Atrial fibrillation ablation in practice: assessing CABANA generalizability

Use of Post-Acute Care Services and Readmissions After Acute Myocardial Infarction Complicated by Cardiac Arrest and Cardiogenic Shock

OBJECTIVE

To evaluate post-acute care utilization and readmissions after cardiac arrest (CA) and cardiogenic shock (CS) complicating acute myocardial infarction (AMI).

METHODS

With use of an administrative claims database, AMI patients from January 1, 2010, to May 31, 2018, were stratified into CA+CS, CA only, CS only, and AMI alone. Outcomes included 90-day post-acute care (inpatient rehabilitation or skilled nursing facility) utilization and 1-year emergency department visits and readmissions.

RESULTS

Of 163,071 AMI patients, CA+CS, CA only, and CS only were noted in 3965 (2.4%), 8221 (5.0%), and 6559 (4.0%), respectively. In-hospital mortality was noted in 10,686 (6.6%) patients: CA+CS, 1935 (48.8%); CA only, 2948 (35.9%); CS only, 1578 (24.1%); and AMI alone, 4225 (2.9%) (P<.001). Among survivors, post-acute care services were used in 67,799 (44.5%), with higher use in the CS+CA cohort (1310 [64.6%]; hazard ratio [HR], 1.19; 95% CI, 1.06 to 1.33; P=.003) and CA cohort (2738 [51.9%]; HR, 1.27; 95% CI, 1.20 to 1.35; P<.001) but not in the CS cohort (3048 [61.2%]; HR, 1.03; 95% CI, 0.97 to 1.11; P=.35) compared with the AMI cohort (60,703 [43.3%]). Compared with the AMI cohort (48,990 [35.0%]), patients with CS only (2,085 [41.9%]; HR, 1.16; 95% CI, 1.10 to 1.22; P<.001) but not those with CA+CS (724 [35.7%]; HR, 1.07; 95% CI, 0.98 to 1.17; P=.14) had higher rates of readmissions (P=.03). Readmissions were lower in those with CA (1,590 [30.2%]; HR, 0.94; 95% CI, 0.89 to 0.99). Repeated AMI, coronary artery disease, and heart failure were the most common readmission reasons. There were no differences for emergency department visits.

CONCLUSION

CA is associated with increased post-acute care use, whereas CS is associated with increased readmission risk in AMI survivors.

Association of outpatient ACE inhibitors and angiotensin receptor blockers and outcomes of acute respiratory illness: a retrospective cohort study

OBJECTIVES

Evaluate associations between ACE inhibitors (ACEis) and angiotensin receptor blockers (ARBs) and clinical outcomes in acute viral respiratory illness (AVRI).

DESIGN

Retrospective cohort analysis of claims data.

SETTING

The USA; 2018-2019 influenza season.

PARTICIPANTS

Main cohort: people with hypertension (HTN) taking an ACEi, ARB or other HTN medications, and experiencing AVRI. Falsification cohort: parallel cohort receiving elective knee or hip replacement.

MAIN OUTCOME MEASURES

Main cohort: hospital admission, intensive care unit, acute respiratory distress (ARD), ARD syndrome and all-cause mortality. Falsification cohort: complications after surgery and all-cause mortality.

RESULTS

The main cohort included 236 843 episodes of AVRI contributed by 202 629 unique individuals. Most episodes were in women (58.9%), 81.4% in people with Medicare Advantage and 40.3% in people aged 75+ years. Odds of mortality were lower in the ACEi (0.78 (0.74 to 0.83)) and ARB (0.64 (0.61 to 0.68)) cohorts compared with other HTN medications. On all other outcomes, people taking ARBs (but not ACEis) had a >10% reduction in odds of inpatient stays compared with other HTN medications.In the falsification analysis (N=103 353), both ACEis (0.89 (0.80 to 0.98)) and ARBs (0.82 (0.74 to 0.91)) were associated with decreased odds of complications compared with other HTN medications; ARBs (0.64 (0.47 to 0.87)) but not ACEis (0.79 (0.60 to 1.05)) were associated with lower odds of death compared with other HTN medications.

CONCLUSIONS

Outpatient use of ARBs was associated with better outcomes with AVRI compared with other medications for HTN. ACEis were associated with reduced risk of death, but with minimal or no reduction in risk of other complications. A falsification analysis conducted to provide context on the possible causal implications of these findings did not provide a clear answer. Further analysis using observational data will benefit from additional approaches to assess causal relationships between these drugs and outcomes in AVRI.

Discontinuation of oral anticoagulation and risk of stroke and death after ablation for typical atrial flutter: A nation-wide Danish cohort study

INTRODUCTION

Oral anticoagulation (OAC) is indicated for patients with atrial fibrillation (AF) and atrial flutter (AFL) with a CHA₂DS₂-VASc score ≥ 2 for men and ≥3 for women. This is regardless of successful catheter ablation for their arrhythmia. Studies have mainly focused on AF, and little is known regarding use of OAC in AFL patients following catheter ablation.

PURPOSE

To describe discontinuation of OAC in a national cohort of patients who have undergone first-time cavo-tricuspid isthmus ablation (CTIA) for AFL.

METHODS

We identified patients undergoing first-time CTIA during the period 2010-2016 using the Danish National Ablation Registry. Information on comorbidities and OAC use were gathered using the Danish National Patient Registry and the Danish National Prescription Registry. Patients were followed until March 1st, 2018.

RESULTS

We identified 2409 consecutive patients. Median age was 66 (IQR 58-72) years, and 1952 (81%) were men. During mean follow-up of 4 ± 1.7 years, 723 (30%) patients discontinued OAC. Patients discontinuing OAC were younger, had less comorbidity, and a lower CHA₂DS₂-VASc score. During follow-up, 252 (10%) patients died, and 112 (5%) patients had a stroke. Incidence of both these events increased with increasing age and CHA₂DS₂-VASc score. In adjusted analysis, we observed higher mortality (p < 0.0001) in patients discontinuing OAC, while stroke rate was not significantly higher (p = 0.21).

CONCLUSION

In this national cohort of patients who have undergone first-time CTIA, patients discontinuing OAC treatment were younger and had less comorbidities. Patients remain at elevated risk of death and stroke/TIA, increasing with their age and CHA₂DS₂-VASc score.

