Data at Heart Rhythm 2026 highlight key Boston Scientific therapies

Rhea-AI Summary

Boston Scientific (NYSE: BSX) presented multiple late-breaking clinical results at Heart Rhythm 2026 highlighting FARAPULSE PFA and WATCHMAN LAAC technologies. Key outcomes: AVANT GUARD showed PFA superiority over anti-arrhythmic drugs (56.0% vs 30.1% primary effectiveness at 12 months); PFA safety MAE 5.1%. Feasibility and real-world cohorts reported high PVI durability (up to 96.4%) and procedural success for combined PFA+WATCHMAN procedures.

Long-term and subgroup data showed WATCHMAN reduced non-procedural bleeding versus NOACs and lower stroke rates versus control in ASAP-TOO, though some studies had enrollment or sample-size limits.

Positive

• AVANT GUARD: primary effectiveness 56.0% vs 30.1% (PFA vs AAD)
• AVANT GUARD: major adverse event rate 5.1% at 12 months
• FARAFLEX optimized PVI durability increased to 96.4% per vein
• ALIGN-AF: 100% acute ablation success (n=122)
• WATCHMAN FLX Pro: 100% procedural success and 90.6% complete closure

Negative

• ASAP-TOO ended early for slow enrollment, limiting interpretation
• CHAMPION-AF no-prior-ablation subgroup showed efficacy 7.5% (device) vs 5.7% (NOAC)
• Several datasets are small or feasibility-phase (e.g., n=13, n=34, n=122)

Market Context

This announcement highlights robust clinical performance across key Boston Scientific cardiovascular...

Analysis

This announcement highlights robust clinical performance across key Boston Scientific cardiovascular platforms, including FARAPULSE PFA, WATCHMAN LAAC devices and the EMBLEM MRI S-ICD. The data span pivotal, feasibility, real‑world and long‑term studies, with multiple safety and effectiveness endpoints met. In recent months, the company also reported strong Q1 2026 financial results and advanced its cardiovascular portfolio. Investors may track how these outcomes support adoption trends and interact with ongoing strategic moves, such as acquisitions and product clearances.

Key Figures

Primary effectiveness (PFA): 56.0% at 12 months Primary effectiveness (AADs): 30.1% at 12 months Major adverse events: 5.1% at 12 months +5 more

8 metrics

Primary effectiveness (PFA) 56.0% at 12 months AVANT GUARD trial vs anti-arrhythmic drugs

Primary effectiveness (AADs) 30.1% at 12 months AVANT GUARD trial comparator arm

Major adverse events 5.1% at 12 months AVANT GUARD primary safety endpoint

PVI durability (optimized) 96.4% per-vein ELEVATE-PF optimized group (n=34)

Concomitant PFA acute success 100% (122/122) ALIGN-AF sub-study FARAWAVE ablation

WATCHMAN FLX Pro closure 90.6% (96/106) Complete LAA closure at mean 66 days

Non-procedural bleeding (prior ablation) 9.0% vs 17.0% CHAMPION-AF sub-analysis WATCHMAN FLX vs NOACs

Stroke/systemic embolism (ASAP-TOO) 7.8% vs 11.4% LAAC devices vs control over five years

Historical Context

5 past events · Latest: Apr 22 (Positive)

Pattern 5 events

Date	Event	Sentiment	24h Move	Catalyst
Apr 22	Q1 2026 earnings	Positive	+9.1%	Reported strong Q1 sales and EPS growth with broad segment strength.
Mar 30	Earnings call notice	Neutral	-9.0%	Announced timing and access details for Q1 2026 results webcast.
Mar 30	Device FDA clearance	Positive	-9.0%	Received FDA 510(k) clearance for Asurys Fluid Management System.
Mar 06	ACC investor event	Neutral	-2.3%	Planned investor event around key cardiology clinical data at ACC.
Feb 25	Acquisition target earnings	Neutral	-2.2%	Penumbra Q4/FY results amid its proposed acquisition by Boston Scientific.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Pattern Detected

Recent history shows strong clinical and earnings news sometimes coinciding with both gains and declines, indicating inconsistent near-term price responses to positive catalysts.

