Impact of Posterior Left Atrial Voltage on Ablation Outcomes in Persistent Atrial Fibrillation: CAPLA Substudy

BACKGROUND

Pulmonary vein isolation (PVI) is less effective in patients with persistent atrial fibrillation (PsAF). Adjunctive ablation targeting low voltage areas (LVAs) may improve arrhythmia outcomes.

OBJECTIVES

This study aims to compare the outcomes of adding posterior wall isolation (PWI) to PVI, vs PVI alone in PsAF patients with posterior wall LVAs.

METHODS

The CAPLA (Effect of Catheter Ablation Using Pulmonary Vein Isolation With vs Without Posterior Left Atrial Wall Isolation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation) study was a multicenter, randomized trial involving PsAF patients randomized 1:1 to either PVI alone or PVI with PWI. Voltage mapping performed during pacing pre-ablation was reviewed offline, with LVA defined as bipolar voltage of <0.5 mV. The primary endpoint was freedom from any documented atrial arrhythmia of >30 seconds off antiarrhythmic medication at 12 months after a single ablation procedure in patients with posterior LVA.

RESULTS

A total of 210 patients (average 64.6 ± 9.2 years,73.3% males, median atrial fibrillation duration 4.5 months [IQR: 2 to 8 months]) underwent multipolar left atrial mapping during coronary sinus pacing with posterior LVA present in 69 (32.9%). Patients with posterior LVA were more likely to have LVA in other atrial regions (91.7% vs 57.1%; P < 0.01), larger left atrial diameter (4.8 cm vs 4.4 cm; P < 0.01), and significantly increased risk of atrial arrhythmia recurrence at 12 months (LVA: 56.5% vs no LVA: 41.4%; HR: 1.51; 95% CI: 1.01-2.27; P = 0.04) compared to no posterior LVA. However, the addition of PWI to PVI did not significantly improve freedom from atrial arrhythmia recurrence over PVI alone (PVI with PWI: 44.8% vs PVI: 41.9%; HR: 0.95; 95% CI: 0.51-1.79; P = 0.95).

CONCLUSIONS

In patients with PsAF undergoing catheter ablation, posterior LVA was associated with a significant increase in atrial arrhythmia recurrence. However, the addition of PWI in those with posterior LVA did not reduce atrial arrhythmia recurrence over PVI alone.

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.

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.

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.

Polymorphic Ventricular Tachycardia Storm After Coronary Artery Bypass Graft Surgery: A Form of 'Angry Purkinje Syndrome'

BACKGROUND

Polymorphic ventricular tachycardia (PMVT) is a highly lethal arrhythmia which is commonly caused by acute myocardial ischaemia. PMVT mediated by short-coupled ventricular ectopy patients with ischaemic heart disease but in the absence of acute ischaemia may relate to transient peri-infarct Purkinje fibre irritability and has been termed 'Angry Purkinje Syndrome'.

METHODS

We present a case series of three patients with PMVT storm 3-5 days following coronary artery bypass graft surgery (CABG). In all three cases, recurrent episodes of PMVT were initiated by monomorphic ventricular ectopy with a short coupling interval. Acute coronary ischaemia was excluded in all three patients with a coronary angiogram and graft study. Two out of three of the patients commenced oral quinidine sulphate with subsequent rapid suppression of arrhythmia. Implantable cardiac defibrillators were implanted in all three patients and revealed no recurrence of PMVT following hospital discharge.

CONCLUSION

The Angry Purkinje Syndrome is a rare but important cause of ventricular tachycardia storm after CABG surgery and is mediated by short-coupled ventricular ectopy in the absence of acute myocardial ischaemia. This arrhythmia may be highly responsive to quinidine.

Identifying Patients at High Risk of Left Atrial Appendage Thrombus Before Cardioversion: The CLOTS-AF Score

