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DATE

Thursday, May 7, 2026 at 4:30 p.m. ET

CALL PARTICIPANTS

  • Co-Chairman — Paul LaViolette
  • Chief Financial Officer — Jon Skinner
  • Co-Chairman of the Board — Bob Duggan
  • Chief Operating Officer — Liane Teplitsky

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TAKEAWAYS

  • Total Revenue -- $401,000 for the quarter, consisting of nPulse Catheter and Vybrance disposable sales.
  • Cost of Product Revenue -- $370,000, providing direct product margin context.
  • GAAP Costs and Expenses -- $19.6 million, up $1.6 million, driven by increased investment in clinical programs, partially offset by lower stock-based compensation.
  • Non-GAAP Costs and Expenses -- $17.4 million, up $4.7 million, reflecting higher trial and development activity compared to the prior year.
  • GAAP Net Loss -- $18.6 million, compared to $16.8 million in the prior year period.
  • Non-GAAP Net Loss -- $16.4 million, compared to $11.4 million in the prior year period.
  • Cash and Cash Equivalents -- $68.3 million as of March 31, 2026, down from $80.7 million at year end 2025.
  • Cash Used in Operating Activities -- $14.6 million, compared to $13.5 million in the prior year period and $14.8 million in Q4 2025.
  • Total European Feasibility Study Enrollment -- 177 patients for the nPulse Cardiac Catheter System, with 6-month follow-up for 95 subjects and 12-month follow-up for 53 subjects in the 5-second ablation cohort.
  • Key Clinical Efficacy Results -- 100% procedure success at 6 months (95/95), 96% at 12 months, and 90% Kaplan-Meier estimated freedom from recurrent AF at 12 months, sustained without antiarrhythmic drugs.
  • Primary Safety Endpoint -- 1.7% serious adverse event rate across 177 treated subjects.
  • U.S. IDE Pivotal Trial Enrollment -- NANOPULSE-AF study began in April with first 7 patients treated at a single site in one day; protocol allows up to 30 sites and 215 patients, with no site allowed to enroll more than approximately 20 patients.
  • Pivotal Study Enrollment Timeline -- Company now anticipates enrollment completion in early Q4 2026, ahead of prior year-end guidance.
  • Cardiac Clamp Feasibility Study -- Over 60 patients treated in Europe across 6 clinical sites, with 34 patients mapped at 3 months showing a 94% PVI success rate; mean ablation time per patient was 41 seconds.
  • Vybrance System Revenue -- approximately $400,000 recognized in the quarter, with ongoing disciplined market development.
  • PRECISE-BTN Study Enrollment -- First 50-patient milestone reached; study expanding to 100 patients for benign thyroid nodule ablation.
  • Clinical Data – Benign Thyroid Nodules -- Results from 15-22 months post-treatment show 74% volume reduction and no regrowth, as presented at NASIT.
  • Shelf Registration and ATM Facility -- $200 million shelf registration fully available and approximately $60 million ATM program in effect as of March 31, 2026; Board approval obtained for insider participation.
  • Leadership Changes -- Appointment of Dr. David Kenigsberg as Chief Medical Officer and Liane Teplitsky as Chief Operating Officer to support accelerated clinical and regulatory execution.

SUMMARY

Pulse Biosciences (PLSE 2.60%) reported that landmark clinical data from a 177-patient European feasibility study delivered 100% procedural success at 6 months and 96% at 12 months for the nPulse Cardiac Catheter System, with a low 1.7% serious adverse event rate. The company began enrollment in its U.S. IDE pivotal trial, NANOPULSE-AF, and advanced its regulatory and commercial timelines by prioritizing the cardiac catheter program and strengthening the executive team. Cash and equivalents closed at $68.3 million, while operating expenses rose in line with increased clinical activity, and liquidity was bolstered by a $200 million shelf registration and a $60 million ATM program.