Recent Company History

Over the past six months, Boston Scientific reported strong Q1 2026 results with net sales of $5.203 billion and adjusted EPS of $0.80, which saw a 9.09% gain the next day. Other corporate and clinical updates, including an FDA 510(k) clearance for the Asurys Fluid Management System and multiple conference and investor events, coincided with declines between 2–9%. Today’s positive Heart Rhythm 2026 data on FARAPULSE, WATCHMAN, and EMBLEM arrives after this mixed pattern of market reactions to favorable news.

Key Terms

pulsed field ablation, left atrial appendage closure, non-vitamin K antagonist oral anticoagulants, systemic embolism, +3 more

7 terms

pulsed field ablation medical

"Positive data for FARAPULSE™ Pulsed Field Ablation and WATCHMAN™ LAAC Devices"

Pulsed field ablation is a heart procedure that uses very short, high-voltage electrical pulses to selectively disrupt abnormal heart tissue that causes irregular rhythms, rather than heating or freezing it. For investors, it matters because this approach can shorten procedure times, reduce damage to nearby structures, and potentially lower complication rates compared with traditional thermal methods, which can affect device adoption, hospital costs, and market demand for treatment tools.

left atrial appendage closure medical

"WATCHMAN™ Left Atrial Appendage Closure (LAAC) technologies."

A medical procedure that seals off the left atrial appendage, a small pouch in the heart where blood can pool and form clots in people with irregular heartbeats; sealing it is like plugging a gutter so debris can’t collect and cause a downstream flood. It matters to investors because devices, hospitals, and insurers involved in the procedure create revenue streams and regulatory or adoption changes can affect sales, costs and long‑term market size for related medical technology.

non-vitamin K antagonist oral anticoagulants medical

"LAAC therapy with the WATCHMAN FLX implant compared to non-vitamin K antagonist oral anticoagulants"

Oral medications that prevent blood clots by blocking specific steps in the clotting process instead of interfering with vitamin K. Think of them as placing a targeted roadblock at a particular junction of clot formation rather than shutting down the whole highway; they are used to reduce stroke and clot risk in people with irregular heartbeats or prior clots. Investors track them because prescribing trends, safety records, patent status and approvals directly affect drug sales, market share and long‑term revenue potential.

systemic embolism medical

"risk of ischemic stroke or systemic embolism in patients with NVAF"

A systemic embolism happens when a blood clot or other debris breaks loose, travels through the bloodstream and lodges in an artery supplying an organ (such as the brain, kidney or limb), blocking blood flow and causing sudden organ damage. Investors care because the frequency and severity of these events affect demand for treatments and devices, shape clinical trial results and regulatory decisions, and influence healthcare costs, liability and insurer reimbursement risks.

ischemic stroke medical

"reducing the risk of ischemic stroke or systemic embolism in patients with NVAF"

An ischemic stroke occurs when a blood vessel supplying the brain is blocked, cutting off oxygen and nutrients to part of the brain — like a kinked garden hose that stops water flow. It matters to investors because its incidence and outcomes drive demand for drugs, emergency devices, diagnostic tools, rehabilitation services and clinical trials; changes in treatment effectiveness, approvals or costs can materially affect healthcare companies and insurers.

subcutaneous implantable defibrillator medical

"EMBLEM™ MRI Subcutaneous Implantable Defibrillator (S-ICD) were also presented"

A subcutaneous implantable defibrillator is a small medical device placed under the skin near the chest that detects dangerously fast heart rhythms and delivers a controlled shock to restore a normal heartbeat, without wires threaded into the heart. Investors care because its safety profile, regulatory approvals, reimbursement rules and adoption rates directly affect sales, replacement and follow-up costs, and the competitive landscape in cardiac device markets—think of it as an external alarm and reset button implanted under the skin.

non-valvular atrial fibrillation medical

"patients with or without prior ablation for non-valvular atrial fibrillation (NVAF)."

