Trends in adoption of extravascular cardiac implantable electronic devices: the Dutch cohort.

INTRODUCTION: Conventional implantable cardioverter-defibrillators (ICDs) and pacemakers carry a risk of pocket- and lead-related complications in particular. To avoid these complications, extravascular devices (EVDs) have been developed, such as the subcutaneous ICD (S-ICD) and leadless pacemaker (LP). However, data on patient or centre characteristics related to the actual adoption of EVDs are lacking. OBJECTIVE: To assess real-world nationwide trends in EVD adoption in the Netherlands. METHODS: Using the Netherlands Heart Registration, all consecutive patients with a de novo S­ICD or conventional single-chamber ICD implantation between 2012-2020, or de novo LP or conventional single-chamber pacemaker implantation between 2014-2020 were included. Trends in adoption are described for various patient and centre characteristics. RESULT: From 2012-2020, 2190 S­ICDs and 10,683 conventional ICDs were implanted; from 2014-2020, 712 LPs and 11,103 conventional pacemakers were implanted. The general use has increased (S-ICDs 8 to 21%; LPs 1 to 8%), but this increase seems to have reached a plateau. S­ICD recipients were younger than conventional ICD recipients (p < 0.001) and more often female (p < 0.001); LP recipients were younger than conventional pacemaker recipients (p < 0.001) and more often male (p = 0.03). Both S­ICDs and LPs were mainly implanted in high-volume centres with cardiothoracic surgery on-site, although over time S­ICDs were increasingly implanted in centres without cardiothoracic surgery (p < 0.001). CONCLUSION: This nationwide study demonstrated a relatively quick adoption of innovative EVDs with a plateau after approximately 4 years. S­ICD use is especially high in younger patients. EVDs are mainly implanted in high-volume centres with cardiothoracic surgery back-up, but S­ICD use is expanding beyond those centres.

Long-term success of a multi-electrode substrate mapping and ablation strategy versus a classic single tip mapping and ablation strategy for ventricular tachycardia ablation in patients with ischemic cardiomyopathy.

INTRODUCTION: Over the past years, mapping and ablation techniques for the treatment of ventricular tachycardia (VT) have evolved rapidly. High Density (HD) substrate mapping is now routine and pre-procedural imaging is increasingly used. The additional value of these techniques for long-term VT-free survival is not clear. METHODS: We compared baseline and procedural characteristics, procedural success, safety and outcome of mapping and ablation of ventricular tachycardia in patients with ischemic heart disease between two groups. (1) Low Density (LD) group: VT mapping and ablation with a 4 mm single tip catheter (2) HD group: HD substrate mapping with the Pentaray (Biosense Webster, USA) or HD Grid (Abbott, USA) catheter and ablation with a 4 mm single tip catheter. RESULTS: VT ablation was performed in 133 patients (71 patients in LD group and 62 patients in HD group). The median follow-up was 5.0 years in LD group and 2.0 years in HD group. One-, two-, and five-year VT recurrence rates were 47%, 56%, and 65% in the LD group versus 39%, 50%, and 55% in the HD group (log-rank test for VT recurrence p = .70). One-, two-, and five-year ICD shock recurrence rates were 14%, 18%, and 24% in the LD group versus 8%, 15%, and 19% in the HD group (log-rank test for ICD-shock p = .79). All-cause mortality, cardiac (non-arrhythmic), and arrhythmic death, were similar in both groups. Severe procedural complications (tamponade, stroke, or procedural death) occurred in four patients (5%, 1 vascular, 3 tamponade) in the LD group versus two patients (3%, both tamponade) in the HD group (NS). In univariate and multivariable analysis, only a higher LVEF was significantly associated with VT-free survival. HD mapping was not significantly associated with VT-free survival. Anterior infarct location and age were significantly associated with ICD recurrent shock in both univariate and multivariable analyses. CONCLUSIONS: In patients with ischemic cardiomyopathy, a HD substrate mapping, and ablation strategy did not lead to higher VT-free survival and shock-free survival compared to a single tip mapping and ablation strategy. In this study, only LVF is an independent predictor for VT recurrence. Anterior infarct location and age predict recurrent ICD shocks.