  • Enrollment in the pivotal IDE study is progressing rapidly, with site activations accelerating and completion now forecast in early Q4 2026.
  • The cardiac clamp program showed sustained high procedural efficiency and reproducibility across expanding clinical sites in Europe, maintaining a consistent 94% PVI success rate.
  • Updated clinical data from the Vybrance system demonstrated durable nodule reduction and high patient satisfaction, supporting further expansion of the PRECISE-BTN study and regulatory submissions.
  • Pulse Biosciences continues to pursue strategic partnerships with global electrophysiology mapping system providers, facilitated by broad device compatibility.
  • Company management emphasized disciplined expense growth, stating, "Expense growth remains deliberate and focused on long-term value creation."

INDUSTRY GLOSSARY

  • nsPFA (Nanosecond Pulsed Field Ablation): A nonthermal ablation therapy delivering ultra-short electrical pulses for targeted cell death with preservation of adjacent tissue.
  • PVI (Pulmonary Vein Isolation): A procedure that electrically isolates the pulmonary veins from the left atrium to treat atrial fibrillation.
  • IDE (Investigational Device Exemption): FDA authorization for the clinical study of a new medical device before market approval.
  • Kaplan-Meier Estimate: A statistical method used to estimate the survival function and freedom from events, such as arrhythmia recurrence, over time.
  • ATM Program (At-the-Market Program): A public offering allowing a listed company to sell shares incrementally into the open market at prevailing prices.
  • CE Mark: A regulatory certification indicating conformity with health, safety, and environmental protection standards for products sold within the European Economic Area.
  • ASCs (Ambulatory Surgery Centers): Outpatient facilities where surgeries and procedures are performed without hospital admission.

Full Conference Call Transcript

Paul LaViolette: Good afternoon, and thank you for joining us. For those of you that are new to the Pulse Biosciences story, let me start with a brief overview of the technology at the core of everything we do. Pulse Biosciences is the pioneer of Nanosecond Pulsed Field Ablation, or nsPFA, a fundamentally new category of energy that we believe will change the way soft tissues in the human body are treated across multiple disease states. Conventional ablation modalities, whether radio frequency, cryoablation, microwave or even today's first-generation microsecond pulsed field systems share common limitations. They rely on relatively long-duration energy delivery windows. They deliver current or temperature changes through tissue inefficiently.

They cover small treatment areas, create shallow lesions and often require repeated applications. Our nsPFA platform creates an entirely different and proprietary approach and experience. We deliver pulses measured in billionths of a second. At that time scale, with each pulse, the duration of a few billionths of a second, the energy interacts with cells through a nonthermal mechanism that initiates regulated cell death in target tissue while leaving collagen, blood vessels, nerves and other noncellular structures intact. The practical effect of nsPFA delivery is meaningful. nsPFA creates deeper and more durable lesions delivered in dramatically less time while providing a margin of safety that has been a core challenge for legacy energy sources.

Surrounding this core technology, we have built a substantial and growing intellectual property state that positions Pulse Biosciences as the clear first mover and the long-term leader in nanosecond PFA. We are developing this platform to treat atrial fibrillation, where the unmet need is enormous and where our differentiation seems to be pronounced. And we are advancing additional applications that leverage these remarkable underlying therapeutic advantages of nsPFA energy. Against this backdrop, the first quarter of 2026 produced a true inflection point for Pulse. Three milestones defined the quarter and recent progress produced by our team.

First, we presented landmark late-breaking data from our large European feasibility study at the AF Symposium, which set a new bar for what physicians and patients should expect from a pulsed field ablation therapy. Second, leveraging this unprecedented clinical data set, we made the decision to strategically reshape Pulse Biosciences to focus on our highest value opportunity, our nPulse Cardiac Catheter for atrial fibrillation and have rapidly reorganized our focus and operations to allocate an increased portion of our overall company resources to this program. And third, in just the past several weeks, we commenced enrollment in our IDE U.S. pivotal study, NANOPULSE-AF, treating our first patients with the nsPFA catheter system in early April.

We also released updated follow-up data from the European feasibility study, further validating strong positive outcomes. Each one of these milestones represents a meaningful achievement. Together, they reflect a clinical development program of great importance moving at impressive speed. Today, I will provide updates on our nsPFA system in more detail, and we'll then turn the call over to our Chief Financial Officer, Jon Skinner, to review the first quarter financial results. We will then conclude with a question-and-answer session joined by Bob Duggan, Co-Chair of the Board; and Liane Teplitsky, Chief Operating Officer. I will now begin with our nPulse Cardiac Catheter System for AF ablation.