An irregular, often rapid heartbeat originating in the heart’s upper chambers (atria) that is not caused by a mechanical heart valve or significant narrowing of the mitral valve. It matters because this specific label changes which drugs and devices are considered safe and approved, and therefore the size of the eligible patient market and rejection or acceptance by regulators; untreated, it raises stroke and hospitalization risk, so treatment choice influences sales and liability.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Positive data for FARAPULSE™ Pulsed Field Ablation and WATCHMAN™ LAAC Devices underscore therapy safety and effectiveness in late-breaking clinical trial sessions 

MARLBOROUGH, Mass. and CHICAGO, April 26, 2026 /PRNewswire/ -- Boston Scientific Corporation (NYSE: BSX) today announced data supporting use of the company's FARAPULSE™ Pulsed Field Ablation (PFA) Platform and WATCHMAN™ Left Atrial Appendage Closure (LAAC) technologies. All data were presented at Heart Rhythm 2026, the annual meeting of the Heart Rhythm Society, held in Chicago from April 24-26.

Results from the AVANT GUARD clinical trial of FARAPULSE™ PFA
The randomized AVANT GUARD clinical trial met all safety and effectiveness endpoints and demonstrated statistical superiority of PFA over anti-arrhythmic drugs (AADs) with significantly higher primary effectiveness. The trial is the first randomized pivotal study to evaluate patients with persistent atrial fibrillation (AF) who had not previously been treated for their condition – a historically understudied, high-risk population. Patients were randomized or assigned to receive pulmonary vein isolation (PVI) and left atrial posterior wall isolation (PWI) using the FARAWAVE™ PFA Catheter or given AADs for treatment. Results were simultaneously published in The New England Journal of Medicine.

Key findings from the trial:

• PFA achieved superiority over AADs with a primary effectiveness rate of 56.0% at 12 months compared to 30.1% in the AAD group.
• The primary safety endpoint was met with major adverse event rate of 5.1% at 12 months.
• Significantly more patients in the PFA group (51.7%) were free from atrial arrhythmia recurrence at 12 months, compared to 32.2% in the AAD group.

Results from the feasibility study of the FARAFLEX™ PFA Catheter
The single-arm, ELEVATE-PF feasibility trial is examining the safety and effectiveness of the FARAFLEX PFA Catheter, a novel, high-density large focal map-and-ablate catheter designed to treat complex arrhythmias, in patients with paroxysmal and persistent AF. The trial enables ongoing PFA dosing and workflow refinements based on a study design incorporating prospective high-density remapping, analyzing patients sequentially in three groups – feasibility, improved and optimized.

Key findings from this ongoing trial:

• With workflow improvements, PVI durability – the permanence of an ablation lesion over time – increased from 80.4% on a per-vein basis in the feasibility group (n=13) to 96.4% in the optimized group (n=34).
• Within the optimized group, PVI durability in patients with persistent AF was 95.6% at two months (n=17).
• There were no reports of stroke, pulmonary vein stenosis, hemolysis or coronary spasm.

Clinical outcomes associated with real-world concomitant PFA and LAAC interventions
Prospective, interim, real-world evidence from ALIGN-AF, a multi-center sub-study of the DISRUPT-AF registry, reinforced that concomitant procedures combining the FARAWAVE PFA Catheter and the WATCHMAN FLX™ Pro LAAC Device could be performed safely without compromising acute procedural success. The study, which includes 122 patients at 12 sites with 24 physicians performing the procedures, assessed peri-device leaks between 45 and 90 days following implant and will assess arrhythmia recurrence at six and 12 months.

Key findings from available data at three months:

• Ablation with the FARAWAVE PFA Catheter achieved a 100% (n=122/122) acute success rate. Ablation parameters such as lesion sets and procedure duration were consistent with those observed in standalone PFA procedures.
• LAAC with the WATCHMAN FLX Pro implant also achieved 100% (n=119/119) procedural success and 90.6% (n=96/106) complete LAA closure at a mean of 66 days with no clinically relevant leaks or device-related thrombus reported.