High-density mapping for ablation of atypical atrial flutters - procedural characteristics related to outcome.

BACKGROUND: High-density (HD) mapping is increasingly used to characterize arrhythmic substrate for ablation of atypical atrial flutters (AAFl). However, results on clinical outcomes and factors that are associated with arrhythmia recurrence are scarce. METHODS: Single-center, prospective, observational cohort study that enrolled patients with catheter ablation for AAFl using a HD mapping system and a grid-shaped mapping catheter. Procedural characteristics, rates of atrial flutter recurrence, and factors that were associated with atrial flutter recurrence were evaluated. RESULTS: Sixty-one patients with a total of 94 AAFl were included in the cohort. HD mapping was used to successfully identify the flutter circuit of 80/94 AAFl. The circuit was not identified for 14/94 AAFl in 11 patients. Critical isthmuses were identified and ablated in 29 patients (48%). Acute procedural success was achieved in 52 patients (85%), and 37 patients (61%) remained free from atrial flutter recurrence during a follow up of 1.3 [1.0-2.1] years. Atrial flutter recurrence was univariably associated with presence of a non-identified flutter circuit (HR:2.6 95% CI [1.1-6.3], p = .04) and critical isthmus-targeted ablation (HR:0.4 [0.15-0.90], p = .03). In multivariable regression analyses, critical isthmus ablation remained significant (HR:0.4 [0.16-0.97], p = .04), whereas presence of a non-identified flutter did not (HR:2.4 [0.96-5.8], p = .06). CONCLUSION: HD mapping was successfully used to identify the majority of AAFl circuits. Ablation resulted in freedom from atrial flutter recurrence in 61% of the cohort. Successful identification of all flutter circuits and critical isthmuses appears to be beneficial for long-term outcomes.

NL-EVDR: Netherlands-ExtraVascular Device Registry.

Cardiac implantable electronic device (CIED) therapy is an essential element in treating cardiac arrhythmias. Despite their benefits, conventional transvenous CIEDs are associated with a significant risk of mainly pocket- and lead-related complications. To overcome these complications, extravascular devices (EVDs), such as the subcutaneous implantable cardioverter-defibrillator and intracardiac leadless pacemaker, have been developed. In the near future, several other innovative EVDs will become available. However, it is difficult to evaluate EVDs in large studies because of high costs, lack of long-term follow-up, imprecise data or selected patient populations. To improve evaluation of these technologies, real-world, large-scale, long-term data are of utmost importance. A Dutch registry-based study seems to be a unique possibility for this goal due to early involvement of Dutch hospitals in novel CIEDs and an existing quality control infrastructure, the Netherlands Heart Registration (NHR). Therefore, we will soon start the Netherlands-ExtraVascular Device Registry (NL-EVDR), a Dutch nationwide registry with long-term follow-up of EVDs. The NL-EVDR will be incorporated in NHR's device registry. Additional EVD-specific variables will be collected both retrospectively and prospectively. Hence, combining Dutch EVD data will provide highly relevant information on safety and efficacy. As a first step, a pilot project has started in selected centres in October 2022 to optimise data collection.

Early or Delayed Cardioversion in Recent-Onset Atrial Fibrillation.