Reduction of mortality by catheter ablation in real-world atrial fibrillation patients with heart failure

Whether catheter ablation for atrial fibrillation (AF) improves survival and affects other outcomes in real-world heart failure (HF) patients is unclear. This study aimed to evaluate whether ablation reduces death, and other outcomes in real-world AF patients with HF. Among 834,735 patients with AF from 2006 to 2015 in the Korean National Health Insurance Service database, 3173 HF patients underwent AF ablation. Propensity score weighting was used to correct for differences between the groups. During median 54 months follow-up, the risk of all-cause death in ablated patients was less than half of that in patients with medical therapy (2.8 vs. 6.2 per 100 person-years; hazard ratio [HR] 0.42, 95% confidence interval [CI] 0.27–0.65, p < 0.001). Ablation was related with lower risk of cardiovascular death (HR 0.38, 95% CI 0.32–0.62, p < 0.001), HF admission (HR 0.39, 95% CI 0.33–0.46, p < 0.001) and stroke/systemic embolism (HR 0.44, 95% CI 0.37–0.53, p < 0.001). In subgroup analysis, the risk of all-cause death was reduced in most subgroups except in the elderly (≥ 75 years) and strictly anticoagulated patients. Ablation may be associated with reduced risk of all-cause death and cardiovascular death in real-world AF patients with HF, supporting the role of AF ablation in patients with HF.

Association Between Sex and Treatment Outcomes of Atrial Fibrillation Ablation Versus Drug Therapy: Results From the CABANA Trial

BACKGROUND

Among patients with atrial fibrillation (AF), women are less likely to receive catheter ablation and may have more complications and less durable results. Most information about sex-specific differences after ablation comes from observational data. We prespecified an examination of outcomes by sex in the 2204-patient CABANA trial (Catheter Ablation Versus Antiarrhythmic Drug Therapy for Atrial Fibrillation).

METHODS

CABANA randomized patients with AF age ≥65 years or <65 years with ≥1 risk factor for stroke to a strategy of catheter ablation with pulmonary vein isolation versus drug therapy with rate/rhythm control agents. The primary composite outcome was death, disabling stroke, serious bleeding, or cardiac arrest, and key secondary outcomes included AF recurrence.

RESULTS

CABANA randomized 819 (37%) women (ablation 413, drug 406) and 1385 men (ablation 695, drug 690). Compared with men, women were older (median age, 69 years versus 67 years for men), were more symptomatic (48% Canadian Cardiovascular Society AF Severity Class 3 or 4 versus 39% for men), had more symptomatic heart failure (42% with New York Heart Association Class ≥II versus 32% for men), and more often had a paroxysmal AF pattern at enrollment (50% versus 39% for men) (P<0.0001 for all). Women were less likely to have ancillary (nonpulmonary vein) ablation procedures performed during the index procedure (55.7% versus 62.2% in men, P=0.043), and complications from treatment were infrequent in both sexes. For the primary outcome, the hazard ratio for those who underwent ablation versus drug therapy was 1.01 (95% CI, 0.62-1.65) in women and 0.73 (95% CI, 0.51-1.05) in men (interaction P value=0.299). The risk of recurrent AF was significantly reduced in patients undergoing ablation compared with those receiving drug therapy regardless of sex, but the effect was greater in men (hazard ratio, 0.64 [95% CI, 0.51-0.82] for women versus hazard ratio, 0.48 [95% CI, 0.40-0.58] for men; interaction P value=0.060).

CONCLUSIONS

Clinically relevant treatment-related strategy differences in the primary and secondary clinical outcomes of CABANA were not seen between men and women, and there were no sex differences in adverse events. The CABANA trial results support catheter ablation as an effective treatment strategy for both women and men. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00911508.

Ablation Versus Drug Therapy for Atrial Fibrillation in Heart Failure: Results From the CABANA Trial

BACKGROUND

In patients with heart failure and atrial fibrillation (AF), several clinical trials have reported improved outcomes, including freedom from AF recurrence, quality of life, and survival, with catheter ablation. This article describes the treatment-related outcomes of the AF patients with heart failure enrolled in the CABANA trial (Catheter Ablation Versus Antiarrhythmic Drug Therapy for Atrial Fibrillation).

METHODS

The CABANA trial randomized 2204 patients with AF who were ≥65 years old or <65 years old with ≥1 risk factor for stroke at 126 sites to ablation with pulmonary vein isolation or drug therapy including rate or rhythm control drugs. Of these, 778 (35%) had New York Heart Association class >II at baseline and form the subject of this article. The CABANA trial's primary end point was a composite of death, disabling stroke, serious bleeding, or cardiac arrest.

RESULTS

Of the 778 patients with heart failure enrolled in CABANA, 378 were assigned to ablation and 400 to drug therapy. Ejection fraction at baseline was available for 571 patients (73.0%), and 9.3% of these had an ejection fraction <40%, whereas 11.7% had ejection fractions between 40% and 50%. In the intention-to-treat analysis, the ablation arm had a 36% relative reduction in the primary composite end point (hazard ratio, 0.64 [95% CI, 0.41-0.99]) and a 43% relative reduction in all-cause mortality (hazard ratio, 0.57 [95% CI, 0.33-0.96]) compared with drug therapy alone over a median follow-up of 48.5 months. AF recurrence was decreased with ablation (hazard ratio, 0.56 [95% CI, 0.42-0.74]). The adjusted mean difference for the AFEQT (Atrial Fibrillation Effect on Quality of Life) summary score averaged over the entire 60-month follow-up was 5.0 points, favoring the ablation arm (95% CI, 2.5-7.4 points), and the MAFSI (Mayo Atrial Fibrillation-Specific Symptom Inventory) frequency score difference was -2.0 points, favoring ablation (95% CI, -2.9 to -1.2).

CONCLUSIONS

In patients with AF enrolled in the CABANA trial who had clinically diagnosed stable heart failure at trial entry, catheter ablation produced clinically important improvements in survival, freedom from AF recurrence, and quality of life relative to drug therapy. These results, obtained in a cohort most of whom had preserved left ventricular function, require independent trial verification. Registration: URL: https://www.clinicaltrials.gov/ct2/show/NCT00911508; Unique identifier: NCT0091150.

Blood flow volume of left atrial appendage measured by magnetic resonance imaging is improved after radiofrequency catheter ablation of atrial fibrillation

INTRODUCTION

Hemodynamics of left atrial appendage (LAA) is an important factor for future risk of ischemic stroke in atrial fibrillation (AF) patients. Velocity encoded cardiac magnetic resonance imaging (VENC-MRI) can evaluate blood flow volume of LAA without any invasive procedures. We aimed to evaluate the association between radiofrequency catheter ablation (RFCA) and LAA hemodynamics measured by MRI.