Background Transesophageal echocardiography-guided direct cardioversion is recommended in patients who are inadequately anticoagulated due to perceived risk of left atrial appendage thrombus (LAAT); however, LAAT risk factors remain poorly defined. Methods and Results We evaluated clinical and transthoracic echocardiographic parameters to predict LAAT risk in consecutive patients with atrial fibrillation (AF)/atrial flutter undergoing transesophageal echocardiography before cardioversion between 2002 and 2022. Regression analysis identified predictors of LAAT, combined to create the novel CLOTS-AF risk score (comprising clinical and echocardiographic LAAT predictors), which was developed in the derivation cohort (70%) and validated in the remaining 30%. A total of 1001 patients (mean age, 62±13 years; 25% women; left ventricular ejection fraction, 49.8±14%) underwent transesophageal echocardiography, with LAAT identified in 140 of 1001 patients (14%) and dense spontaneous echo contrast precluding cardioversion in a further 75 patients (7.5%). AF duration, AF rhythm, creatinine, stroke, diabetes, and echocardiographic parameters were univariate LAAT predictors; age, female sex, body mass index, anticoagulant type, and duration were not (all P>0.05). CHADS2VASc, though significant on univariate analysis (P<0.001), was not significant after adjustment (P=0.12). The novel CLOTS-AF risk model comprised significant multivariable predictors categorized and weighted according to clinically relevant thresholds (Creatinine >1.5 mg/dL, Left ventricular ejection fraction <50%, Overload (left atrial volume index >34 mL/m2), Tricuspid Annular Plane Systolic Excursion (TAPSE) <17 mm, Stroke, and AF rhythm). The unweighted risk model had excellent predictive performance with an area under the curve of 0.820 (95% CI, 0.752-0.887). The weighted CLOTS-AF risk score maintained good predictive performance (AUC, 0.780) with an accuracy of 72%. Conclusions The incidence of LAAT or dense spontaneous echo contrast precluding cardioversion in patients with AF who are inadequately anticoagulated is 21%. Clinical and noninvasive echocardiographic parameters may identify patients at increased risk of LAAT better managed with a suitable period of anticoagulation before undertaking cardioversion.

Atrial Fibrillation Ablation for Heart Failure With Preserved Ejection Fraction: A Randomized Controlled Trial

BACKGROUND

Patients with heart failure with preserved ejection fraction (HFpEF) frequently develop atrial fibrillation (AF). There are no randomized trials examining the effects of AF ablation on HFpEF outcomes.

OBJECTIVES

The aim of this study is to compare the effects of AF ablation vs usual medical therapy on markers of HFpEF severity, including exercise hemodynamics, natriuretic peptide levels, and patient symptoms.

METHODS

Patients with concomitant AF and HFpEF underwent exercise right heart catheterization and cardiopulmonary exercise testing. HFpEF was confirmed with pulmonary capillary wedge pressure (PCWP) of 15 mm Hg at rest or ≥25 mm Hg on exercise. Patients were randomized to AF ablation vs medical therapy, with investigations repeated at 6 months. The primary outcome was change in peak exercise PCWP on follow-up.

RESULTS

A total of 31 patients (mean age: 66.1 years; 51.6% females, 80.6% persistent AF) were randomized to AF ablation (n = 16) vs medical therapy (n = 15). Baseline characteristics were comparable across both groups. At 6 months, ablation reduced the primary outcome of peak PCWP from baseline (30.4 ± 4.2 to 25.4 ± 4.5 mm Hg; P < 0.01). Improvements were also seen in peak relative VO2 (20.2 ± 5.9 to 23.1 ± 7.2 mL/kg/min; P < 0.01), N-terminal pro-B-type natriuretic peptide levels (794 ± 698 to 141 ± 60 ng/L; P = 0.04), and MLHF (Minnesota Living with Heart Failure) score (51 ± -21.9 to 16.6 ± 17.5; P < 0.01). No differences were detected in the medical arm. Following ablation, 50% no longer met exercise right heart catheterization-based criteria for HFpEF vs 7% in the medical arm (P = 0.02).

CONCLUSIONS

AF ablation improves invasive exercise hemodynamic parameters, exercise capacity, and quality of life in patients with concomitant AF and HFpEF.

Catheter Ablation vs Antiarrhythmic Drug Therapy for Treatment of Premature Ventricular Complexes: A Systematic Review