BACKGROUND: Patients with recent-onset atrial fibrillation commonly undergo immediate restoration of sinus rhythm by pharmacologic or electrical cardioversion. However, whether immediate restoration of sinus rhythm is necessary is not known, since atrial fibrillation often terminates spontaneously. METHODS: In a multicenter, randomized, open-label, noninferiority trial, we randomly assigned patients with hemodynamically stable, recent-onset (<36 hours), symptomatic atrial fibrillation in the emergency department to be treated with a wait-and-see approach (delayed-cardioversion group) or early cardioversion. The wait-and-see approach involved initial treatment with rate-control medication only and delayed cardioversion if the atrial fibrillation did not resolve within 48 hours. The primary end point was the presence of sinus rhythm at 4 weeks. Noninferiority would be shown if the lower limit of the 95% confidence interval for the between-group difference in the primary end point in percentage points was more than -10. RESULTS: The presence of sinus rhythm at 4 weeks occurred in 193 of 212 patients (91%) in the delayed-cardioversion group and in 202 of 215 (94%) in the early-cardioversion group (between-group difference, -2.9 percentage points; 95% confidence interval [CI], -8.2 to 2.2; P = 0.005 for noninferiority). In the delayed-cardioversion group, conversion to sinus rhythm within 48 hours occurred spontaneously in 150 of 218 patients (69%) and after delayed cardioversion in 61 patients (28%). In the early-cardioversion group, conversion to sinus rhythm occurred spontaneously before the initiation of cardioversion in 36 of 219 patients (16%) and after cardioversion in 171 patients (78%). Among the patients who completed remote monitoring during 4 weeks of follow-up, a recurrence of atrial fibrillation occurred in 49 of 164 patients (30%) in the delayed-cardioversion group and in 50 of 171 (29%) in the early-cardioversion group. Within 4 weeks after randomization, cardiovascular complications occurred in 10 patients and 8 patients, respectively. CONCLUSIONS: In patients presenting to the emergency department with recent-onset, symptomatic atrial fibrillation, a wait-and-see approach was noninferior to early cardioversion in achieving a return to sinus rhythm at 4 weeks. (Funded by the Netherlands Organization for Health Research and Development and others; RACE 7 ACWAS ClinicalTrials.gov number, NCT02248753.).

Dielectric imaging for electrophysiology procedures: The technology, current state, and future potential.

Electroanatomic mapping systems have become an essential tool to guide the identification and ablation of arrhythmic substrate. Recently, a novel guiding system for electrophysiology procedures was introduced that uses dielectric sensing to perform high resolution anatomical imaging. Dielectric imaging systems use electrical fields to differentiate anatomic structures based on their conductivity and permittivity. This technique enables non-fluoroscopic, noncontact mapping of anatomic structures, assessment of pulmonary vein occlusion state during cryoballoon ablation, and has the potential to assess for additional tissue characterization including tissue thickness and tissue type. This article elaborates on the functioning and potential of dielectric imaging systems and provides two cases to illustrate the clinical impact for electrophysiology procedures.

Efficacy and safety of the GOLD FORCE multicentre randomized clinical trial: multielectrode phased radiofrequency vs. irrigated radiofrequency single-tip catheter with contact force ablation for treatment of symptomatic paroxysmal atrial fibrillation.

AIMS: Pulmonary vein isolation (PVI) for atrial fibrillation (AF) has become increasingly safe and effective with the evolution of single-tip ablation catheters aided by contact force sensing (ST-CF) and single-shot devices such as the second-generation pulmonary vein ablation catheter (PVAC) Gold multi-electrode array. The multicentre randomized GOLD FORCE trial was conducted to evaluate non-inferiority of safety and efficacy of PVAC Gold PVI compared to ST-CF ablation for paroxysmal AF. METHODS AND RESULTS: The primary efficacy endpoint documented AF recurrence ≥30 s was assessed by time-to-first-event analysis after a 90-day blanking period using repeated 7-day Holters. Secondary endpoints include acute success and procedural characteristics. Safety endpoints included procedural complications, stroke/transient ischaemic attack (TIA), tamponade, bleeding, and access site complications. Two hundred and eight patients underwent randomization and PVI (103 assigned to PVAC Gold, 105 to ST-CF). Acute success rates were 95% and 97% for PVAC Gold and ST-CF, respectively. At 12 months, AF recurrence was observed in 46.6% of the PVAC Gold group and in 26.2% of the ST-CF group [absolute efficacy difference 20.4% (95% confidence interval, CI 7.5-33.2%), hazard ratio 2.05 (95% CI 1.28-3.29), P = 0.003]. PVAC Gold had significantly shorter procedure and ablation times. Complication rates were 5.7% and 4.9% for PVAC Gold and ST-CF, respectively (P = 0.782). CONCLUSION: In this multicentre randomized clinical trial, ablation with ST-CF and PVAC Gold ablation catheters non-inferiority for efficacy was not met. AF recurrence was significantly more frequent in the PVAC Gold group compared to single-tip contact force group. Both groups had similarly low rates of adverse events. PVAC Gold ablation had significantly shorter procedure and ablation times.