METHODS AND RESULTS

Consecutive RFCA cases in a single arrhythmia center were retrospectively analyzed. A total of 3120 AF patients who underwent first RFCA were analyzed. Among these patients 360 patients had both pre- and post-RFCA VENC-MRI evaluation. Atrial fibrillation was non-paroxysmal in 174 (48.3%) patients. Mean VENC-MRI (ml/sec) was significantly improved after RFCA with 49.93 ± 32.92 and 72.00 ± 34.82 for pre- and post-RFCA, respectively. Patients with non-paroxysmal AF (∆VENC-MRI = 14.63 ± 40.67 vs. 30.03 ± 35.37; p < .001) and low pre-RFCA VENC-MRI (∆VENC-MRI = 17.19 ± 38.35 vs. 50.35 ± 29.12; p < .001) had significantly higher improvement in VENC-MRI. Those who experienced late recurrence before post-RFCA MRI had significantly less improvement in LAA flow volume (∆VENC-MRI = 15.55 ± 41.41 vs. 26.18 ± 36.77; p = .011). Late recurrence and pre-RFCA VENC-MRI were significantly associated with ∆VENC-MRI after adjusting covariates. Patients who were AF before RFCA but maintained sinus rhythm after RFCA showed greatest improvement in VENC-MRI.

CONCLUSION

Effective rhythm control through RFCA can be associated with significant improvement in LAA hemodynamics. Low pre-RFCA VENC-MRI and absence of late recurrence were associated with greater improvement in LAA hemodynamics.

Catheter-related complications and mortality of atrial fibrillation ablation following introduction of contact force-sensing technology

OBJECTIVES

Contact force-sensing catheters allow real-time catheter-tissue contact force monitoring during atrial fibrillation. These catheters were rapidly adopted into clinical practice following market introduction in 2014, but concerns have been raised regarding collateral damage such as esophageal injury. We sought to examine whether the introduction of force-sensing catheters was associated with a change in short-term and intermediate-term acute care use, complications and mortality following atrial fibrillation ablation.

DESIGN

Retrospective cohort analysis. We used inverse probability treatment weight matching to account for the differences in baseline characteristics between groups.

SETTING

We examined patients included in the OptumLabs Data Warehouse who underwent ablation for atrial fibrillation before (2011-2013) and after (2015-2017) the market introduction of contact force-sensing catheters.

MAIN OUTCOME MEASURES

We examined 30-day and 90-day rates of all-cause acute care use, including hospitalizations and emergency department visits, as well as death and hospitalization for catheter-related complications, including atrioesophageal fistula, pericarditis, cardiac tamponade/perforation and stroke/transient ischemic attack.

RESULTS

Our sample included 3470 and 5772 patients who underwent atrial fibrillation (AF) ablation before and after market introduction of contact force-sensing catheters, respectively. Complication rates were low and did not differ between the two periods (p>0.10 for each outcome). The 30-day and 90-day mortality was 0.1% and 0.3%, respectively after market introduction and unchanged from prior to 2014. The 90-day rates of all-cause acute care use decreased, from 27.0% in 2011-2013 to 23.9% in 2015-2017 (p<0.001).

CONCLUSIONS

AF ablation-related catheter complications and mortality are low and there has been no significant change following the introduction of force-sensing catheters.

Patient-reported outcomes and subsequent management in atrial fibrillation clinical practice: Results from the Utah mEVAL AF program

BACKGROUND

Atrial fibrillation (AF) significantly reduces health-related quality of life (HRQoL), previously measured in clinical trials using patient-reported outcomes (PROs). We examined AF PROs in clinical practice and their association with subsequent clinical management.

METHODS

The Utah My Evaluation (mEVAL) program collects the Toronto AF Symptom Severity Scale (AFSS) in AF outpatients at the University of Utah. Baseline factors associated with worse AF symptom score (range 0-35, higher is worse) were identified in univariate and multivariable analyses. Secondary outcomes included AF burden and AF healthcare utilization. We also compared subsequent clinical management at 6 months between patients with better versus worse AF HRQoL.

RESULTS

Overall, 1338 patients completed the AFSS symptom score, which varied by sex (mean 7.26 for males vs. 10.27 for females; p < .001), age (<65, 9.73; 65-74, 7.66; ≥75, 7.58; p < .001), heart failure (9.39 with HF vs. 7.67 without; p < .001), and prior ablation (7.28 with prior ablation vs. 8.84; p < .001). In multivariable analysis, younger age (mean difference 2.92 for <65 vs. ≥75; p < .001), female sex (mean difference 2.57; p < .001), pulmonary disease (mean difference 1.88; p < .001), and depression (mean difference 2.46; p < .001) were associated with higher scores. At 6-months, worse baseline symptom score was associated with the use of rhythm control (37.1% vs. 24.5%; p < .001). Similar cofactors and results were associated with increased AF burden and health care utilization scores.

CONCLUSIONS

AF PROs in clinical practice identify highly-symptomatic patients, corroborating findings in more controlled, clinical trials. Increased AFSS score correlates with more aggressive clinical management, supporting the utility of disease-specific PROs guiding clinical practice.

Keeping it Simple: Balloon Devices for Atrial Fibrillation Ablation Therapy

Atrial fibrillation is a common disease of increasing prevalence. Catheter ablation has evolved into an established therapeutic option that mainly aims to electrically isolate the pulmonary veins from atrial myocardium. The traditional method comprises point-by-point radiofrequency current ablation guided by electroanatomical mapping and has proven to be effective and safe in experienced hands. However, this approach is technically highly demanding and associated with a long learning curve, limiting its widespread utilization. To address these shortcomings, simplified ablation tools for pulmonary vein isolation are needed. In this context, balloon devices promise to ease the procedure by approaching the entire orifice of a targeted pulmonary vein in a single maneuver. This requires less catheter manipulation in the left atrium and often allows ablation of a large volume of tissue with a single application of ablative energy. Two balloon devices-one using cryoenergy, the other laser energy-have already been established in clinical routine and have demonstrated noninferiority when compared with radiofrequency ablation in large randomized trials. More balloon devices are on the verge of being introduced into clinical practice and bear the potential to expand the interventional electrophysiologist's armamentarium when treating atrial fibrillation. The authors review the use of the established balloon devices available for atrial fibrillation ablation and provide a detailed outlook on upcoming balloon technologies, including 3 different balloons utilizing radiofrequency energy as well as a novel cryoballoon.

Long-Term Outcomes of Acute Myocardial Infarction With Concomitant Cardiogenic Shock and Cardiac Arrest

This study sought to evaluate long-term mortality and major adverse cardiac and cerebrovascular events (MACCE) in patients with cardiac arrest (CA) and cardiogenic shock (CS) complicating acute myocardial infarction (AMI). This was a retrospective cohort study using an administrative claims database. AMI patients from January 1, 2010 to May 31, 2018 were stratified into CA + CS, CA only, CS only, and AMI alone cohorts. Outcomes of interest were long-term mortality and MACCE (death, AMI, cerebrovascular accident, unplanned revascularization) in AMI survivors. A total 163,071 AMI patients were included with CA + CS, CA only, and CS only in 2.4%, 5.0%, and 4.0%, respectively. The CA + CS cohort had higher rates of multiorgan failure, mechanical circulatory support use and less frequent coronary angiography use. In-hospital mortality was noted in 10,686 (6.6%) patients - CA + CS (48.8%), CA only (35.9%), CS only (24.1%), and AMI alone (2.9%; p < 0.001). Over 23.5 ± 21.7 months follow-up after hospital discharge, patients with CA + CS (hazard ratio [HR] 1.36 [95% confidence interval {CI} 1.19 to 1.55]), CA only (HR 1.16 [95% CI 1.08 to 1.25]), CS only (HR 1.39 [95% CI 1.29 to 1.50]) had higher all-cause mortality compared with AMI alone (all p < 0.001). Presence of CS, either alone (HR 1.22 [95% CI 1.16 to 1.29]; p < 0.001) or with CA (HR 1.18 [95% CI 1.07 to 1.29]; p < 0.001), was associated with higher MACCE compared with AMI alone. In conclusion, CA + CS, CA, and CS were associated with worse long-term survival. CA and CS continue to influence outcomes beyond the index hospitalization in AMI survivors.

