratio, 1.02; 95% CI, 0.54-1.91; P = .96). There were no significant differences in freedom from atrial arrhythmia with or without AAD therapy after multiple procedures (PVI plus PWI vs PVI alone, 60.9% vs 65.4%; P = .73) or AF burden (median, 0% in both groups; P = .78). Mean LVEF improved substantially in PVI plus PWI (∆ LVEF, 19.3% [13.0%; P < .01) and PVI alone (18.2% [14.1%; P < .01), with no difference between groups (P = .71). Normalization of LV function occurred in 65.2% of patients in the PVI plus PWI group and 50.0% of patients with PVI alone (P = .13). Conclusions and Relevance: The results of this study indicate that addition of PWI to PVI did not improve freedom from arrhythmia recurrence or recovery of LVEF in patients with persistent AF and symptomatic HFrEF. Catheter ablation was associated with significant improvements in systolic function, irrespective of ablation strategy used. These results caution against the routine inclusion of PWI in patients with HFrEF undergoing first-time catheter ablation for persistent AF. Trial Registration: http://anzctr.org.au Identifier: ACTRN12616001436460.

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.