Non-transvenous ICD therapy: current status and beyond.

Subcutaneous implantable cardioverter/defibrillators (S-ICDs) have been developed to offer ICD treatment to patients without venous access to the heart and to overcome complications associated with transvenous leads, particularly lead fracture/insulation defects and endocarditis. Several studies and registries have demonstrated the feasibility and safety of S­ICD in different groups of patients. Further developments in S­ICD technology involve the combination with devices that can provide anti-bradycardia and anti-tachycardia pacing if needed. The extravascular ICD (EV-ICD) is a new system that similarly offers ICD therapy without a transvenous lead but uses a substernal instead of a subcutaneous lead to facilitate detection of ventricular fibrillation and to provide anti-tachycardia and also temporary anti-bradycardia pacing. The first animal but also clinical data on EV-ICDs have been published. This review discusses the current state, potential advantages and limitations, and future research of both S­ICD and EV-ICD.

ICD implantation for secondary prevention in patients with ventricular arrhythmia in the setting of acute cardiac ischemia and a history of myocardial infarction.

INTRODUCTION: In patients with a prior myocardial infarction (MI) but preserved left ventricular (LV) function, sustained ventricular arrhythmias (VAs) may arise in the setting of an acute coronary syndrome (ACS). It is unknown whether an implantable cardioverter-defibrillator (ICD) is mandatory in these patients as VA might be triggered by a reversible cause. The purpose of this study is to analyze the benefit of ICD therapy in this patient population. METHODS: We conducted a retrospective observational study in ICD recipients implanted from 2008 to 2011. The study group consisted of patients with sustained VA in the setting of an ACS, with a history of MI, but with left ventricular ejection fraction (LVEF) greater than 35 (group A). The two control groups consisted of patients admitted with VA with a history of MI, but without ACS at presentation, either with LVEF greater than 35% (group B) or ≤35% (group C). The primary endpoint was the number of patients with appropriate ICD therapy (antitachycardia pacing or shock). RESULTS: A total of 291 patients were included with a mean follow-up of 5.3 years. Appropriate ICD therapy occurred in 45.6% of the patients in group A vs 51.6% and 60.4% in groups B and C (P = .11). In group A, 31.1% received an appropriate ICD shock vs 34.7% and 44.3% in control groups B and C (P = .12). CONCLUSION: On the basis of these data, ICD implantation seems warranted in patients with history of MI presenting with VA in the setting of an ACS, despite preserved LV function and adequate revascularization. Further trials, preferably randomizes, should be performed to address these findings.

Left atrial catheter ablation in patients with previously implanted left atrial appendage closure devices.

AIMS: Left atrial appendage closure (LAAC) is increasingly used as an alternative to oral anticoagulation (OAC) for stroke prevention in atrial fibrillation (AF) patients. Feasibility and safety of left atrial (LA) catheter ablation (CA) in patients with previously implanted LAAC devices have not been well studied. We report on the feasibility, safety, and efficacy of LA CA in the presence of a previously implanted LAAC device. METHODS AND RESULTS: In this prospective cohort study consecutive patients that underwent LA CA with a previously implanted Watchman device were included. Periprocedural characteristics and long-term clinical follow-up were evaluated. Twenty-three LA CA procedures were performed in 19/162 AF patients with previously implanted Watchman devices [47% male, age 63.9 ± 6.2 years, CHA2DS2-VASc 4.0 (3.0-5.0); HASBLED 3.0 (2.0-4.0); 63% paroxysmal]. Left atrial CA was performed with irrigated radiofrequency (RF; n = 20, 87%) or phased RF (n = 3, 13%) in a mean of 18 months after LAAC implantation (range 4-80 months). Targets of CA consisted of pulmonary vein isolation (n = 19, 83%), superior vena cava isolation (n = 13, 57%), and additional linear lesions (n = 8, 35%). Procedures were carried out under vitamin K antagonist (VKA; n = 6, 26%), non-VKA OAC (NOAC; n = 8, 35%), or single antiplatelet therapy alone (n = 9, 39%). Left atrial CA was successful without any signs of interference from the device. Procedure-related complications were not observed. During a mean follow-up of 28 months, 11 patients (58%) had AF recurrence. CONCLUSION: Left atrial CA after LAAC appears to be feasible, effective, and safe in this single centre cohort. Previously implanted Watchman device should not be a reason to relinquish CA in symptomatic AF patients, even in patients on single antiplatelet therapy alone.