Early Rhythm-Control Therapy in Patients with Atrial Fibrillation

BACKGROUND

Despite improvements in the management of atrial fibrillation, patients with this condition remain at increased risk for cardiovascular complications. It is unclear whether early rhythm-control therapy can reduce this risk.

METHODS

In this international, investigator-initiated, parallel-group, open, blinded-outcome-assessment trial, we randomly assigned patients who had early atrial fibrillation (diagnosed ≤1 year before enrollment) and cardiovascular conditions to receive either early rhythm control or usual care. Early rhythm control included treatment with antiarrhythmic drugs or atrial fibrillation ablation after randomization. Usual care limited rhythm control to the management of atrial fibrillation-related symptoms. The first primary outcome was a composite of death from cardiovascular causes, stroke, or hospitalization with worsening of heart failure or acute coronary syndrome; the second primary outcome was the number of nights spent in the hospital per year. The primary safety outcome was a composite of death, stroke, or serious adverse events related to rhythm-control therapy. Secondary outcomes, including symptoms and left ventricular function, were also evaluated.

RESULTS

In 135 centers, 2789 patients with early atrial fibrillation (median time since diagnosis, 36 days) underwent randomization. The trial was stopped for efficacy at the third interim analysis after a median of 5.1 years of follow-up per patient. A first-primary-outcome event occurred in 249 of the patients assigned to early rhythm control (3.9 per 100 person-years) and in 316 patients assigned to usual care (5.0 per 100 person-years) (hazard ratio, 0.79; 96% confidence interval, 0.66 to 0.94; P = 0.005). The mean (±SD) number of nights spent in the hospital did not differ significantly between the groups (5.8±21.9 and 5.1±15.5 days per year, respectively; P = 0.23). The percentage of patients with a primary safety outcome event did not differ significantly between the groups; serious adverse events related to rhythm-control therapy occurred in 4.9% of the patients assigned to early rhythm control and 1.4% of the patients assigned to usual care. Symptoms and left ventricular function at 2 years did not differ significantly between the groups.

CONCLUSIONS

Early rhythm-control therapy was associated with a lower risk of adverse cardiovascular outcomes than usual care among patients with early atrial fibrillation and cardiovascular conditions. (Funded by the German Ministry of Education and Research and others; EAST-AFNET 4 ISRCTN number, ISRCTN04708680; ClinicalTrials.gov number, NCT01288352; EudraCT number, 2010-021258-20.).

The implications of catheter ablation for solitary atrial flutter in preventing stroke risk: a nationwide population-based cohort study

AIMS

The implications of ablation for atrial fibrillation in preventing stroke are controversial, and no studies have investigated whether ablation prevents ischaemic stroke (IS) in atrial flutter (AFL).

METHODS AND RESULTS

This study analysed data contained in the Taiwan National Health Insurance Research Database for 16 765 patients with a first diagnosis of solitary AFL during 2001-2013. Eligible patients were divided into two groups according to whether or not they had received ablation. Propensity score matching (PSM) was performed to mitigate the effects of potential confounding factors. The primary outcome was occurrence of IS during follow-up. After 1:2 PSM, the analysis included 1037 patients in the ablation group and 2074 patients in the non-ablation group. The incidence of IS was lower in the ablation group compared to the non-ablation group [subdistribution hazard ratio (SHR) 0.61, 95% confidence interval (CI) 0.41-0.90] during the 2-year follow-up period but not thereafter (SHR 1.03, 95% CI 0.72-1.48). When grouping by stroke history, it revealed that ablation affected the incidence of stroke in patients without history of stroke (SHR 0.59, 95% CI 0.38-0.91) but not in patients with history of stroke. When each group was stratified by CHA2DS2-VASc score, ablation lowered the incidence of stroke in patients with CHA2DS2-VASc ≤3 (SHR 0.31, 95% CI 0.16-0.60) but not in patients with CHA2DS2-VASc ≥4 in the initial 2-year follow-up.

CONCLUSION

The different incidence of IS in patients with/without ablation indicates that ablation reduces the risk of IS in AFL patients.

Cardiac Electronic Devices: Future Directions and Challenges

Cardiovascular implantable electronic devices (CIEDs) are essential management options for patients with brady- and tachyarrhythmias or heart failure with concomitant optimal pharmacotherapy. Despite increasing technological advances, there are still gaps in the management of CIED patients, eg, the growing number of lead- and pocket-related long-term complications, including cardiac device–related infective endocarditis, requires the greatest care. Likewise, patients with CIEDs should be monitored remotely as a part of a comprehensive, holistic management approach. In addition, novel technologies used in smartwatches may be a convenient tool for long-term atrial fibrillation (AF) screening, especially in high-risk populations. Early detection of AF may reduce the risk of stroke and other AF-related complications. The objective of this review article was to provide an overview of novel technologies in cardiac rhythm–management devices and future challenges related to CIEDs.

Electrical Posterior Box Isolation in Persistent Atrial Fibrillation Changed to Paroxysmal Atrial Fibrillation: A Multicenter, Prospective, Randomized Study

BACKGROUND

Persistent atrial fibrillation (AF) can change to paroxysmal AF after antiarrhythmic drug medication and cardioversion. We investigated whether electrical posterior box isolation (POBI) may improve rhythm outcome of catheter ablation in those patient groups.

METHODS

We prospectively randomized 114 patients with persistent AF to paroxysmal AF (men, 75%; 59.8±9.9 years old) to circumferential pulmonary vein isolation (CPVI) alone group (n=57) and additional POBI group (n=57). Primary end point was AF recurrence after a single procedure, and secondary end points were recurrence pattern, cardioversion rate, and response to antiarrhythmic drugs.

