Geographic and racial representation and reported success rates of studies of catheter ablation for atrial fibrillation: Findings from the SMASH-AF meta-analysis study cohort

Efficacy and safety of a novel hexaspline pulsed field ablation system in patients with paroxysmal atrial fibrillation: the PLEASE-AF study

AIMS

Pulsed field ablation (PFA) is an emerging non-thermal ablative modality demonstrating considerable promise for catheter ablation of atrial fibrillation (AF). However, these PFA trials have almost universally included only Caucasian populations, with little data on its effect on other races/ethnicities. The PLEASE-AF trial sought to study the 12-month efficacy and the safety of a multi-electrode hexaspline PFA catheter in treating a predominantly Asian/Chinese population of patients with drug-refractory paroxysmal AF.

METHODS AND RESULTS

Patients underwent pulmonary vein (PV) isolation (PVI) by delivering different pulse intensities at the PV ostium (1800 V) and atrium (2000 V). Acute success was defined as no PV potentials and entrance/exit conduction block of all PVs after a 20-min waiting period. Follow-up at 3, 6, and 12 months included 12-lead electrocardiogram and 24-h Holter examinations. The primary efficacy endpoint was 12-month freedom from any atrial arrhythmias lasting at least 30 s. The cohort included 143 patients from 12 hospitals treated by 28 operators: age 60.2 ± 10.0 years, 65.7% male, Asian/Chinese 100%, and left atrial diameter 36.6 ± 4.9 mm. All PVs (565/565, 100%) were successfully isolated. The total procedure, catheter dwell, total PFA application, and total fluoroscopy times were 123.5 ± 38.8 min, 63.0 ± 30.7 min, 169.7 ± 34.6 s, and 27.3 ± 10.1 min, respectively. The primary endpoint was observed in 124 of 143 patients (86.7%). One patient (0.7%) developed a small pericardial effusion 1-month post-procedure, not requiring intervention.

CONCLUSION

The novel hexaspline PFA catheter demonstrated universal acute PVI with an excellent safety profile and promising 12-month freedom from recurrent atrial arrhythmias in an Asian/Chinese population with paroxysmal AF.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05114954.

Atrial fibrillation bleeding risk and prediction while treated with direct oral anticoagulants in warfarin-naïve or warfarin-experienced patients

Background

In patients with atrial fibrillation (AF) treated with direct oral anticoagulants (DOAC), bleeding risk scores provide only modest discrimination for major or intracranial bleeding. However, warfarin experience may impact HAS‐BLED  (Hypertension, Abnormal renal/liver function, Stroke, Bleeding history or predisposition, Labile international normalized ratio, Elderly (>65 years), Drugs/alcohol concomitantly) score performance in patients evaluated for DOACs, as HAS‐BLED was derived and validated in warfarin cohorts.

Methods

We performed a retrospective cohort study of patients prescribed DOAC for AF in the Veterans Health Administration between 2010 and 2017. We determined modified HAS‐BLED score discrimination and calibration for bleeding, for patients treated with DOAC, stratified by prior warfarin exposure. We also determined the association between DOAC–warfarin‐naïve status to bleeding (nonintracranial and intracranial) with DOAC–warfarin‐experienced patients as reference.

Results

The DOAC analysis cohort included 100, 492 patients with AF (age [mean ± SD]: 72.9 ± 9.6 years; 1.7% female; 90.1% White), of which 26, 760 patients (26.6%) and 73, 732 patients (73.4%) were warfarin experienced or naïve, respectively. HAS‐BLED discrimination for bleeds was modest for patients treated with DOAC, regardless of prior warfarin experience (concordance statistics: 0.53–0.59). For DOAC–warfarin‐naïve patients, as compared to DOAC–warfarin‐experienced patients, adjusted risk of intracranial bleeding was lower, while risk of nonintracranial bleeding was higher (intracranial bleeding propensity adjusted with inverse probability of treatment weights [IPTWs]: hazard ratio [HR]: 0.86, 95% confidence interval [CI]: 0.78–0.95, p = .0040) (nonintracranial bleeding propensity adjusted with IPTW: HR: 1.15, 95% CI: 1.11–1.19, p < .0001).