There is variability in treatment modalities for premature ventricular complexes (PVCs), including use of antiarrhythmic drug (AAD) therapy or catheter ablation (CA). This study reviewed evidence comparing CA vs AADs for the treatment of PVCs. A systematic review was performed from the Medline, Embase, and Cochrane Library databases, as well as the Australian and New Zealand Clinical Trials Registry, U.S. National Library of Medicine ClinicalTrials database, and the European Union Clinical Trials Register. Five studies (1 randomized controlled trial) enrolling 1,113 patients (57.9% female) were analyzed. Four of five studies recruited mainly patients with outflow tract PVCs. There was significant heterogeneity in AAD choice. Electroanatomic mapping was used in 3 of 5 studies. No studies documented intracardiac echocardiography or contact force-sensing catheter use. Acute procedural endpoints varied (2 of 5 targeted elimination of all PVCs). All studies had significant potential for bias. CA seemed superior to AADs for PVC recurrence, frequency, and burden. One study reported long-term symptoms (CA superior). Quality of life or cost-effectiveness was not reported. Complication and adverse event rates were 0% to 5.6% for CA and 9.5% to 21% for AADs. Future randomized controlled trials will assess CA vs AADs for patients with PVCs without structural heart disease (ECTOPIA [Elimination of Ventricular Premature Beats with Catheter Ablation versus Optimal Antiarrhythmic Drug Treatment]), with impaired LVEF (PAPS [Prospective Assessment of Premature Ventricular Contractions Suppression in Cardiomyopathy] Pilot), and with structural heart disease (CAT-PVC [Catheter Ablation Versus Amiodarone for Therapy of Premature Ventricular Contractions in Patients With Structural Heart Disease]). In conclusion, CA seems to reduce recurrence, burden, and frequency of PVCs compared with AADs. There is a lack of data on patient- and health care-specific outcomes such as symptoms, quality of life, and cost-effectiveness. Several upcoming trials will offer important insights for management of PVCs.

Impact of Catheter Ablation on Cognitive Function in Atrial Fibrillation: A Randomized Control Trial

BACKGROUND

Early postoperative cognitive dysfunction (POCD) has been reported following atrial fibrillation (AF) ablation. However, whether POCD is persistent long-term is unknown.

OBJECTIVES

The purpose of this study was to determine if AF catheter ablation is associated with persistent cognitive dysfunction at 12-month follow-up.

METHODS

This is a prospective study of 100 patients with symptomatic AF who failed at least 1 antiarrhythmic drug randomized to either ongoing medical therapy or AF catheter ablation and followed up for 12 months. Changes in cognitive performance were assessed using 6 cognitive tests administered at baseline and during follow-up (3, 6, and 12 months).

RESULTS

A total of 96 participants completed the study protocol. Mean age was 59 ± 12 years (32% women, 46% with persistent AF). The prevalence of new cognitive dysfunction in the ablation arm compared with the medical arm was as follows: at 3 months: 14% vs 2%; P = 0.03; at 6 months: 4% vs 2%; P = NS; and at 12 months: 0% vs 2%; P = NS. Ablation time was an independent predictor of POCD (P = 0.03). A significant improvement in cognitive scores was seen in 14% of the ablation arm patients at 12 months compared with no patients in the medical arm (P = 0.007).

CONCLUSIONS

POCD was observed following AF ablation. However, this was transient with complete recovery at 12-month follow-up.

Use of a novel smartphone-based application tool for enrolment and randomisation in pre-hospital clinical trials

The effective recruitment and randomisation of patients in pre-hospital clinical trials presents unique challenges. Owing to the time critical nature of many pre-hospital emergencies and limited resourcing, the use of traditional methods of randomisation that may include centralised telephone or web-based systems are often not practicable or feasible. Previous technological limitations have necessitated that pre-hospital trialists strike a compromise between implementing pragmatic, deliverable study designs, and robust enrolment and randomisation methodologies. In this commentary piece, we present a novel smartphone-based solution that has the potential to align pre-hospital clinical trial recruitment processes to that of best-in-practice in-hospital and ambulatory care setting studies. Running title: Smartphone application based randomisation in pre-hospital clinical trials.

Diagnostic evaluation of unexplained ventricular tachyarrhythmias in younger adults

BACKGROUND

The diagnostic work-up for cardiac arrest from ventricular tachyarrhythmias occurring in younger adults and structurally normal hearts is variable and often incomplete.

METHODS

We reviewed records for all recipients of a secondary prevention implantable cardiac defibrillator (ICD) younger than 60 years at a single quaternary referral hospital from 2010 to 2021. Patients with unexplained ventricular arrhythmias (UVA) were identified as those with no structural heart disease on echocardiogram, no obstructive coronary disease, and no clear diagnostic features on ECG. We specifically evaluated the adoption rate of five modalities of "second-line" cardiac investigations: cardiac magnetic resonance imaging (CMR), exercise ECG, flecainide challenge, electrophysiology study (EPS), and genetic testing. We also evaluated patterns of antiarrhythmic drug therapy and device-detected arrhythmias and compared them with secondary prevention ICD recipients with a clear etiology found on initial assessment.