RESULTS

After a mean follow-up of 23.8±10.2 months, the clinical recurrence rate did not significantly differ between the CPVI alone and additional POBI group (31.6% versus 28.1%; P=0.682; log-rank P=0.729). The recurrences as atrial tachycardias (5.3% versus 12.3%; P=0.134) and cardioversion rates (5.3% versus 10.5%; P=0.250) were not significantly different between the CPVI and POBI groups. At the final follow-up, sinus rhythm was maintained without antiarrhythmic drug in 52.6% of CPVI group and 59.6% of POBI group (P=0.450). No significant difference was found in major complication rates between the two groups (5.3% versus 1.8%; P=0.618), but the total ablation time was significantly longer in the POBI group (4187±952 versus 5337±1517 s; P<0.001).

CONCLUSIONS

In patients with persistent AF converted to paroxysmal AF by antiarrhythmic drug, the addition of POBI to CPVI did not improve the rhythm outcome of catheter ablation or influence overall safety, while leading to longer ablation time. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02176616.

[Therapeutic management of nonvalvular atrial fibrillation]

Atrial fibrillation (AF) is the most frequent persistent cardiac arrhythmia and is associated with an increased mortality. Therefore, an effective differential treatment of patients is mandatory. After a risk stratification oral anticoagulation (OAC) should be initiated depending on the individual stroke risk of each patient. Alternatively, in the presence of contraindications for OAC and an increased risk for bleeding and/or stroke, the implantation of a left atrial appendage closure device can be considered. Symptomatic patients should undergo a rhythm control strategy if possible. Based on the risk-benefit considerations, catheter ablation (CA) of AF plays an increasingly important role in establishing long-term medicinal rhythm control. A pulmonary vein isolation can lead to freedom from AF for 1 year in 70-80% of patients with paroxysmal AF (and approximately 50% in persistent AF). So far, a survival advantage of CA could only be shown in patients with heart failure, so that in most cases this is only a symptomatic treatment for improvement in the quality of life.

Generalizability of the CASTLE-AF trial: Catheter ablation for patients with atrial fibrillation and heart failure in routine practice

BACKGROUND

In the Catheter Ablation for Atrial Fibrillation with Heart Failure (CASTLE-AF) trial, catheter ablation reduced the risk of death and heart failure (HF) hospitalization in patients with atrial fibrillation and HF by 40%.

OBJECTIVES

The study aimed to assess the generalizability of CASTLE-AF to routine clinical practice.

METHODS

Using a large US administrative database, we identified 289,831 patients with atrial fibrillation and HF treated with ablation (n = 7465) or medical therapy alone (n = 282,366) from January 1, 2008, through August 31, 2018. Patients were divided into 3 groups on the basis of trial eligibility: (1) eligible for CASTLE-AF, (2) failing to meet the inclusion criteria, and (3) meeting at least 1 of the exclusion criteria. Propensity score overlap weighting was used to balance ablated and drug-treated patients on 90 baseline characteristics. Cox proportional hazards regression was used to compare ablation with medical therapy for the primary outcome of a composite end point of all-cause mortality and HF hospitalization.

RESULTS

Only 7.8% of patients would have been eligible for the trial; 91.0% failed to meet the trial inclusion criteria; and 15.5% met the exclusion criteria. Ablation was associated with a lower risk of the primary outcome in the overall cohort (hazard ratio [HR] 0.81; 95% confidence interval [CI] 0.76-0.87; P < .001), in the trial-eligible cohort (HR 0.82; 95% CI 0.70-0.96; P = .01), and in patients who failed to meet inclusion criteria (HR 0.79; 95% CI 0.73-0.86; P < .001) but not in patients who met the exclusion criteria (HR 0.97; 95% CI 0.81-1.17). The relative risk reduction was consistent regardless of whether patients had HF with reduced left ventricular ejection fraction.

CONCLUSION

The benefit associated with ablation appears to be more modest in practice than that reported in the CASTLE-AF trial.

Utilization and Complications of Catheter Ablation for Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy

Background

Atrial fibrillation (AF) is common and bears a major clinical impact in patients with hypertrophic cardiomyopathy (HCM). We aimed to investigate the use and real‐world safety of catheter ablation for AF in patients with HCM.

Methods and Results

We drew data from the US National Inpatient Sample to identify cases of AF ablation in HCM patients between 2003 and 2015. Sociodemographic and clinical data were collected, and incidence of catheter ablation complications, mortality, and length of stay were analyzed, including trends between the early (2003–2008) and later (2009–2015) study years. Among a weighted total of 1563 catheter ablation cases in patients with HCM, the median age was 62 (interquartile range, 52–72), 832 (53.2%) were male, and 1150 (73.6%) were white. The average annual volume of AF ablations in patients with HCM doubled between the early and the later study period (79–156). At least 1 complication occurred in 16.1% of cases, and the in‐hospital mortality rate was 1%. Cardiac and pericardial complications declined from 8.8% to 2.3% and from 2.8% to 0.9%, respectively, between the early and the later study years (P<0.01). Independent predictors of complications included female sex (odds ratio [OR], 4.81; 95% CI, 2.72–8.51), diabetes mellitus (OR, 6.57; 95% CI, 2.68–16.09) and obesity (OR, 3.82; 95% CI, 1.61–9.06).

Conclusions

Despite some decline in procedural complications over the years, catheter ablation for AF is still associated with a relatively high periprocedural morbidity and even mortality in patients with HCM. This emphasizes the importance of careful clinical consideration, by an experienced electrophysiologist, in referring patients with HCM for an AF ablation.

Relation of Frailty to Outcomes After Catheter Ablation of Atrial Fibrillation

Catheter ablation for atrial fibrillation (AF) improves outcomes compared with medical treatment alone. Risk stratification for outcomes following AF ablation remains an important area of uncertainty. This analysis evaluated the association between frailty and outcomes following AF ablation. We evaluated US inpatients receiving AF ablation between January 1, 2016 and December 1, 2016 using Medicare fee-for-service billing codes. Diagnosis codes were used to calculate patients' Hospital Frailty Risk Score, with the cohort divided according to established cut-points of low (<5), intermediate (5 to 15), and high (>15) risk for frailty. The primary outcome was survival. Among 5,070 in patients treated with catheter ablation (mean age 74.9 ± 6.8 years, 51.1% female), 38.6% were defined as frail with a Hospital Frailty Risk Score >5, including 8.3% at high risk. Mortality rates (up to 630 days) were 5.8% in the low-risk group, 23.4% in the intermediate-risk group, and 42.2% in the high-risk group (log-rank p values <0.001 for comparison between categories). In restricted cubic spline regression analysis, the adjusted hazard ratios for long-term mortality monotonically increased with increasing values of the Hospital Frailty Risk Score (adjusted hazard ratio 1.065, 95% confidence interval 1.054 to 1.077). In secondary end points, frailty was independently associated with length of stay, postprocedure 30-day mortality, 30-day readmission and postdischarge 30-day mortality rates. In conclusion, frailty as assessed by a claims-based score is common in inpatient recipients of AF ablation, and provides risk stratification for mortality and other key clinical outcomes.