Six-year follow-up of the initial Dutch subcutaneous implantable cardioverter-defibrillator cohort: Long-term complications, replacements, and battery longevity.

INTRODUCTION: Experience with the subcutaneous implantable cardioverter-defibrillator (S-ICD) is expanding rapidly. However, data on long-term performance or complications related to elective generator replacement are lacking. METHODS: Follow-up (FU) data of all patients implanted between December 2008 and April 2011 were collected. Complications were defined as those requiring surgical intervention. Kaplan-Meier estimates for complication and shock rates, with corresponding 95% confidence intervals (CI), were calculated. RESULTS: One hundred and eighteen patients were included. Median FU was 6.1 years (IQR 5.6-6.5 years). Short-term complication rate (0-30 days) was 3% (CI 0-6%). Long-term complication rate at 6 years was 19% (CI 12-26%), corresponding with an annual complication rate of 3%. One patient in this cohort developed a need for a transvenous ICD (TV-ICD) in order to provide pacing for bradycardia (1%). Six patients were implanted with a TV-ICD after experiencing an S-ICD complication for which extraction was necessary. In total, 10 S-ICDs were extracted; none resulted in a complication. Eight patients had a nonsystemic ICD-related infection and no lead failures were observed. The majority, 68 (58%) patients, received an elective generator replacement. Two patients had a complication related to generator replacement (3%). Battery longevity was 5.6 years (IQR 5.2-6.1). Appropriate and inappropriate shock rates of 6-year estimates were 17% (CI 9-25%) and 21% (CI 15-27%), respectively. CONCLUSIONS: This cohort represents the longest follow-up to date and shows a low annual complication rate without lead failures or systemic infections. Battery longevity of the first S-ICD generation results in relative early generator replacement procedures.

A combined epicardial implantation and subsequent extraction strategy in pacemaker device infection in pacemaker-dependent patients.

INTRODUCTION: Treatment infections is challenging in pacemaker (PM) dependent patients. We proposed a novel implantation strategy for this group of patients. METHODS: Patients who were PM dependent and were admitted with a PM infection received a combined procedure of left ventricular (LV) epicardial implantation of a PM lead and subsequent extraction of the infected system. No temporary pacing wire was used and the PM generator was placed in the left flank. RESULTS: Between 2012 and 2015 we treated 16 patients who were PM dependent and with a PM infection. The majority of patients were male (81% [13/16]) and the median age was 71 years (50-91). The cause of infection was valvular endocarditis in 38% (6/16), lead infection in 25% (4/16), and isolated pocket infection in 38% (6/16). All patients underwent epicardial implantation of a LV lead (1084T bipolar lead; St. Jude Medical Myodex, St. Paul, MN, USA) and extraction of the infected device. There was no occurrence of periprocedural mortality and no postprocedural tamponades. There was one complication in the form of a hemorrhage at the infected device extraction site. In the median follow-up period of 17 months there were four of 16 deaths, none of which were attributable to epicardial LV implantation. LV-lead threshold was 1.1V (±0.7V) upon implantation that increased to 1.2V (±0.6V) at 0.4-ms pulse duration. There were no reinfections of the epicardial lead or device. CONCLUSION: Epicardial left ventricle PM implantation and subsequent extraction of an infected PM in PM-dependent patients is feasible and safe with good long-term outcome.