Conclusion

Patients’ modified HAS‐BLED score at the time of DOAC initiation, regardless of prior warfarin use, provided only modest discrimination for intracranial and nonintracranial bleeds. These data argue against maintaining DOAC eligible patients on warfarin therapy regardless of modified HAS‐BLED score.

Sex Differences in Ablation Strategy, Lesion Sets, and Complications of Catheter Ablation for Atrial Fibrillation: An Analysis From the GWTG-AFIB Registry

BACKGROUND

When presenting for atrial fibrillation (AF) ablation, women, compared with men, tend to have more nonpulmonary vein triggers and advanced atrial disease. Whether this informs differences in AF ablation strategy is not well described. We aimed to characterize ablation strategy and complications by sex, using the Get With The Guidelines-AF registry.

METHODS

From the Get With The Guidelines-AF registry ablation feature, we included patients who underwent initial AF ablation procedure between January 7, 2016, and December 27, 2019. Patients were stratified based on AF type (paroxysmal versus nonparoxysmal) and sex. We compared patient demographics, ablation strategy, and complications by sex.

RESULTS

Among 5356 patients from 31 sites who underwent AF ablation, 1969 were women (36.8%). Women, compared with men, were older (66.8±9.6 versus 63.4±10.6, P<0.0001) and were more likely to have paroxysmal AF (59.4% versus 49.5%, P<0.0001). In women with nonparoxysmal AF, left atrial linear ablation was more frequent (roof line: 53.9% versus 45.3%, P=0.0002; inferior mitral isthmus line: 10.2% versus 7.0%, P=0.01; floor line: 46.1% versus 40.6%, P=0.02) than in men. In multivariable analysis, the association between patient sex and complications from ablation was not statistically significant.

CONCLUSIONS

In this US wide AF ablation quality improvement registry, women with nonparoxysmal AF were more likely to receive adjunctive lesion sets compared with men. These findings suggest that patient sex may inform ablation strategy in ways that may not be strongly supported by evidence and emphasize the need to clarify optimal ablation strategies by sex.

Ablation Versus Drug Therapy for Atrial Fibrillation in Racial and Ethnic Minorities

BACKGROUND

Rhythm control strategies for atrial fibrillation (AF), including catheter ablation, are substantially underused in racial/ethnic minorities in North America.

OBJECTIVES

This study sought to describe outcomes in the CABANA trial as a function of race/ethnicity.

METHODS

CABANA randomized 2,204 symptomatic participants with AF to ablation or drug therapy including rate and/or rhythm control drugs. Only participants in North America were included in the present analysis, and participants were subgrouped as racial/ethnic minority or nonminority with the use of National Institutes of Health definitions. The primary endpoint was a composite of death, disabling stroke, serious bleeding, or cardiac arrest.

RESULTS

Of 1,280 participants enrolled in CABANA in North America, 127 (9.9%) were racial and ethnic minorities. Compared with nonminorities, racial and ethnic minorities were younger with median age 65.6 versus 68.5 years, respectively, and had more symptomatic heart failure (37.0% vs 22.0%), hypertension (92.1% vs 76.8%, respectively), and ejection fraction <40% (20.8% vs 7.1%). Racial/ethnic minorities treated with ablation had a 68% relative reduction in the primary endpoint (adjusted hazard ratio [aHR]: 0.32; 95% confidence interval [CI]: 0.13-0.78) and a 72% relative reduction in all-cause mortality (aHR: 0.28; 95% CI: 0.10-0.79). Primary event rates in racial/ethnic minority and nonminority participants were similar in the ablation arm (4-year Kaplan-Meier event rates 12.3% vs 9.9%); however, racial and ethnic minorities randomized to drug therapy had a much higher event rate than nonminority participants (27.4% vs. 9.4%).