RESULTS

One hundred and two recipients of a secondary prevention ICD under the age of 60 were analyzed. Thirty-nine patients (38.2%) were identified with UVA and were compared with the remaining 63 patients with VA of clear etiology (61.8%). UVA patients were younger (35.6 ± 13.0 vs. 46.0 ± 8.6 years, p < .001) and were more often female (48.7% vs. 28.6%, p = .04). CMR was performed in 32 patients with UVA (82.1%), whereas flecainide challenge, stress ECG, genetic testing, and EPS were only performed in a minority of patients. Overall, the use of a second-line investigation suggested an etiology in 17 patients with UVA (43.5%). Compared to patients with VA of clear etiology, UVA patients had lower rates of antiarrhythmic drug prescription (64.1% vs. 88.9%, p = .003) and had a higher rate of device-delivered tachy-therapies (30.8% vs. 14.3%, p = .045).

CONCLUSION

In this real-world analysis of patients with UVA, the diagnostic work-up is often incomplete. While CMR was increasingly utilized at our institution, investigations for channelopathies and genetic causes appear to be underutilized. Implementation of a systematic protocol for work-up of these patients requires further study.

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.

A Prospective, Multicentre Randomised Controlled Trial Comparing Catheter Ablation Versus Antiarrhythmic Drugs in Patients With Structural Heart Disease Related Ventricular Tachycardia: The CAAD-VT Trial Protocol

IMPORTANCE

Randomised trials have shown that catheter ablation (CA) is superior to medical therapy for ventricular tachycardia (VT) largely in patients with ischaemic heart disease. Whether this translates to patients with all forms and stages of structural heart disease (SHD-e.g., non-ischaemic heart disease) is unclear. This trial will help clarify whether catheter ablation offers superior outcomes compared to medical therapy for VT in all patients with SHD.

OBJECTIVE

To determine in patients with SHD and spontaneous or inducible VT, if catheter ablation is more efficacious than medical therapy in control of VT during follow-up.

DESIGN

Randomised controlled trial including 162 patients, with an allocation ratio of 1:1, stratified by left ventricular ejection fraction (LVEF) and geographical region of site, with a median follow-up of 18-months and a minimum follow-up of 1 year.

SETTING

Multicentre study performed in centres across Australia.

PARTICIPANTS

Structural heart disease patients with sustained VT or inducible VT (n=162).

INTERVENTION

Early treatment, within 30 days of randomisation, with catheter ablation (intervention) or initial treatment with antiarrhythmic drugs only (control).

MAIN OUTCOMES, MEASURES, AND RESULTS

Primary endpoint will be a composite of recurrent VT, VT storm (≥3 VT episodes in 24 hrs or incessant VT), or death. Secondary outcomes will include each of the individual primary endpoints, VT burden (number of VT episodes in the 6 months preceding intervention compared to the 6 months after intervention), cardiovascular hospitalisation, mortality (including all-cause mortality, cardiac death, and non-cardiac death) and LVEF (assessed by transthoracic echocardiography from baseline to 6-, 12-, 24- and 36-months post intervention).

CONCLUSIONS AND RELEVANCE

The Catheter Ablation versus Anti-arrhythmic Drugs for Ventricular Tachycardia (CAAD-VT) trial will help determine whether catheter ablation is superior to antiarrhythmic drug therapy alone, in patients with SHD-related VT.

TRIAL REGISTRY

Australian New Zealand Clinical Trials Registry (ANZCTR) TRIAL REGISTRATION ID: ACTRN12620000045910 TRIAL REGISTRATION URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=377617&isReview=true.

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.

The impact of coffee subtypes on incident cardiovascular disease, arrhythmias, and mortality: long-term outcomes from the UK Biobank

AIMS

Epidemiological studies report the beneficial effects of habitual coffee consumption on incident arrhythmia, cardiovascular disease (CVD), and mortality. However, the impact of different coffee preparations on cardiovascular outcomes and survival is largely unknown. The aim of this study was to evaluate associations between coffee subtypes on incident outcomes, utilizing the UK Biobank.