Effects of epicardial versus transvenous left ventricular lead placement on left ventricular function and cardiac perfusion in cardiac resynchronization therapy: A randomized clinical trial.

INTRODUCTION: Optimal left ventricular (LV) lead position in patients undergoing cardiac resynchronization therapy (CRT) is crucial to achieve an optimal effect on hemodynamics. Due to various difficulties, up to 30% of transvenous LV lead placements fail, or a suboptimal position is achieved. Surgical epicardial LV lead placement could be performed at a position anticipated to be the optimal site. This could have a more favorable effect, which may be expressed by increased improvement in left ventricular ejection fraction (LVEF) and cardiac perfusion. The objective of this trial is to compare transvenous versus epicardial LV lead placement in CRT in a randomized fashion METHODS AND RESULTS: Fifty-two patients were randomized to either epicardial or transvenous approach. All patients received an ICD with CRT. Patients were followed for 6 months after device implant. Primary endpoint was the degree of change in cardiac perfusion measured by myocardial perfusion scintigraphy. LVEF equally improved in both groups, from 24% to 36% in the transvenous group versus 25% to 35% in the epicardial group (P = 0.797). Cardiac perfusion, expressed as summed stress score, improved in both groups without a significant difference as well (P = 0.727). Complication rate was similar, respectively 6 and 7 patients had any complication. Admission time was significantly longer in the epicardial group with 2 (2-7) versus 3 (2-32) days (P <0.001). CONCLUSION: Epicardial LV lead placement does not result in additional improvement of LVF or myocardial perfusion compared to the conventional transvenous in CRT.

Preliminary findings on the safety of 1.5 and 3 Tesla magnetic resonance imaging in cardiac pacemaker patients.

INTRODUCTION: Modern pacemakers are designed to allow patients to undergo magnetic resonance imaging (MRI) under a set of specific conditions. Aim of this study is to provide confirmatory evidence of safety and performance of a new pacing system (ImageReady™, Boston Scientific) in patients undergoing 1.5 and 3T MRI. METHODS AND RESULTS: Two prospective, nonrandomized, single-arm studies were designed to provide confirmatory data of no impact of MRI on device function, lead parameters, and patient conditions in subjects implanted with the system undergoing a clinically non-indicated 1.5T and 3T MRI, respectively. Device measurements were done within 1 hour before and after the scan and at 1 month follow-up. Thirty-two subjects underwent MRI visit (17 subjects with 1.5T MRI and 15 subjects with 3T MRI). There were no unanticipated adverse effects related to the pacemaker. Device measurements taken pre- and post-MRI scan did not show any clinical relevant change that could indicate an effect of the MRI on the device or at the lead-tissue interface (RV threshold change: 0.01 ± 0.13 V, P = 0.60; RA threshold change: 0.01 ± 0.11 V, P = 0.53; R wave change: -0.44 ± 1.73 mV, P = 0.36; R wave change: 0.12 ± 1.67 mV, P = 0.73), with data confirmed at 1-month follow-up visit. CONCLUSION: The study documented safety of the pacing system in the 1.5T and 3T MRI environment by showing no adverse events related to device or MRI scan. Additional data are required to cover the more complex scenarios involving different diagnostic needs, conditions of use, clinical conditions, and new emerging technologies.

Inappropriate Shock Due to T-Wave Oversensing by a Subcutaneous ICD after Alcohol Septal Ablation for Hypertrophic Cardiomyopathy.

A 53-year-old female patient with hypertrophic obstructive cardiomyopathy (HOCM) was admitted for alcohol septal ablation (ASA). A subcutaneous internal cardioverter defibrillator (S-ICD) was implanted for primary prevention. After ASA, the patient developed a right bundle branch block, and the S-ICD delivered a total of five inappropriate shocks due to T-wave oversensing (TWOS). TWOS is a relatively frequent cause of inappropriate shocks in S-ICD patients. After invasive treatment for HOCM, there is a risk of developing intraventricular conduction delay and subsequent changes in QRS and T-wave morphology. This should be taken into consideration when ICD indication is evaluated in HOCM patients.