A mesh-type flexible tip catheter vs a contact force catheter for catheter ablation of atrial fibrillation: A prospective nonrandomized 1:1 matched study

INTRODUCTION

Mesh-type flexible tip (MFT) catheters allow clinicians to safely generate large radiofrequency lesions during catheter ablation of atrial fibrillation (AF), while contact force (CF) catheters provide better catheter-tissue contact. We compared the clinical outcomes of catheter ablation of AF using MFT and CF catheters in a prospective, nonrandomized manner.

METHODS

We prospectively assigned 217 patients with AF (paroxysmal AF 73.5%; male 69.1%; 59.9 ± 10.7 years old) at a 1:1 ratio to ablation with MFT catheters (FlexAbility) or CF catheters (TactiCath). The primary endpoint was AF recurrence after a single procedure; the secondary endpoint was a response to antiarrhythmic drugs.

RESULTS

After a mean follow-up of 22.3 ± 4.4 months, the clinical recurrence rate did not significantly differ between the two study groups (29.7% vs 30.2%; P = .941) (log-rank P = .838). The recurrence rate for atrial tachycardias (30.3% vs 9.7%; P = .035) and cardioversion rates (8.1% vs 1.9%; P = .024) were higher in the MFT group than CF group. At the final follow-up, sinus rhythm was maintained without antiarrhythmic drugs in 57.7% of the MFT group and 40.6% of the CF group (P = .010). No significant difference was found in the major complication rates between the two groups (0.9% vs 5.7%), although the ablation time was significantly longer in the MFT group (4192.1 ± 1080.2  vs 3583.8 ± 977.2 seconds; P < .001).

CONCLUSION

MFT and CF catheters had similar effectiveness in achieving AF rhythm control during catheter ablation, and there was no significant difference between the two catheters with regard to overall safety.

Impact of atrial fibrillation catheter ablation on mortality, stroke, and heart failure hospitalizations: A meta-analysis

BACKGROUND

The impact of atrial fibrillation catheter ablation (AFCA) on hard clinical endpoints remains controversial.

OBJECTIVE

Our aim was to conduct a random-effect model meta-analysis on efficacy data from high-quality large matched database/registry studies and randomized clinical trials. We compared long-term all-cause mortality, stroke, and hospitalization for heart failure in patients undergoing AFCA vs patients treated with medical therapy alone (rhythm and/or rate control medications) in a general AF population.

METHODS AND RESULTS

PubMed/MEDLINE and Embase databases were screened and a total of nine studies were selected (one randomized clinical trial-CABANA-and eight large matched population studies). A total of 241 372 patients (27 711 in the ablation group, 213 661 in the nonablation group) were included. After a median follow-up of 3.5 years, AFCA decreased the risk of mortality (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.54-0.72; I² = 54%; number needed to treat [NNT] = 28), stroke (HR, 0.63; 95% CI, 0.56-0.70; I²  = 23%; NNT = 59) and hospitalization for heart failure (HR, 0.64; 95% CI, 0.51-0.80; I²  = 28%; NNT = 33) compared with AF patients treated with medical therapy alone.

CONCLUSION

Based on the currently available efficacy and effectiveness evidence, AFCA significantly reduces the risk of death, stroke, and hospitalization compared with medical therapy alone.

Treatment of Atrial Fibrillation Using Ablation Index-Guided Contact Force Ablation: A Matching-Adjusted Indirect Comparison to Cryoballoon Ablation

Introduction

Ablation Index, also known as VISITAG SURPOINT™, is a novel lesion-quality marker that improves outcomes in radiofrequency (RF) catheter ablation of atrial fibrillation (AF). There is no direct evidence on the comparative effectiveness of RF ablation with Ablation Index and cryoballoon (CB). The objective of the present study was to conduct a matching-adjusted indirect comparison (MAIC) using individual patient-level data (IPD) to compare the effectiveness of RF ablation with Ablation Index to that of CB on recurrence of atrial arrhythmias 12 months after catheter ablation in patients with paroxysmal AF (PAF).

Methods

Individual patient-level data for RF ablation with Ablation Index were obtained from two studies: Solimene et al. [J Interv Card Electrophysiol 54(1):9–15, 2019] and Hussein et al. [J Cardiovasc Electrophysiol 28(9):1037–1047, 2017]. Comparable CB studies identified from a systematic literature review were pooled. Prognostic variables for adjustment were ranked a priori by several practicing electrophysiologists. In the absence of a common treatment arm between the Ablation Index and CB studies, an unanchored MAIC was conducted. Primary analysis compared the Solimene et al. study to pooled CB studies. A secondary analysis compared pooled RF ablation with Ablation Index studies to pooled CB studies. Several scenario and sensitivity analyses were conducted.

Results

Primary analyses showed statistically significant reductions in the rate of arrhythmia recurrence with RF ablation with Ablation Index compared to CB in unmatched, unadjusted (HR 0.50, 95% CI 0.27–0.95) and matched (0.42, 0.21–0.86) analyses. Greater reductions in the rate of arrhythmia recurrence that favored RF ablation with Ablation Index were observed after matching and adjusting for age (0.41, 0.20–0.85), age and left ventricular ejection fraction (0.37, 0.16–0.88), and age, sex, and left ventricular ejection fraction (0.30, 0.13–0.71). Secondary and sensitivity analyses showed similar reductions.

Conclusions

Radiofrequency ablation with Ablation Index was associated with reductions in recurrence of atrial arrhythmias at 12 months compared to CB in unmatched and unadjusted, matched, and matched and adjusted comparisons.

Electronic Supplementary Material

The online version of this article (10.1007/s12325-019-01173-4) contains supplementary material, which is available to authorized users.

Enhanced cardiomyocyte reactive oxygen species signaling promotes ibrutinib-induced atrial fibrillation

Atrial fibrillation (AF) occurs in up to 11% of cancer patients treated with ibrutinib. The pathophysiology of ibrutinib promoted AF is complicated, as there are multiple interactions involved; the detailed molecular mechanisms underlying this are still unclear. Here, we aimed to determine the electrophysiological and molecular mechanisms of burst-pacing-induced AF in ibrutinib-treated mice. The results indicated differentially expressed proteins in ibrutinib-treated mice, identified through proteomic analysis, were found to play a role in oxidative stress-related pathways. Finally, treatment with an inhibitor of NADPH oxidase (NOX) prevented and reversed AF development in ibrutinib-treated mice. It was showed that the related protein expression of reactive oxygen species (ROS) in the ibrutinib group was significantly increased, including NOX2, NOX4, p22-phox, XO and TGF-β protein expression. It was interesting that ibrutinib group also significantly increased the expression of ox-CaMKII, p-CaMKII (Thr-286) and p-RyR2 (Ser2814), causing enhanced abnormal sarcoplasmic reticulum (SR) Ca²⁺ release and mitochondrial structures, as well as atrial fibrosis and atrial hypertrophy in ibrutinib-treated mice, and apocynin reduced the expression of these proteins. Ibrutinib-treated mice were also more likely to develop AF, and AF occurred over longer periods. In conclusion, our study has established a pathophysiological role for ROS signaling in atrial cardiomyocytes, and it may be that ox-CaMKII and p-CaMKII (Thr-286) are activated by ROS to increase AF susceptibility following ibrutinib treatment. We have also identified the inhibition of NOX as a potential novel AF therapy approach.