METHODS AND RESULTS

Coffee subtypes were defined as decaffeinated, ground, and instant, then divided into 0, <1, 1, 2-3, 4-5, and >5 cups/day, and compared with non-drinkers. Cardiovascular disease included coronary heart disease, cardiac failure, and ischaemic stroke. Cox regression modelling with hazard ratios (HRs) assessed associations with incident arrhythmia, CVD, and mortality. Outcomes were determined through ICD codes and death records. A total of 449 563 participants (median 58 years, 55.3% females) were followed over 12.5 ± 0.7 years. Ground and instant coffee consumption was associated with a significant reduction in arrhythmia at 1-5 cups/day but not for decaffeinated coffee. The lowest risk was 4-5 cups/day for ground coffee [HR 0.83, confidence interval (CI) 0.76-0.91, P < 0.0001] and 2-3 cups/day for instant coffee (HR 0.88, CI 0.85-0.92, P < 0.0001). All coffee subtypes were associated with a reduction in incident CVD (the lowest risk was 2-3 cups/day for decaffeinated, P = 0.0093; ground, P < 0.0001; and instant coffee, P < 0.0001) vs. non-drinkers. All-cause mortality was significantly reduced for all coffee subtypes, with the greatest risk reduction seen with 2-3 cups/day for decaffeinated (HR 0.86, CI 0.81-0.91, P < 0.0001); ground (HR 0.73, CI 0.69-0.78, P < 0.0001); and instant coffee (HR 0.89, CI 0.86-0.93, P < 0.0001).

CONCLUSION

Decaffeinated, ground, and instant coffee, particularly at 2-3 cups/day, were associated with significant reductions in incident CVD and mortality. Ground and instant but not decaffeinated coffee was associated with reduced arrhythmia.

Development and validation of the HARMS2-AF lifestyle risk score to predict incident AF

Background

Lifestyle risk factors (RFs) are a modifiable target in atrial fibrillation (AF) management. However, the relative contribution of individual lifestyle RFs to AF incidence has not been described.

Purpose

Development and validation of a novel AF-lifestyle risk score to determine AF risk in the general population.

Methods

The UK Biobank (UKB) is a large prospective cohort with outcomes measured &gt;10 years. In the UKB, we performed regression analysis of AF lifestyle RFs which were then evaluated in a multivariable model and a weighted score was developed. Next, the risk score was externally validated in the Framingham Heart Study (FHS) population. Kaplan-Meier estimates ascertained the 10-year risk of AF development.

Results

In the UKB, AF incidence was 5.3% among 302,926 participants, with a median time to AF 7.3 years (IQR 4.3–9.8). Hypertension, sleep apnoea, male sex, age, obesity (BMI&gt;30 kg/m2), alcohol and smoking were predictive variables (all p&lt;0.001); physical inactivity (OR 1.02,95% CI 0.97–1.10, p=0.3), diabetes (OR 0.98,95% CI 0.91–1.06, p=0.2) and BMI 27–30 kg/m2 (OR 1.02, 95% CI 0.97–1.07, p=0.424) were not significant. The HARMS2-AF score (Figure 1) had similar predictive performance (AUC=0.782, LogLoss 0.178, Brier Score 0.046) to the unweighted regression model (AUC 0.808) in the UKB. Validation in the FHS (AF incidence 6.7% of 7206 participants) maintained excellent predictive performance with an AUC of 0.747 (95% CI 0.724–0.769, Figure 2). A higher HARMS2-AF score (&gt;5 points) was associated with a heightened 10-year AF risk (score 5–9: OR 9.35, score 10–14: OR 33.34).

Conclusions

The HARMS2-AF score is a novel lifestyle risk score which may help identify individuals at risk of AF and assists in general population screening.

Funding Acknowledgement

Type of funding sources: None.

Catheter ablation in atrial fibrillation and heart failure with preserved ejection fraction improves peak pulmonary capillary wedge pressure, exercise capacity and quality of life: RCT STALL HFpEF

Introduction

Atrial fibrillation (AF) frequently accompanies heart failure with preserved ejection fraction (HFpEF). AF exacerbates HFpEF through adverse haemodynamic effects. In turn, HFpEF promotes AF through adverse left atrial remodelling. Observational data suggest sinus rhythm restoration improves outcomes in patients with AF and HFpEF. However, there are no randomised data examining the effects of rhythm control with catheter-based AF ablation on HFpEF outcomes.