Cardioversion strategy impacts rate control during recurrences in patients with paroxysmal atrial fibrillation: A subanalysis of the RACE 7 ACWAS trial.

BACKGROUND: In the Rate Control versus Electrical Cardioversion Trial 7-Acute Cardioversion versus Wait and See, patients with recent-onset atrial fibrillation (AF) were randomized to either early or delayed cardioversion. AIM: This prespecified sub-analysis aimed to evaluate heart rate during AF recurrences after an emergency department (ED) visit identified by an electrocardiogram (ECG)-based handheld device. METHODS: After the ED visit, included patients (n = 437) were asked to use an ECG-based handheld device to monitor for recurrences during the 4-week follow-up period. 335 patients used the handheld device and were included in this analysis. Recordings from the device were collected and assessed for heart rhythm and rate. Optimal rate control was defined as a target resting heart rate of <110 beats per minute (bpm). RESULTS: In 99 patients (29.6%, mean age 67 ± 10 years, 39.4% female, median 6 [3-12] AF recordings) a total of 314 AF recurrences (median 2 [1-3] per patient) were identified during follow-up. The average median resting heart rate at recurrence was 100 ± 21 bpm in the delayed vs 112 ± 25 bpm in the early cardioversion group (p = .011). Optimal rate control was seen in 68.4% [21.3%-100%] and 33.3% [0%-77.5%] of recordings (p = .01), respectively. Randomization group [coefficient -12.09 (-20.55 to -3.63, p = .006) for delayed vs. early cardioversion] and heart rate on index ECG [coefficient 0.46 (0.29-0.63, p < .001) per bpm increase] were identified on multivariable analysis as factors associated with lower median heart rate during AF recurrences. CONCLUSION: A delayed cardioversion strategy translated into a favorable heart rate profile during AF recurrences.

Left Atrial Appendage Occlusion vs Standard of Care After Ischemic Stroke Despite Anticoagulation.

Importance: Patients with atrial fibrillation (AF) who have ischemic stroke despite taking oral anticoagulation therapy (OAT) have a very high risk of recurrence. Left atrial appendage occlusion (LAAO) is a mechanical stroke prevention strategy that may provide additional protection in patients with thromboembolic events under OAT. Objective: To compare percutaneous LAAO with continuing OAT alone regarding stroke prevention in patients with AF who had a thromboembolic event despite taking OAT. Design, Setting, and Participants: This cohort study was a propensity score-matched comparison of the STR-OAC LAAO cohort, an international collaboration of 21 sites combining patients from multiple prospective registries of patients who underwent LAAO between 2010 and 2022. STR-OAC LAAO cohort patients who had follow-up longer than 3 months were propensity score-matched to a previously published control cohort comprising patients from an established international collaboration of investigator-initiated prospective studies. This control cohort included patients with nonvalvular AF, recent ischemic stroke or transient ischemic attack, and follow-up longer than 3 months who were taking OAT before the index event. Analyses were adjusted for imbalances in gender, age, hypertension, diabetes, and CHA2 DS2-VASc score. Exposure: Left atrial appendage occlusion vs continuation of oral anticoagulation therapy alone (control group). Main Outcomes and Measures: The primary outcome was time to first ischemic stroke. Results: Four hundred thirty-three patients from the STR-OAC LAAO cohort (mean [SD] age, 72 [9] years; 171 [39%] females and 262 [61%] males; mean [SD] CHA2 DS2-VASc score, 5.0 [1.6]) were matched to 433 of 1140 patients (38%) from the control group. During 2-year follow-up, 50 patients experienced ischemic stroke: an annualized event rate of 2.8% per patient-year in the STR-OAC LAAO group vs 8.9% per patient-year in the control group. Left atrial appendage occlusion was associated with a lower risk of ischemic stroke (hazard ratio, 0.33; 95% CI, 0.19-0.58; P < .001) compared with the control group. After LAAO, OAT was discontinued in 290 patients (67%), and the remaining 143 patients (33%) continued OAT after LAAO as an adjunctive therapy. Conclusions and Relevance: In patients with nonvalvular AF and a prior thromboembolic event despite taking OAT, LAAO was associated with a lower risk of ischemic stroke compared with continued OAT alone. Randomized clinical trial data are needed to confirm that LAAO may be a promising treatment option for this population with a very high risk of stroke.