Our nPulse Cardiac Catheter System is purpose-built to address atrial fibrillation with a 360-degree circular design. The clinical goal of ablation in the treatment of paroxysmal AF is straightforward, electrically isolate the pulmonary veins from the left atrium to prevent abnormal electrical signals from triggering arrhythmias. Achieving that goal durably, efficiently and safely has been the ongoing challenge in the field. And the ability to advance improvements in AF care will set our catheter apart from existing technology in this rapidly growing market. The nPulse nsPFA system represents what we believe is the world's first true single-shot pulmonary vein ablation treatment platform for AF.

Early data suggests a physician can now rapidly position the circular catheter, deliver a single 5-second application of nanosecond pulse energy per target location and achieve a complete circumferential and transmural ablation without repositioning, without rotating and without the need to stack multiple overlapping lesions. That workflow advantage stems directly from the underlying ultrashort duration and high energy pulse parameters unique to nsPFA energy and Pulse's unique catheter design, which is possible in part because of the unique properties of the energy. Because the energy is delivered in billionth of a second, the total cumulative energy transferred to tissue is dramatically lower, which means no measurable temperature rise and minimal neuromuscular stimulation.

The result is a system designed for speed, reproducibility and durability, qualities that make the procedure more streamlined and efficient for operators as we redefine the standard of care in electrophysiology. Since our last call, we announced a meaningful strategic alignment to prioritize and accelerate the development and future commercialization of our nPulse cardiac catheter ablation system. The European feasibility study results from 177 patients send a powerful message. The nPulse Cardiac Catheter System has the potential to improve clinical practice for millions of patients living with atrial fibrillation. In response, we are increasingly prioritizing the program by allocating additional resources to our clinical and R&D teams to accelerate time to market for this catheter system.

This investment in resources and focus will accelerate the pivotal IDE study, the introduction of additional clinical studies and the development of our next-generation catheters. As part of the strategic realignment, we continue to expand our EP leadership team. Most notably, Dr. David Kenigsberg has transitioned to a full-time Chief Medical Officer. Dr. Kenigsberg will lead our clinical strategy, investigator engagement, medical affairs and study execution as we enroll the pivotal IDE study and expand our clinical data set. In addition, we welcomed Liane Teplitsky to the Pulse Biosciences executive team as Chief Operating Officer, a newly created role on our executive leadership team.

Liane is a seasoned med tech executive with 20 years of experience and an exceptional track record of building and scaling innovative med tech businesses, particularly in electrophysiology. She held senior marketing and commercial leadership roles at Abbott Laboratories and St. Jude Medical, contributing to the development, clinical validation and global commercialization of electrophysiology therapies. She will oversee our clinical, regulatory, quality and commercial functions and will be focused on accelerating our strategic priorities with emphasis on the cardiac catheter development program. Collectively, the additions of David and Liane strengthen our ability to execute a successful pivotal IDE study and advance toward regulatory approvals. On the clinical data front, we had a landmark quarter.

At the Heart Rhythm 2026 meeting or HRS, Dr. Vivek Reddy, the national principal investigator of our pivotal study, presented late-breaking updated data from our nPulse Cardiac Catheter System first-in-human feasibility study. Building upon the very positive data presented at the AF Symposium in February, this newly expanded data set included 6-month follow-up on 95 subjects and 12-month follow-up on 53 subjects within the 5-second ablation cohort. The results were simply outstanding and reinforce the differentiated clinical profile we have observed since the earliest cases. Key findings included sustained 100% procedure success by 24-hour Holter of evaluable patients at 6 months with 95 of 95 patients meeting the endpoint.

Sustained 96% procedural success by 24-hour Holter of evaluable patients at 1 year and sustained 90% Kaplan-Meier estimated freedom from recurrent AF, atrial flutter or atrial tachycardia also at 1 year. Procedural performance data at HRS improved from the already impressive readout at AS Symposium with lower atrial dwell time, lower average number of applications and lower procedure and fluoroscopy times. The safety profile also remained excellent with a primary safety endpoint, serious adverse event rate of just 1.7% across 177 treated subjects. These outcomes are remarkable in a field where reported 20% to 25% AF recurrence rates are typical.