Purpose

To compare the effects of AF ablation versus usual medical therapy on markers of HFpEF severity, including exercise haemodynamics, natriuretic peptide levels and patient symptoms.

Methods

Patients with symptomatic AF and HFpEF underwent exercise right heart catheterization (RHC) and cardiopulmonary exercise testing (CPET). HFpEF diagnosis was based on left ventricular ejection fraction (LVEF) ≥50%, elevated natriuretic peptide and echocardiographic diastolic impairment. HFpEF was confirmed on exercise RHC based on peak exercise pulmonary capillary wedge pressure (PCWP) of ≥25mmHg. Patients were randomised to AF ablation versus medical therapy, with investigations repeated at 6 months. The primary outcome was change in PCWP on follow-up.

Results

31 patients aged 66.1±7.5 years were randomized to AF ablation (16) versus medical therapy (15), with 51.6% female and 80.6% persistent AF. Baseline characteristics were comparable across groups. Paired analyses of ablation cohort showed significant reductions in peak PCWP (29.6±3.7 vs 25.9±4.6 mmHg, p&lt;0.01), PCWP indexed for workload (39.0±57.9 vs 33.0±50.5 mmHg/W/kg, p&lt;0.01), and BNP (146.2±80.5 vs 82.2±75.4 pg/mL, p=0.01); and increased resting cardiac output (4.6±0.9 vs 5.6±1.2 L/min, p=0.01), peak cardiac output (9.6±4.2 vs 10.4±3.7 L/min, p=0.02), peak (30s averaged) VO2 (1875.1±759.2 vs 2193.7±878.1 mL/min, p&lt;0.01), peak absolute VO2 (1937.3±739.3 vs 2216.3±861.9 mL/min, p&lt;0.01), peak (30s averaged) relative VO2 (19.4±5.9 vs 22.9±7.4 ml/kg/min) and peak workload (162.0±81.1 vs 184.4±83.4 W, p&lt;0.01). Quality of life scores improved: AFEQT (45.3±20.9 vs 75±20.7, p&lt;0.01) and MLHF (53±23.3 vs 17.5±22.8, p&lt;0.01). Reversal of HFpEF by PCWP criteria occurred in 31.2% following AF ablation, and 50% among those free from arrhythmia recurrence. In the medical arm, there were no significant differences in RHC, CPET, and natriuretic peptide outcomes on follow-up versus baseline. Repeated measures mixed ANOVA testing showed significant time-randomisation interaction on peak VO2, absolute peak VO2, peak relative VO2, AFEQT/ MLHF scores, suggesting that significant improvements in these parameters were related to AF ablation.

Conclusion

In patients with concomitant AF and HFpEF, AF ablation improves invasive exercise haemodynamic parameters, increases exercise capacity, and enhances quality of life. Successful AF ablation may reverse the clinical syndrome of HFpEF in a subset of cases.

Funding Acknowledgement

Type of funding sources: None.

Clinical risk prediction for left atrial appendage thrombus among patients with atrial fibrillation

Background

Exclusion of left atrial appendage thrombus (LAAT) by transoesophageal echocardiography (TOE) is recommended in patients with inadequate anticoagulation prior to direct cardioversion (DCR) or catheter ablation for atrial fibrillation/flutter (AF/AFL). LAAT risk factors in this population remain poorly defined.

Purpose

Determine LAAT predictors in AF/AFL patients undergoing pre-procedural TOE.

Methods

We evaluated available clinical and transthoracic echocardiographic (TTE) parameters in AF/AFL patients undergoing TOE between 1999–2022 in our institution in Melbourne, Australia. Regression analysis identified predictors of LAAT, which were applied to a weighted score developed in the derivation cohort (70%) and validated in the remaining 30%.

Results

Of 627 patients (age 62±12 years, 27% female, AF 84%,AFL 16%, left ventricular ejection fraction (LVEF) 44±20%), 24% had LAAT and 13.8% dense spontaneous echo contrast precluding DCR. Anticoagulation was NOAC 56.5%, warfarin 32.1% and none in 11.4%. In the LAAT cohort, thrombus resolution occurred in 39% on serial transoesophageal imaging with a median time to resolution of 131 days (IQR 54–398).