CONCLUSION

Among racial or ethnic minorities enrolled in the North American CABANA cohort, catheter ablation significantly improved major clinical outcomes compared with drug therapy. These benefits, which were not seen in nonminority participants, appear to be due to worse outcomes with drug therapy. (Catheter Ablation vs Anti-arrhythmic Drug Therapy for Atrial Fibrillation Trial [CABANA]; NCT00911508).

Exercise Testing and Exercise Rehabilitation for Patients With Atrial Fibrillation

INTRODUCTION AND PURPOSE

Atrial fibrillation (AF) is a common cardiac arrhythmia associated with an increasing prevalence with advancing age. It is associated with dyspnea, exercise intolerance, and increased risk for clinical events, especially stroke and heart failure. This article provides a concise review of exercise testing and rehabilitation in patients with persistent or permanent AF.

CLINICAL CONSIDERATIONS

The first goal in the treatment of AF is to reduce symptoms (eg, palpitations) and a fast ventricular rate. The second goal is to reduce the risk of a stroke. Exercise testing and rehabilitation may be useful once these goals are achieved. However, there are no large, randomized exercise training trials involving patients with AF, and what data are available comes from single-site trials, secondary analyses, and observational studies.

EXERCISE TESTING AND TRAINING

There are no specific indications for performing a graded exercise test in patients with AF; however, such testing may be used to screen for myocardial ischemia or evaluate chronotropic response during exertion. Among patients with AF, exercise capacity is 15% to 20% lower and peak heart rate is higher than in patients in sinus rhythm. Exercise rehabilitation improves exercise capacity, likely improves quality of life, and may improve symptoms associated with AF. Whole-body aerobic exercise is recommended.

SUMMARY

Atrial fibrillation is a common cardiac condition and in these patients, exercise rehabilitation favorably improves exercise capacity. However, prospective randomized controlled trials are needed to better define the effects of exercise training on safety; quality of life; clinical outcomes; and central, autonomic, and peripheral adaptations.

CHA2DS2-VASc and SAMe-TT2R2 scores as predictors of recurrence for nonvalvular atrial fibrillation patients on vitamin K antagonists after radiofrequency catheter ablation

AIMS

Atrial fibrillation is the most common sustained arrhythmia in the general population, and circumferential pulmonary vein isolation has emerged as a cornerstone in the treatment of drug-resistant atrial fibrillation. However, there is a paucity of data regarding the CHA2DS2-VASc and SAMe-TT2R2 scores as predictors of outcomes among patients with nonvalvular atrial fibrillation on vitamin K antagonists after radiofrequency catheter ablation (RFCA).

METHODS

The current prospective observational study enrolled 304 consecutive patients with atrial fibrillation who underwent RFCA. Warfarin was maintained for at least 3 months after RFCA. The 1-year atrial fibrillation recurrence rate was documented.

RESULTS

Persistent atrial fibrillation (P = 0.003), heart failure (P < 0.001), an enlarged left atrium (P = 0.003), current smoking (P < 0.001), the CHA2DS2-VASc score (P = 0.001), and the SAMe-TT2R2 score (P < 0.001) were univariate associated with recurrent atrial fibrillation. Cutoff analysis showed that a CHA2DS2-VASc score at least 3 (areas under the curve = 0.612; 95% confidence interval 0.537-0.687) and a SAMe-TT2R2 score at least 5 (areas under the curve = 0.642, 95% confidence interval 0.575-0.708) had the highest predictive value for atrial fibrillation recurrence. Patients with a CHA2DS2-VASc score at least 3 (P < 0.001) and a SAMe-TT2R2 score at least 5 (P = 0.001) had a higher probability of experiencing atrial fibrillation recurrence after RFCA compared with patients with a CHA2DS2-VASc score less than 3 and a SAMe-TT2R2 score less than 5.