It is particularly notable that our results were achieved without antiarrhythmic drugs and with a high degree of consistency across operators and sites, which is typically difficult to achieve at an early stage of clinical development. As Dr. Reddy noted, the durability of pulmonary vein isolation plus the procedural efficiency we are observing is a positive combination not typically expected at this point in the clinical program. These results reflect the underlying advantages of nanosecond PFA and our innovative catheter design, deeper lesion formation with fewer applications, lower cumulative energy and durable pulmonary vein isolation in a fast reproducible workflow.

We believe our system directly addresses the limitations of current generation microsecond ablation catheters by enabling complete durable isolation in a single energy delivery with the potential to reduce procedure time significantly. This time-saving advantage represents a meaningful potential capacity expansion for EP procedures and would likely drive rapid adoption of nsPFA as the preferred next-generation energy in the market, especially in light of the potential benefits of the efficacy improvements observed to date.

As we look ahead toward the migration of AF ablation procedures to ambulatory surgery centers or the ASCs, we expect all the benefits of the nPulse cardiac catheter to align directly with the needs of the ASC and the overall expansion of treating the growing population of patients with atrial fibrillation. The compelling body of clinical evidence from our European feasibility study provided a strong foundation for the most important operational milestone of the quarter, the commencement of our U.S. IDE pivotal trial.

In early April, we announced that the first patients had been enrolled in our NANOPULSE-AF study, a prospective multicenter IDE pivotal clinical investigation evaluating the nPulse Cardiac Catheter System for the treatment of recurrent drug-resistant symptomatic paroxysmal atrial fibrillation. The first 7 patients were treated at St. Bernards Medical Center in Jonesboro, Arkansas in just 1 day under the leadership of Dr. Devi Nair, principal investigator of the Arrhythmia Research Group. Dr. Nair has not previously used the nPulse catheter. And the efficiency with which the procedures were completed speaks volumes about the short learning curve and usability benefits we can expect from our system.

Early feedback from physician investigators reinforces the user-friendly nature of the system and the efficient reproducible streamlined workflow it supports. This positive feedback has helped create significant enthusiasm for study participation. Site activation is accelerating, and we are encouraged by the current and planned enrollment momentum we are seeing. Based on the excitement and momentum coming out of HRS, along with the benefit of our strategic realignment, we are tightening our enrollment time line to reflect the likely faster pace of our study execution. We now anticipate enrollment to be completed in early Q4 2026 compared to prior guidance that planned enrollment completion by the end of 2026.

Regarding study follow-up, the final proportion of participants with primary effectiveness success or freedom from treatment failure through 12 months will be estimated using a Bayesian analysis that includes outcomes at 12 months for a subset of patients and at 6 months for the remainder. Using a blend of follow-up durations will shorten overall follow-up time for the study. This method allows determination of success earlier than traditional statistical methods used in other studies. Overall, we are accelerating both enrollment and follow-up time lines to optimize the planned filing date for the clinical PMA module.

On the regulatory front in Europe, we expect to use the data from our European feasibility study to finalize our CE submission in the second half of 2026 with the potential for CE Mark approval in mid-2027. We are also continuing discussions with potential strategic partner candidates. Potential partners include the world-class mapping providers and EP market leaders. A key advantage of the nPulse cardiac catheter is its ability to be integrated with all mapping systems. This creates a compelling synergy in which our partner or partners may gain access to the most advanced nanosecond PFA energy solution available. These partnership conversations are active, and we will share details of partnership prospects when the time is appropriate.

Let's now discuss our surgical ablation clamp. Our nPulse cardiac clamp pivotal study, NANOCLAMP-AF, is the first and only clinical study of a surgical device delivering PFA to receive FDA IDE approval. The nPulse cardiac clamp applies nanosecond PFA energy to create durable transmural lesion sets during concomitant procedures where the surgeon has direct cardiac tissue access and atrial fibrillation is present. The clinical opportunity is substantial. However, despite strong guideline support for concomitant AF treatment during cardiac surgery, adoption of currently available devices remains low.

