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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/m 2 age ≥ 65, p = .834; indexed left ventricular end-diastolic volume: 108 ± 40 vs. 104 ± 28 mL/m 2 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 CHADS 2 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., (© 2023 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

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., (© 2021 Wiley Periodicals LLC.)

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., (© 2020 Wiley Periodicals LLC.)

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., (© 2018 Wiley Periodicals, Inc.)

Introduction: The right atrium (RA) is readily accessible; however, it is unclear whether changes in the RA are representative of the LA. We performed detailed biatrial electroanatomic mapping to determine the electrophysiological relationship between the atria., Methods and Results: Consecutive patients with persistent AF underwent biatrial electroanatomical mapping with a contact force catheter acquiring points with a CF >10 g prior to ablation. Points were analyzed for tissue voltage, complex electrograms, low voltage (<0.5 mV), scar (<0.05 mV), and conduction velocity (CV). Forty patients (mean age 59 ± 9.2 years, AF duration 12.9 ± 9.2 months, LA area: 28 ± 5.2, RA area: 25 ± 6.4 mm 2 , LVEF: 44 ± 15%) underwent mapping during CS pacing. Bipolar voltage (R = 0.57, P <0.001), unipolar voltage (R = 0.68, P <0.001), low voltage (<0.5 nV) (R = 0.48, P = 0.002), fractionation (R = 0.73, P <0.001), and CV (R = 0.49, P = 0.001) correlated well between atria. There was no difference in global bipolar voltage (LA 1.89 ± 0.77 vs. RA 1.77 ± 0.57 mV, P = 0.57); complex electrograms (LA 20% vs. RA 20%, P = 0.99) or low voltage (LA 15% vs. RA 16%, P = 0.84). Global unipolar voltage was significantly higher in the LA compared to the RA (2.95 ± 1.14 vs. 2.28 ± 0.65 mV, P = 0.002) and CV was significantly slower in the RA compared to the LA (0.93 ± 0.15 m/s vs. 1.01 ± 0.19 m/s, P = 0.001)., Conclusion: AF is associated with remodeling processes affecting both atria. The more accessible RA provides an insight into the biatrial process associated with AF in various disease states without trans-septal access., (© 2017 Wiley Periodicals, Inc.)

Introduction: ELECTROPHYSIOLOGICAL AND HEMODYNAMIC ASSESSMENT., Dormant-Af Study: The significance of adenosine induced dormant pulmonary vein (PV) conduction in atrial fibrillation (AF) ablation remains controversial. The optimal dose of adenosine to determine dormant PV conduction is yet to be systematically explored., Methods and Results: ELECTROPHYSIOLOGICAL AND HEMODYNAMIC ASSESSMENT., Dormant-Af Study: Consecutive patients undergoing index AF ablation received 3 adenosine doses (12, 18, and 24 mg) in a randomized blinded order, immediately after pulmonary vein isolation (PVI). Electrophysiological (PR prolongation, AV block (AVB) and PV reconnection) and hemodynamic (BP) parameters were measured. A total, 339 doses (113/dose) assessed 191 PVs in 50 patients (66% male, 72% PAF, 52% hypertensive). Dormant PV conduction occurred in 28% of patients (16.5% [32] of PVs). All cases were associated with AVB (AVB: PV reconnection vs. no PV reconnection 100% vs. 83%, P = 0.007). AVB occurred more frequently at 24 mg versus 12 mg (92% vs. 82%, P = 0.019) but not versus 18 mg (91%, P = 0.62). AVB duration progressed between 12 mg (12.0 ± 8.9 seconds), 18 mg (16.1 ± 9.1 seconds, P = 0.001), and 24 mg (19.0 ± 9.3 seconds, P < 0.001) doses. MBP fell further at 24 mg (ΔMBP: 27 ± 12 mmHg) and 18 mg (26 ± 13 mmHg) doses compared to 12 mg (22 ± 10 mmHg vs., P < 0.001). A significant reduction in AVB in patients >110 kg (65% vs. 91% in 70-110 kg group, P < 0.001) in response to adenosine was seen., Conclusion: ELECTROPHYSIOLOGICAL AND HEMODYNAMIC ASSESSMENT., Dormant-Af Study: An adenosine dose producing AVB is required to unmask dormant PV conduction. AVB is significantly reduced in patients >110 kg. Weight and dosing variability may in part explain the conflicting results of studies evaluating the clinical utility of adenosine in PVI., (© 2016 Wiley Periodicals, Inc.)

Introduction: Non-sustained ventricular tachycardia (NSVT) is a risk factor for sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM). We aimed to assess whether diffuse ventricular fibrosis on cardiac magnetic resonance (CMR) imaging could be a surrogate marker for ventricular arrhythmias in patients with HCM., Methods: A total of 100 patients with HCM (mean age 51 ± 13 years, septal wall thickness 20 ± 5 mm) underwent CMR with a 1.5 T scanner to determine the presence of ventricular late gadolinium enhancement (LGE) for focal fibrosis, and post-contrast T1 mapping for diffuse ventricular fibrosis. The presence of NSVT was determined by Holter monitoring and a subset of high risk patients received an implantable cardioverter-defibrillator (ICD)., Results: NSVT was detected in 23 of 100 patients with HCM. Focal ventricular fibrosis (by LGE) was observed in 87%, with no significant difference between patients with (96%) or without NSVT (86%, P = 0.19). However, LGE mass was greater in patients with (16.5 ± 19.1 g) versus without NSVT (7.6 ± 10.2 g, P < 0.01). NSVT was associated with a significant reduction in ventricular T1 relaxation time (422 ± 54 milliseconds) versus patients without NSVT (512 ± 115 milliseconds; P < 0.001). There was significant reduction in ventricular T1 relaxation time in patients with (430 ± 48 milliseconds) versus without aborted SCD (495 ± 113 milliseconds; P = 0.01) over a mean follow-up of 40 ± 10 months. On multivariate analysis post-contrast ventricular T1 relaxation time and septal wall thickness were the only predictors of NSVT., Conclusion: Post-contrast T1 relaxation time on CMR is associated with ventricular arrhythmias in patients with HCM. Diffuse ventricular fibrosis may be an important marker of arrhythmic risk in patients with HCM., (© 2016 Wiley Periodicals, Inc.)