Cabins, castles, and constant hearts: rhythm control therapy in patients with atrial fibrillation

Recent innovations have the potential to improve rhythm control therapy in patients with atrial fibrillation (AF). Controlled trials provide new evidence on the effectiveness and safety of rhythm control therapy, particularly in patients with AF and heart failure. This review summarizes evidence supporting the use of rhythm control therapy in patients with AF for different outcomes, discusses implications for indications, and highlights remaining clinical gaps in evidence. Rhythm control therapy improves symptoms and quality of life in patients with symptomatic AF and can be safely delivered in elderly patients with comorbidities (mean age 70 years, 3-7% complications at 1 year). Atrial fibrillation ablation maintains sinus rhythm more effectively than antiarrhythmic drug therapy, but recurrent AF remains common, highlighting the need for better patient selection (precision medicine). Antiarrhythmic drugs remain effective after AF ablation, underpinning the synergistic mechanisms of action of AF ablation and antiarrhythmic drugs. Atrial fibrillation ablation appears to improve left ventricular function in a subset of patients with AF and heart failure. Data on the prognostic effect of rhythm control therapy are heterogeneous without a clear signal for either benefit or harm. Rhythm control therapy has acceptable safety and improves quality of life in patients with symptomatic AF, including in elderly populations with stroke risk factors. There is a clinical need to better stratify patients for rhythm control therapy. Further studies are needed to determine whether rhythm control therapy, and particularly AF ablation, improves left ventricular function and reduces AF-related complications.

Outcomes and Anticoagulation Use After Catheter Ablation for Atrial Fibrillation

Background:

Studies evaluating the effects of atrial fibrillation (AF) catheter ablation versus antiarrhythmic therapy on outcomes have shown mixed results. In addition, guidelines recommend continuing oral anticoagulation (OAC) after ablation for those at risk of stroke, but real-world data are lacking.

Methods:

We evaluated outcomes including death, myocardial infarction, stroke or systemic embolism, intracranial bleeding, major bleeding, and hospitalization in patients undergoing AF ablation compared with a propensity score matched cohort of patients treated with anti-arrhythmic medications only in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation registries. Cox proportional hazards regression was performed to evaluate the association between AF ablation and outcomes. We then evaluated patterns of treatment with OAC among AF ablation patients.

Results:

Among 21 595 patients, 1190 (6%) underwent de novo AF ablation. Our propensity score-matched cohort included 1087 patients who underwent AF ablation matched 1:1 with 1087 patients treated with antiarrhythmic medications only. There were no significant differences in the risk of all-cause and cardiovascular death, and most other major adverse cardiovascular and neurological events. AF catheter ablation was associated with an increased risk of all-cause hospitalization during follow-up (hazard ratio, 1.24 [95% CI, 1.05–1.46]), particularly in the first 3 months (the standard blanking period) after the procedure. Among those who underwent AF ablation with a CHA 2 DS 2 VASc score ≥2 for men and ≥3 for women, 23% had OAC discontinued after ablation. Among those who discontinued OAC, the median time to discontinuation was 6.2 months.

Conclusions:

In this large US national registry, we found no difference in adjusted rates of cardiovascular or all-cause death between patients treated with AF catheter ablation and antiarrhythmic medications only. Notably, discontinuation of OAC after ablation remains relatively common despite guideline recommendations for continued stroke prevention therapy in patients at risk of stroke.

Endocardial contact mapping of the left atrial appendage in persistent atrial fibrillation

INTRODUCTION

Isolation of the left atrial appendage (LAA) is often performed in persistent atrial fibrillation (AF). Propagation patterns in the LAA during AF remain to be elucidated. We sought to characterize propagation patterns in the LAA during AF in persistent AF.

METHODS

Persistent AF patients undergoing catheter ablation were studied. Pulmonary vein isolation (PVI) was performed during continuous AF. If AF was not terminated by PVI, bi-atrial mapping was performed using a multi-electrode catheter during AF. Maps were collected at each site for 30 seconds and analyzed offline with a novel software, CARTOFINDER. This software made automatic determinations of whether activation was focal or rotational. The left atrium (LA) was divided into five regions, of which the LAA was one, and the right atrium (RA) into three.

RESULTS

Eighty patients were studied (62 ± 10 years, 65 males). On average, 9.6 ± 2.2 and 4.1 ± 1.2 maps were created in the LA and RA, respectively. The LAA was mapped in 70 patients, resulting in 85 maps. In the LAA, activation was identified as focal more often than rotational (64 [91%] vs 10 [14%] patients, P < .001), seven patients displayed both. The number of focal activation events was greatest in the LAA (28.5 events/30 seconds [interquartile range, 15-54]) of the eight atrial regions. During focal activation, sites designated as earliest activation frequently covered a wide area, rather than being localized to a discrete site (5.4 ± 3.1 electrodes).

CONCLUSIONS

The results of this study suggest that focal activation is a major mechanism underlying the arrhythmogenicity of the LAA in persistent AF.

Reverse Remodeling of the Mitral Valve Complex After Radiofrequency Catheter Ablation for Atrial Fibrillation

Background:

Mitral regurgitation is frequently complicated with atrial fibrillation without apparent organic changes in the leaflet, which occasionally improves after successful radiofrequency catheter ablation. We aimed to evaluate a possible geometric effect of radiofrequency catheter ablation on the mitral valve apparatus.

Methods:

Forty-three consecutive patients who underwent successful catheter ablation for persistent atrial fibrillation (maintaining sinus rhythm for 6 months after their procedure) were examined by serial real-time 3-dimensional transesophageal echocardiography before and 6 months after catheter ablation. Mitral valve complex geometry was measured using dedicated software for 3-dimensional transesophageal echocardiography.