CONCLUSION

CHA2DS2-VASc and SAMe-TT2R2 scores were associated with 1-year recurrence of atrial fibrillation in patients on vitamin K antagonists after RFCA. For CHA2DS2-VASc and SAMe-TT2R2 scores, a cutoff value of at least 3 and at least 5 had the highest predictive value for atrial fibrillation recurrence, respectively.

Efficacy of Ablation Lesion Sets in Addition to Pulmonary Vein Isolation for Paroxysmal Atrial Fibrillation: Findings From the SMASH - AF Meta-Analysis Study Cohort

Background

The objective was to explore the efficacy of ablation lesion sets in addition to pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation. The optimal strategy for catheter ablation of paroxysmal atrial fibrillation is debated.

Methods and Results

The SMASH‐AF (Systematic Review and Meta‐analysis of Ablation Strategy Heterogeneity in Atrial Fibrillation) study cohort includes trials and observational studies identified in PubMed, Scopus, and Cochrane databases from January 1 1990, to August 1, 2016. We included studies reporting single procedure paroxysmal atrial fibrillation ablation success rates. Exclusion criteria included insufficient reporting of outcomes, ablation strategies that were not prespecified and uniform, and a sample size of fewer than 40 patients. We analyzed lesion sets performed in addition to PVI (PVI plus) using multivariable random‐effects meta‐regression to control for patient, study, and procedure characteristics. The analysis included 145 total studies with 23 263 patients (PVI‐only cohort: 115 studies, 148 treatment arms, 16 500 patients; PVI plus cohort: 39 studies; 46 treatment arms, 6763 patients). PVI plus studies, as compared with PVI‐only studies, included younger patients (56.7 years versus 58.8 years, P=0.001), fewer women (27.2% versus 32.0% women, P=0.002), and were more methodologically rigorous with longer follow‐up (29.5 versus 17.1 months, P 0.004) and more randomization (19.4% versus 11.8%, P<0.001). In multivariable meta‐regression, PVI plus studies were associated with improved success (7.6% absolute improvement [95% CI, 2.6–12.5%]; P<0.01, I²=88%), specifically superior vena cava isolation (4 studies, 4 treatment arms, 1392 patients; 15.1% absolute improvement [95% CI, 2.3–27.9%]; P 0.02, I²=87%). However, residual heterogeneity was large.

Conclusions

Across the paroxysmal atrial fibrillation ablation literature, PVI plus ablation strategies were associated with incremental improvements in success rate. However, large residual heterogeneity complicates evidence synthesis.

Which patients with atrial fibrillation undergo an ablation procedure today in Europe? A report from the ESC-EHRA-EORP Atrial Fibrillation Ablation Long-Term and Atrial Fibrillation General Pilot Registries

Aims

Rhythm control management in patients with atrial fibrillation (AF) may be unequal across Europe. The aim of this study was to investigate how selective the patient cohort referred for AF ablation is, as compared to the general AF population in Europe, and to describe the governing mechanisms for such selection.

Methods and results

Descriptive comparative statistical analyses of the baseline characteristics were performed between the cohorts of Atrial Fibrillation Ablation Long-Term (ESC EORP AFA-LT) registry, designed to provide a picture of contemporary real-world AF ablation, and the AF population from the AF-General (ESC EORP AF-Gen) pilot registry. Data collection was performed using a web-based system. In the AFA and in the Atrial Fibrillation General (AFG) pilot registries, 3593 and 3049 patients were enrolled, respectively. Patients who underwent AF ablation were younger, more commonly male, and had significantly less comorbidities. Atrial Fibrillation Ablation patients often presented without comorbidities, resulting in a lower risk of stroke (CHA2DS2-VASc ≥5: 2.9% vs. 24.5%, all P &lt; 0.001) and bleeding (HAS-BLED ≥2: 8.5% vs. 40.5%, P &lt; 0.001) but with European Heart Rhythm Association (EHRA) scores &gt;1 and more prevalent AF-related symptoms such as palpitations, fatigue, and weakness (all P &lt; 0.001) as compared to the general AF patients. Atrial Fibrillation Ablation patients were significantly more often male, had higher left ventricular ejection fraction (59.5% vs. 52.4%) and smaller left atrial size on echocardiogram (P &lt; 0.001 each).