Background: Catheter ablation for AF is an effective treatment for patients with AF and systolic LV dysfunction; however, the clinical outcome is variable. We evaluated the impact of cardiomyopathy etiology on long-term outcomes post-catheter ablation., Methods: Patients undergoing AF ablation across 3 centers (2 Australian, 1 UK) from 2002 to 2014, with LVEF<45% were evaluated. Patients were stratified into those with known heart disease as a cause of cardiomyopathy (KHD), and those with idiopathic dilated cardiomyopathy (IDCM)., Results: One hundred and one patients (IDCM = 77, KHD = 24) with AF and LVEF <45% underwent AF ablation. The KHD group (ischemic HD in 67%) were older (61 ± 7 vs. 55 ± 11 years, P = 0.005), with a higher CHADS2 score (2.0 ± 0.8 vs. 1.6 ± 0.7, P = 0.016), but otherwise well matched. After mean follow-up of 36 ± 23 months, AF control was greater in the IDCM group (82% vs. 50% in KHD, P < 0.001). On multivariate analysis IDCM was associated with long-term AF control (P = 0.033). The IDCM group had less functional impairment at follow-up (NYHA class 1.5 ± 0.7 vs. 2.0 ± 0.8, P = 0.005) and improved LVEF (50 ± 11% vs. 38 ± 10%, P < 0.001). Super responders (EF improvement >15%) were overwhelmingly in the IDCM group (94% vs. 6%, P < 0.001) with greater AF control (89% vs. 61%, P < 0.001). All-cause mortality was significantly higher in the KHD group (17% vs. 1.3%, P = 0.002)., Conclusion: IDCM was associated with greater AF control, and improvement in symptoms and LVEF compared to patients with KHD post-AF ablation. AF is an important reversible cause of HF in patients with an unexplained CM and catheter ablation an effective treatment option., (© 2015 Wiley Periodicals, Inc.)

Introduction: The transesophageal echo probe (TEE) is commonly used before and during atrial fibrillation (AF) ablation under general anesthesia (GA). We sought to determine the potential contribution of the TEE probe to esophageal injury after pulmonary vein isolation (PVI) alone for paroxysmal AF., Methods and Results: Seventy-six patients undergoing PVI with TEE, PVI/TEE, 16 undergoing PVI without TEE (PVI/No TEE), and 27 undergoing TEE without any left atrial ablation (TEE/No LA ablation) under GA were included. Posterior wall ablation was power (20-25 W) and time limited (electrogram attenuation or ≤30 s). Esophageal capsule endoscopy (n = 206) was performed pre- and post-procedure and at 2 weeks. Esophageal lesions were seen in 30% of PVI/TEE, 0% of patients in the PVI/No TEE (P = 0.009), and 22% of TEE/No LA ablation groups (P = 0.47 vs. PVI/TEE). There were no instances of esophageal bleeding, perforation, or need for gastrointestinal intervention. Self-resolving dysphagia was the only reported symptom (5%). All lesions healed within 2 weeks. There was no significant difference in the location or morphological appearance of esophageal lesions seen in the PVI/TEE versus TEE/No LA ablation groups., Conclusions: Esophageal lesions were seen in 30% of patients undergoing PVI alone under GA with use of TEE and in a similar proportion (22%) of patients undergoing TEE in the absence of left atrial ablation. This study makes the preliminary observation that one must be cognizant of the TEE probe as a potential contributor to esophageal injury after AF ablation. Larger studies are needed to confirm these findings., (© 2014 Wiley Periodicals, Inc.)

Introduction: Pulmonary vein reconnection is a major limitation of pulmonary vein isolation (PVI) for symptomatic atrial fibrillation (AF). Adenosine may unmask dormant PV conduction and facilitate consolidation of PV isolation. We performed a systematic review of the literature to determine the impact of routine adenosine administration on clinical outcomes in patients undergoing PVI., Methods: References and electronic databases reporting AF ablation and adenosine following PVI were searched through to 31 July 2012. Six studies included 544 patients to assess the impact of catheter ablation to target adenosine-induced PV reconnection on AF ablation outcome and 3 studies included 612 patients to assess the impact of adenosine testing on AF ablation outcome. Relative risks were calculated and combined in a meta-analysis using random effects modeling., Results: Routine adenosine testing for PV reconnection with additional targeted ablation resulted in a significant increase in freedom from AF post-PVI (RR 1.25; 95% CI 1.12-1.40; P < 0.001). However, within the group of patients undergoing adenosine testing, those with reconnection identified a population with a trend to reduction in freedom from AF despite the use of further targeted ablation in the reconnection group (RR 0.91 with 95% CI 0.81-1.03; P = 0.15)., Conclusion: Routine adenosine testing is associated with an improvement in freedom from AF post-PVI. Paradoxically acute adenosine-induced PV reconnection may portend a greater likelihood of AF recurrence despite additional ablation. Randomized controlled trials are required to determine the role of adenosine testing post-PVI., (© 2013 Wiley Periodicals, Inc.)