Results:

Mitral valve apparatus showed significant reverse remodeling along with left atrial reverse remodeling 6 months after successful catheter ablation (50.5 [39.2–61.0] versus 36.4 [28.9–43.1] mL/m 2 ; P <0.001). The degree of mitral regurgitation decreased in a majority of patients (mitral regurgitation jet area; 1.83 [0.78–3.09] versus 0.77 [0.36–1.47] cm 2 ; P <0.001). Annular area significantly decreased (5.32±0.91 versus 4.73±0.76 cm 2 /m 2 ; P <0.001) in both anterior-posterior and medial-lateral directions. Mitral annular contraction significantly recovered after maintaining sinus rhythm for 6 months (7.51 [4.82–9.62]% versus 9.71 [6.27–13.85]%; P =0.008). There were no significant changes in tenting volume or tenting height (0.46 [0.27–0.89] versus 0.51 [0.32–0.72] mL/m 2 , P =0.744; 2.34 [1.75–3.48] versus 2.76 [1.99–3.08] mm/m 2 , P =0.717). The leaflet surface area also significantly decreased after catheter ablation (5.74 [5.01–6.33] versus 5.19 [4.63–5.64] cm 2 /m 2 ; P <0.001).

Conclusions:

Maintaining sinus rhythm after successful catheter ablation promotes reverse remodeling in the mitral valve apparatus and improves so-called atrial functional mitral regurgitation. The positive geometric effect of catheter ablation would be expected to be a possible contributor to better outcomes in patients with atrial fibrillation, in addition to the postprocedural freedom from rhythm disturbance.

Rhythm control for patients with atrial fibrillation complicated with heart failure in the contemporary era of catheter ablation: a stratified pooled analysis of randomized data

Aims

The optimal treatment for patients with atrial fibrillation (AF) and heart failure (HF) has been a subject of debate for years. We aimed to evaluate the efficacy and safety of rhythm control strategy in patients with AF complicated with HF regarding hard clinical endpoints.

Methods and results

Up-to-date randomized data comparing rhythm control using antiarrhythmic drugs (AADs) vs. rate control (Subset A) or rhythm control using catheter ablation vs. medical therapy (Subset B) in AF and HF patients were pooled. The primary outcomes were all-cause mortality, re-hospitalization, stroke, and thromboembolic events. A total of 11 studies involving 3598 patients were enrolled (Subset A: 2486; Subset B: 1112). As compared with medical rate control, the AADs rhythm control was associated with similar all-cause mortality [odds ratio (OR): 0.96, P = 0.65], significantly higher rate of re-hospitalization (OR: 1.25, P = 0.01), and similar rate of stroke and thromboembolic events (OR: 0.91, P = 0.76,); however, as compared with medical therapy, catheter ablation rhythm control was associated with significantly lower all-cause mortality (OR: 0.51, P = 0.0003), reduced re-hospitalization rate (OR: 0.44, P = 0.003), similar rate of stroke events (OR: 0.59, P = 0.27), greater improvement in left ventricular ejection fraction [weighted mean difference (WMD): 6.8%, P = 0.0004], lower arrhythmia recurrence (29.6% vs. 80.1%, OR: 0.04, P &lt; 0.00001), and greater improvement in quality of life (Minnesota Living with Heart Failure Questionnaire score) (WMD: −9.1, P = 0.007).

Conclusion

Catheter ablation as rhythm control strategy substantially improves survival rate, reduces re-hospitalization, increases the maintenance rate of sinus rhythm, contributes to preserve cardiac function, and improves quality of life for AF patients complicated with HF.

Novel approaches to the management of chronic systolic heart failure: future directions and unanswered questions

Despite improvements in outcomes in the last few decades for heart failure (HF) with reduced ejection fraction (HFrEF), there still remains a need for novel therapies as many patients incompletely recover with existing therapies and progress to advanced HF. In this review, we will discuss recent advances in the management of HFrEF with a focus on upcoming therapies that hold the greatest promise for clinical use. We will discuss novel pharmacological therapies and areas of uncertainty with existing therapies. We will also discuss the potential utility and controversy surrounding novel interventions for HF such as percutaneous mitral valve repair, atrial fibrillation ablation, and other emerging interventions with positive signals for benefit in HFrEF. Finally, we will summarize the current state of stem cell and gene therapy for HFrEF and future directions.

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Effect of Catheter Ablation vs Antiarrhythmic Drug Therapy on Mortality, Stroke, Bleeding, and Cardiac Arrest Among Patients With Atrial Fibrillation: The CABANA Randomized Clinical Trial

IMPORTANCE

Catheter ablation is effective in restoring sinus rhythm in atrial fibrillation (AF), but its effects on long-term mortality and stroke risk are uncertain.

OBJECTIVE

To determine whether catheter ablation is more effective than conventional medical therapy for improving outcomes in AF.

DESIGN, SETTING, AND PARTICIPANTS

The Catheter Ablation vs Antiarrhythmic Drug Therapy for Atrial Fibrillation trial is an investigator-initiated, open-label, multicenter, randomized trial involving 126 centers in 10 countries. A total of 2204 symptomatic patients with AF aged 65 years and older or younger than 65 years with 1 or more risk factors for stroke were enrolled from November 2009 to April 2016, with follow-up through December 31, 2017.

INTERVENTIONS

The catheter ablation group (n = 1108) underwent pulmonary vein isolation, with additional ablative procedures at the discretion of site investigators. The drug therapy group (n = 1096) received standard rhythm and/or rate control drugs guided by contemporaneous guidelines.

MAIN OUTCOMES AND MEASURES

The primary end point was a composite of death, disabling stroke, serious bleeding, or cardiac arrest. Among 13 prespecified secondary end points, 3 are included in this report: all-cause mortality; total mortality or cardiovascular hospitalization; and AF recurrence.

RESULTS

Of the 2204 patients randomized (median age, 68 years; 37.2% female; 42.9% had paroxysmal AF and 57.1% had persistent AF), 89.3% completed the trial. Of the patients assigned to catheter ablation, 1006 (90.8%) underwent the procedure. Of the patients assigned to drug therapy, 301 (27.5%) ultimately received catheter ablation. In the intention-to-treat analysis, over a median follow-up of 48.5 months, the primary end point occurred in 8.0% (n = 89) of patients in the ablation group vs 9.2% (n = 101) of patients in the drug therapy group (hazard ratio [HR], 0.86 [95% CI, 0.65-1.15]; P = .30). Among the secondary end points, outcomes in the ablation group vs the drug therapy group, respectively, were 5.2% vs 6.1% for all-cause mortality (HR, 0.85 [95% CI, 0.60-1.21]; P = .38), 51.7% vs 58.1% for death or cardiovascular hospitalization (HR, 0.83 [95% CI, 0.74-0.93]; P = .001), and 49.9% vs 69.5% for AF recurrence (HR, 0.52 [95% CI, 0.45-0.60]; P < .001).

CONCLUSIONS AND RELEVANCE

Among patients with AF, the strategy of catheter ablation, compared with medical therapy, did not significantly reduce the primary composite end point of death, disabling stroke, serious bleeding, or cardiac arrest. However, the estimated treatment effect of catheter ablation was affected by lower-than-expected event rates and treatment crossovers, which should be considered in interpreting the results of the trial.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00911508.