Diabetes (p=0.004), prior stroke (p=0.009), coronary disease (p=0.015), renal impairment (p&lt;0.001) and CHADS2VASc &gt;2 (73% vs. 55%, p&lt;0.001) were higher in the LAAT cohort. Age (p=0.093), gender (p=0.689), BMI (p=0.828), anticoagulant type (p=0.316) and diabetes (p=0.107) were not univariate predictors, whereas anticoagulation duration (&lt;30 days), creatinine and TTE markers of remodeling (LVEF, LAVI, RVSP and TAPSE) were independent predictors on univariate and multivariate regression; CHADS2VASc was not significant after adjustment (p=0.090). The weighted risk model included continuous (age, creatinine, LVEF, LAVI, TAPSE and RVSP) and categorical (anticoagulation duration) variables with excellent predictive performance: AUC 0.872 (95% CI 0.798–0.946), PPV 91%, NPV 70% and accuracy 80%.

Conclusion

A novel LAAT risk model comprising clinical and echocardiographic parameters enhances risk prediction over CHADS2VASc in AF/AFL and may guide the need for pre-procedural TOE imaging.

Funding Acknowledgement

Type of funding sources: None.

Impact of CPAP on the Atrial Fibrillation Substrate in Obstructive Sleep Apnea: The SLEEP-AF Study

BACKGROUND

Observational studies report that obstructive sleep apnea (OSA) is associated with an increasingly remodeled atrial substrate in atrial fibrillation (AF). However, the impact of OSA management on the electrophysiologic substrate has not been evaluated.

OBJECTIVES

In this study, the authors sought to determine the impact of OSA management on the atrial substrate in AF.

METHODS

We recruited 24 consecutive patients referred for AF management with at least moderate OSA (apnea-hypopnea index [AHI] ≥15). Participants were randomized in a 1:1 ratio to commence continuous positive airway pressure (CPAP) or no therapy (n = 12 CPAP; n = 12 no CPAP). All participants underwent invasive electrophysiologic study (high-density right atrial mapping) at baseline and after a minimum of 6 months. Outcome variables were atrial voltage (mV), conduction velocity (m/s), atrial surface area <0.5 mV (%), proportion of complex points (%), and atrial effective refractory periods (ms). Change between groups over time was compared.

RESULTS

Clinical characteristics and electrophysiologic parameters were similar between groups at baseline. Compliance with CPAP therapy was high (device usage: 79% ± 19%; mean usage/day: 268 ± 91 min) and resulted in significant AHI reduction (mean reduction: 31 ± 23 events/h). There were no differences in blood pressure or body mass index between groups over time. At follow-up, the CPAP group had faster conduction velocity (0.86 ± 0.16 m/s vs 0.69 ± 0.12 m/s; P (time × group) = 0.034), significantly higher voltages (2.30 ± 0.57 mV vs 1.94 ± 0.72 mV; P < 0.05), and lower proportion of complex points (8.87% ± 3.61% vs 11.93% ± 4.94%; P = 0.011) compared with the control group. CPAP therapy also resulted in a trend toward lower proportion of atrial surface area <0.5 mV (1.04% ± 1.41% vs 4.80% ± 5.12%; P = 0.065).

CONCLUSIONS

CPAP therapy results in reversal of atrial remodeling in AF and provides mechanistic evidence advocating for management of OSA in AF.

Long-Term Implications of Pacemaker Insertion in Younger Adults: A Single Centre Experience

BACKGROUND

The long-term implications of pacemaker insertion in younger adults are poorly described in the literature.

METHODS

We performed a retrospective analysis of consecutive younger adult patients (18-50 yrs) undergoing pacemaker implantation at a quaternary hospital between 1986-2020. Defibrillators and cardiac resynchronisation therapy devices were excluded. All clinical records, pacemaker checks and echocardiograms were reviewed.

RESULTS

Eighty-one (81) patients (median age 41.0 yrs IQR=35-47.0, 53% male) underwent pacemaker implantation. Indications were complete heart block (41%), sinus node dysfunction (33%), high grade AV block (11%) and tachycardia-bradycardia syndrome (7%). During a median 7.9 (IQR=1.1-14.9) years follow-up, nine patients (11%) developed 13 late device-related complications (generator or lead malfunction requiring reoperation [n=11], device infection [n=1] and pocket revision [n=1]). Five (5) of these patients were <40 years old at time of pacemaker insertion. At long-term follow-up, a further nine patients (11%) experienced pacemaker-related morbidity from inadequate lead performance managed with device reprogramming. Sustained ventricular tachycardia was detected in two patients (2%). Deterioration in ventricular function (LVEF decline >10%) was observed in 14 patients (17%) and seven of these patients required subsequent biventricular upgrade. Furthermore, four patients (5%) developed new tricuspid regurgitation (>moderate-severe). Of 69 patients with available long-term pacing data, minimal pacemaker utilisation (pacing <5% at all checks) was observed in 13 (19%) patients.