Sub-analysis of the CHAMPION-AF clinical trial in patients with or without prior ablation
A sub-analysis of the CHAMPION-AF trial studied LAAC therapy with the WATCHMAN FLX implant compared to non-vitamin K antagonist oral anticoagulants (NOACs) in patients with and without prior ablation for non-valvular atrial fibrillation (NVAF). The analysis included 1,434 patients who had a cardiac ablation for AF prior to randomization and 1,565 patients who did not have a previous ablation. The results highlighted that for patients in both arms of the sub-analysis, the device provided statistically significant protection from non-procedural bleeding and had similar efficacy to NOACs.

Key findings from the sub-analysis:

• The WATCHMAN FLX device provided statistically significant protection from non-procedural bleeding, including major and clinically relevant non-major bleeding (CRNMB), compared to NOACs in patients who had a prior ablation (9.0% vs. 17.0%) and in patients with no prior ablation (12.8% vs. 20.8%).
  • CRNMB is defined within the trial as life-impacting non-major bleeds that require medical intervention, hospitalization or an increased level of care.

• The WATCHMAN FLX device had similar efficacy to NOACs for the occurrence of stroke, cardiovascular or unexplained death, or systemic embolism, regardless of whether they had a prior ablation (3.9% for both the device and NOACs in patients with prior ablation; 7.5% for the device group vs. 5.7% for the NOAC group in patients with no prior ablation).

Long-term outcomes after LAAC therapy in patients not eligible for anticoagulation
Five-year follow-up data from the ASAP-TOO trial provided evidence on the legacy WATCHMAN LAAC device (n=284) or the WATCHMAN FLX LAAC device (n=20) compared to a single antiplatelet (SAPT) medication or no medication in reducing the risk of ischemic stroke or systemic embolism in patients with NVAF who were deemed unsuitable for oral anticoagulation (OAC) medication. While the findings contribute new clinical data on LAAC and stroke protection, interpretation is limited as the trial ended early due to slow enrollment driven by physician preference for the device over SAPT/no medication, not safety-related factors, and variability in long-term follow-up.

Key findings from the trial:

• There was a lower rate of occurrence of stroke or systemic embolism with an LAAC device compared to the control group (7.8% vs. 11.4%).
  • LAAC therapy was associated with significantly fewer disabling strokes compared to the control group (1.1% vs. 3.8%).
• The device group had a rate of 1.0% for all-cause death, ischemic stroke, systemic embolism or device- or procedure-related events requiring open cardiac surgery or major endovascular intervention within discharge or seven days.

Results from the investigator-sponsored PRAETORIAN DFT study of the EMBLEM™ MRI Subcutaneous Implantable Defibrillator (S-ICD) were also presented as a late-breaking clinical trial, meeting the primary endpoint. Findings from the trial achieved non-inferiority in the likelihood of failed therapy when omitting defibrillation testing as guided by the PRAETORIAN score – an estimate of successful delivery of life-saving therapy – in patients receiving the device for the first time.¹

"The data presented at Heart Rhythm 2026 reflect the continued momentum of our cardiovascular portfolio and underscores our commitment to advancing innovation through comprehensive clinical evidence across the spectrum of cardiac care," said Kenneth Stein, M.D., senior vice president and global chief medical officer, Boston Scientific. "These findings support the potential expansion of our FARAPULSE PFA Platform into more complex patient populations, highlight the value of a combined therapeutic approach with our WATCHMAN FLX Pro LAAC Device, may enhance the implant experience with the EMBLEM MRI S-ICD and position us to deliver a broader portfolio of differentiated solutions for physicians treating patients with cardiovascular diseases."

About Boston Scientific
Boston Scientific transforms lives through innovative medical technologies that improve the health of patients around the world. As a global medical technology leader for more than 45 years, we advance science for life by providing a broad range of high-performance solutions that address unmet patient needs and reduce the cost of healthcare. Our portfolio of devices and therapies helps physicians diagnose and treat complex cardiovascular, respiratory, digestive, oncological, neurological and urological diseases and conditions. Learn more at www.bostonscientific.com and follow us on LinkedIn.  