Left Atrial Appendage Occlusion in Patients With Anticoagulation Failure vs Anticoagulation Contraindication.

BACKGROUND: Left atrial appendage occlusion (LAAO) provides mechanical cardioembolic protection for atrial fibrillation (AF) patients who cannot use oral anticoagulation therapy (OAT). Patients with a thrombotic event despite OAT are at high risk for recurrence and may also benefit from LAAO. OBJECTIVES: This study sought to investigate the efficacy of LAAO in AF patients with a thrombotic event on OAT compared to: 1) LAAO in AF patients with a contraindication for OAT; and 2) historical data. METHODS: The international LAAO after stroke despite oral anticoagulation (STR-OAC LAAO) collaboration included patients who underwent LAAO because of thrombotic events on OAT. This cohort underwent propensity score matching and was compared to the EWOLUTION (Evaluating Real-Life Clinical Outcomes in Atrial Fibrillation Patients Receiving the WATCHMAN Left Atrial Appendage Closure Technology) registry, which represents patients who underwent LAAO because of OAT contraindications. The primary outcome was ischemic stroke. Event rates were compared between cohorts and with historical data without OAT, yielding relative risk reductions based on risk scores. RESULTS: Analysis of 438 matched pairs revealed no significant difference in the ischemic stroke rate between the STR-OAC LAAO and EWOLUTION cohorts (2.5% vs 1.9%; HR: 1.37; 95% CI: 0.72-2.61). STR-OAC LAAO patients exhibited a higher thromboembolic risk (HR: 1.71; 95% CI: 1.04-2.83) but lower bleeding risk (HR: 0.39; 95% CI: 0.18-0.88) compared to EWOLUTION patients. The mortality rate was slightly higher in EWOLUTION (4.3% vs 6.9%; log-rank P = 0.028). Relative risk reductions for ischemic stroke were 70% and 78% in STR-OAC LAAO and EWOLUTION, respectively, compared to historical data without OAT. CONCLUSIONS: LAAO in patients with a thrombotic event on OAT demonstrated comparable stroke rates to the OAT contraindicated population in EWOLUTION. The thromboembolic event rate was higher and the bleeding rate lower, reflecting the intrinsically different risk profile of both populations. Until randomized trials are available, LAAO may be considered in patients with an ischemic event on OAT.

Dielectric response as a novel marker for ablation lesion quality: Relation to conventional ablation parameters.

Background: The tissue response viewer (TRV) is a novel marker for ablation lesion quality that aims to classify lesions into transmural or nontransmural lesions (high or low dielectric response, HDR or LDR) using dielectric-based tissue assessment. The objective of this study was to gain insight in the TRV by relating its outcomes to conventional ablation parameters. Methods: Patients that had repeat ablation for atrial fibrillation with a dielectric imaging-based mapping system were enrolled. All ablation data were downloaded from the mapping system and analyzed to explore associations between TRV outcomes and other ablation parameters. Results: The cohort included 24 patients, in which 58 pulmonary veins and 8 superior vena cavas were targeted. A total of 388 energy applications were applied, resulting in 639 ablation points. The system classified 36% of ablation points as HDR and 44% as LDR. The system did not provide a dielectric response in 20%. The system's ability to provide a dielectric response was related to longer ablation duration and absence of dragging ablation. HDR (versus LDR) was multivariably associated with longer energy applications, higher mean ablation power, and lower wall thickness. Greater impedance drop was univariably associated with HDR. Conclusion: Outcomes of the TRV are associated with conventional ablation parameters (e.g., duration and power) but also local wall thickness. Catheter stability seems important for successful lesion assessment with the TRV. Further reduction of missing outcomes and validation of the tool are warranted before widespread use.