CONCLUSIONS

Pacemaker insertion in younger adults has significant long-term implications. Clinicians should carefully consider pacemaker insertion in this cohort given risk of device-related complications, potential for device under-utilisation and issues related to lead longevity. In addition, patients require close follow-up for development of structural abnormalities and arrhythmias.

Prediction of Pacemaker Requirement in Patients With Unexplained Syncope: The DROP Score

BACKGROUND

Implantable loop recorders (ILR) are increasingly utilised in the evaluation of unexplained syncope. However, they are expensive and do not protect against future syncope.

OBJECTIVES

To compare patients requiring permanent pacemaker (PPM) implantation during ILR follow-up with those without abnormalities detected on ILR in order to identify potential predictors of benefit from upfront pacing.

METHODS

We analysed 100 consecutive patients receiving ILR: Group 1 (n=50) underwent PPM insertion due to bradyarrhythmias detected on ILR; Group 2 (n=50) had no arrhythmias detected on ILR over >3 years follow-up. Baseline clinical characteristics, syncope history, electrocardiographic and echocardiographic parameters were assessed to identify predictors of ultimate requirement for pacing.

RESULTS

Group 1 (64% male, median age 70.8 years; IQR 65.5-78.8) were older than Group 2 (58% male, median 60.2 years; IQR 44.0-73.0 p=0.001) and were less likely to have related historical factors such as overheating, posture and exercise (98% vs 70% p<0.001). PR interval was also longer in Group 1 (192±51 vs 169±23 p=0.006) with greater prevalence of distal conduction system disease (30% vs 4.3% p=0.002). Significant univariate predictors for PPM insertion were distal conduction disease (p=0.007), first degree atrioventricular (AV) block (p=0.003), absence of precipitating factors (p=0.004), and age >65 years (p=0.001). Injury sustained, recurrent syncope, history of atrial fibrillation (AF) or heart failure, left atrial (LA) size and left ventricular ejection fraction (LVEF) were not predictive. These significant predictors were incorporated into the DROP score¹ (0-4). Using time-to-event analysis, no patients with a score of 0 progressed to pacing, while higher scores (3-4) strongly predicted pacing requirement (log-rank p<0.001).

CONCLUSION

The DROP score may be helpful in identifying patients likely to benefit from upfront permanent pacemaker (PPM) insertion following unexplained syncope. Larger prospective studies are required to validate this tool.

Arrhythmias and Their Electrophysiological Mechanisms in Takotsubo Syndrome: A Narrative Review

BACKGROUND

Takotsubo syndrome (TTS), an acute and usually reversible condition, is associated with both tachy- and bradyarrhythmias. Such arrhythmias can be life-threatening, e.g. ventricular tachycardia and fibrillation, and associated with cardiac arrest. Others, such as atrioventricular block, persist and require long-term device therapy. In this narrative review, we aim to provide a summary of the current literature on arrhythmias in TTS and their clinical sequelae.

METHODS

PubMed and Medline databases were searched with various permutations of TTS, arrhythmias and beta-adrenoceptors. After application of exclusion criteria and review, 84 articles were included.

RESULTS

Although there are no specific electrocardiograph (ECG) findings in TTS to differentiate it from ST-elevation myocardial infarction, suggestive patterns include small QRS amplitude, ST segment elevation without reciprocal ST depression and prolonged QT interval. Atrial tachyarrhythmias (incidence of 5-15%) are associated with a more unwell patient cohort. Ventricular arrhythmias (incidence 4-14%) are often associated with prolonged QT interval and are a cause of sudden death in TTS. Bradyarrhythmias are less common (incidence 1.3-2.5%), but have been reported with TTS, and usually persist beyond the acute phase.

CONCLUSIONS

Takotsubo syndrome, though considered primarily a disease of the myocardium, carries multiple arrhythmic manifestations that affect short- and long-term prognosis. The management of such arrhythmias represents a constantly evolving area of research.