Conclusion

The comparison of the patient cohorts in the AFA and AFG registries showed that AF ablation in European clinical practice is mostly performed in relatively young, symptomatic and relatively healthy patients.

U-Shaped Relationship Between Left Atrium Size on Echocardiography and 1-Year Recurrence of Atrial Fibrillation After Radiofrequency Catheter Ablation - Prognostic Value Study

BACKGROUND

The larger the left atrium anteroposterior dimension (LAD) and left atrium volume (LAV), the stronger the association with recurrent atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA). Patients with a smaller left atrium (LA) size, however, also have increased AF recurrence.

METHODS AND RESULTS

In 521 patients, routine 48-h Holter electrocardiogram and echocardiography were obtained at each outpatient visit every 3 months for 12 months. On multivariate analysis, AF type, LAD, and LAV calculated using the ellipsoid model/body surface area (LAVe/BSA) were independent predictors of AF recurrence. Patients were divided into 7 groups at 0.4-cm increments of LAD: ≤3 cm, LAD≤3 cm, 3.05.0 cm. Compared with the 3.4-3.8-cm group, the adjusted HR were 3.88 (95% CI: 2.02-7.46, P<0.001), 1.03 (95% CI: 0.50-2.12, P=0.939), 0.96 (95% CI: 0.52-1.77, P=0.901), 1.36 (95% CI: 0.72-2.57, P=0.347), 3.04 (95% CI: 1.67-5.53, P<0.001), and 4.07 (95% CI: 1.93-8.60, P<0.001), respectively. Similarly, we divided LAVe/BSA into 8 groups and also observed a U-shaped curve for AF recurrence.

CONCLUSIONS

Both larger and smaller LAD and LAVe/BSA were associated with a higher risk of AF recurrence 1 year after RFCA. The association of LA size and AF recurrence after RFCA is represented by a U-shaped curve.

Secular trends in success rate of catheter ablation for atrial fibrillation: The SMASH-AF cohort

BACKGROUND

Approaches, tools, and technologies for atrial fibrillation (AF) ablation have evolved significantly since its inception. We sought to characterize secular trends in AF ablation success rates.

METHODS

We performed a systematic review and meta-analysis of AF ablation from January 1, 1990, to August 1, 2016, searching PubMed, Scopus, and Cochrane databases. Major exclusion criteria were insufficient outcome reporting and ablation strategies that were not prespecified and uniform. We stratified treatment arms by AF type (paroxysmal AF; nonparoxysmal AF) and analyzed single-procedure outcomes. Multivariate meta-regressions analyzed effects of study, patient, and procedure characteristics on success rate trends. Registered in PROSPERO (CRD42016036549).

RESULTS

A total of 180 trials and observational studies with 28,118 patients met inclusion. For paroxysmal AF ablation studies, unadjusted success rate summary estimates ranged from 73.1% in 2003 to 77.1% in 2016, increasing by 0.9%/year (95% CI 0.4%-1.4%; P = .001; I² = 90%). After controlling for study design and patient demographics, rate of improvement in success rate summary estimate increased (1.6%/year; 95% CI 0.9%-2.2%; P = .001; I² = 87%). For nonparoxysmal AF ablation studies, unadjusted success rate summary estimates ranged from 70.0% in 2010 to 64.3% in 2016 (1.1%/year; 95% CI -1.3% to 3.5%; P = .37; I² = 85%), with no improvement in multivariate analyses.

CONCLUSIONS

Despite substantial research investment and health care expenditure, improvements in AF ablation success rates have been incremental. Meaningful improvements may require major paradigm or technology changes, and evaluation of clinical outcomes such as mortality and quality of life may prove to be important going forward.