Cautionary Statement Regarding Forward-Looking Statements

This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934.  Forward-looking statements may be identified by words like "anticipate," "expect," "project," "believe," "plan," "estimate," "intend" and similar words. These forward-looking statements are based on our beliefs, assumptions and estimates using information available to us at the time and are not intended to be guarantees of future events or performance. These forward-looking statements include, among other things, statements regarding our business plans and product performance and impact, and clinical trials. If our underlying assumptions turn out to be incorrect, or if certain risks or uncertainties materialize, actual results could vary materially from the expectations and projections expressed or implied by our forward-looking statements. These factors, in some cases, have affected and in the future (together with other factors) could affect our ability to implement our business strategy and may cause actual results to differ materially from those contemplated by the statements expressed in this press release. As a result, readers are cautioned not to place undue reliance on any of our forward-looking statements. 

Factors that may cause such differences include, among other things:  economic conditions, including the impact of foreign currency fluctuations; future U.S. and global political, competitive, reimbursement and regulatory conditions, including changing trade and tariff policies; geopolitical events, conflicts and tensions; manufacturing, distribution and supply chain disruptions and cost increases; disruptions caused by cybersecurity events; disruptions caused by public health emergencies or extreme weather or other climate change-related events; labor shortages and increases in labor costs; variations in outcomes of ongoing and future clinical trials and market studies; new product introductions; expected procedural volumes; the closing and integration of acquisitions; demographic trends; intellectual property; litigation; financial market conditions; the execution and effect of our business strategy, including our cost-savings and growth initiatives; and future business decisions made by us and our competitors. All of these factors are difficult or impossible to predict accurately and many of them are beyond our control. For a further list and description of these and other important risks and uncertainties that may affect our future operations, see Part I, Item 1A – Risk Factors in our most recent Annual Report on Form 10-K filed with the Securities and Exchange Commission, which we may update in Part II, Item 1A – Risk Factors in Quarterly Reports on Form 10-Q we have filed or will file hereafter.  We disclaim any intention or obligation to publicly update or revise any forward-looking statements to reflect any change in our expectations or in events, conditions or circumstances on which those expectations may be based, or that may affect the likelihood that actual results will differ from those contained in the forward-looking statements, except as required by law. This cautionary statement is applicable to all forward-looking statements contained in this document.

CONTACTS:
Steve Bailey
Media Relations
+1 (651) 582-4343 (office)
Steve.Bailey@bsci.com

Lauren Tengler
Investor Relations
+1 (508) 683-4479
BSXInvestorRelations@bsci.com

1 The manufacturer recommended VF conversion testing during EMBLEM S-ICD implant, replacement, and concomitant device implants is being evaluated based on the PRAETORIAN DFT trial results and additional available data.

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SOURCE Boston Scientific Corporation

FAQ

What did Boston Scientific (BSX) report about AVANT GUARD PFA results at Heart Rhythm 2026?

AVANT GUARD showed PFA primary effectiveness of 56.0% versus 30.1% for anti-arrhythmic drugs at 12 months. According to the company, the trial met safety and effectiveness endpoints with a 5.1% major adverse event rate at 12 months.

How durable was pulmonary vein isolation with FARAFLEX PFA in the ELEVATE-PF trial?

PVI durability improved to 96.4% per vein in the optimized FARAFLEX group. According to the company, durability rose from 80.4% in the feasibility cohort to 96.4% after workflow and dosing refinements.

What were the real-world outcomes for concomitant FARAWAVE PFA and WATCHMAN FLX Pro procedures (BSX)?

Real-world ALIGN-AF data reported 100% acute ablation success and 100% WATCHMAN procedural success. According to the company, 90.6% achieved complete LAA closure at a mean 66 days with no device-related thrombus reported.

Did WATCHMAN FLX reduce bleeding versus NOACs in CHAMPION-AF sub-analysis presented by Boston Scientific (BSX)?

Yes. According to the company, WATCHMAN FLX reduced non-procedural bleeding versus NOACs: 9.0% vs 17.0% in patients with prior ablation, and 12.8% vs 20.8% in patients without prior ablation.

What are limitations investors should note about the Heart Rhythm 2026 data from Boston Scientific (BSX)?

Several studies were small, feasibility, or ended early, which limits generalizability of findings. According to the company, ASAP-TOO closed early for slow enrollment and some cohorts had modest sample sizes.