We believe the primary adoption barriers have been procedural complexity, unreliable outcomes and too much time added to the surgery, concerns that nanosecond PFA may directly address through a combination of rapid energy delivery, reproducible lesion formation and a straightforward surgical workflow. We continue to believe that concomitant ablation for preoperative AF is significantly underutilized and that the speed and effectiveness of nsPFA energy can transform this therapy and market. Enrollment in NANOCLAMP-AF continued to progress during the first quarter. As a reminder, the trial is a prospective single-arm multicenter study designed to assess the primary safety and effectiveness of the nPulse cardiac surgical system in treating AF during concomitant cardiac surgeries.

We plan to enroll a target of 136 patients at approximately 20 sites, including 2 international locations. Reflecting our strategic prioritization of the EP catheter ablation program, including some resource shifts, we now expect to complete enrollment of this IDE study by the end of the first half of 2027. We have moderated near-term development in cardiac surgery while maintaining trial execution and regulatory preparation and clinical site activations continue to expand during Q1. In Europe, we continue to generate excellent results in our cardiac surgery feasibility study. To date, investigators have treated over 60 patients, and we have expanded the study to now include 6 clinical sites.

Within this 60-patient cohort, 34 patients underwent electroanatomical mapping approximately 3 months after their ablation procedures to assess the effectiveness and durability of the treatment. These data were presented at the European Heart Rhythm Association 2026 meeting and are very promising, with individual ablation times averaging a very rapid 41 seconds total per patient. Notably, as patient numbers have increased, the PVI success rate of 94% at approximately 3 months has remained consistent with the clinical outcomes we reported in our initial data readout in October of 2025. Surgeons using the system have reported favorable procedural characteristics, rapid ablation delivery, consistent lesion quality and smooth integration into existing surgical workflows without meaningful time or complexity added to the underlying surgery.

Feedback from the surgical community emphasizes that workflow efficiency and predictability matter as much as efficacy in the operating room. And the early signal is that nanosecond PFA delivers very favorably on both. We remain on track to submit for CE Mark by the end of 2026 using the European clinical data set. Turning to our nPulse Vybrance Percutaneous Electrode System. The nPulse Vybrance System applies nanosecond PFA technology to ablate soft tissue in surgical procedures through a percutaneous approach, offering, for example, an alternative to surgical removal for patients with symptomatic benign thyroid nodules.

Vybrance is designed to address this patient population through a minimally invasive outpatient procedure that reduces nodule volume, alleviate symptoms and preserve surrounding anatomy and normal thyroid function, outcomes that cannot be achieved with traditional surgical excision. In the first quarter, the team generated approximately $400,000 in revenue from nPulse Vybrance Systems and electrodes. Our approach continues to be extremely disciplined and remains focused on core market development objectives. We continue to operate at an intentionally limited scale to demonstrate how meaningful over the long term and how well we can service initial Vybrance customers in exploring along with them the potential of the nPulse Vybrance System.

Our work is focused on ensuring we generate robust clinical data to support a treatment indication while formalizing patient reimbursement to expand patient access in partnership with key accounts at large hospital systems in select geographies. On the clinical front, the PRECISE-BTN or Benign Thyroid Nodule study reached an important milestone with enrollment of the first 50 patients now completed. We have further expanded the study to 100 patients to broaden the data set supporting adoption and long-term market expansion. It is also notable that scientific recognition of this work continues to build. Data from Dr.

Stefano Spiezia of Naples, Italy were presented in a podium session at the North American Society of Interventional Thyroidology, or NASIT, in March, which demonstrated remarkable results. Data presented from durable 15- to 22-month results showed 74% volume reduction of treated benign thyroid nodules with overwhelming patient satisfaction reported. Continued volume reduction improvements were seen from 1 month through 22 months with no regrowth of nodules at 15 to 22 months. In parallel with the PRECISE-BTN study, we are continuing to expand the clinical scope of the Vybrance platform through our research collaboration with the University of Texas MD Anderson Cancer Center.

Under this collaboration, we are conducting a first-in-human feasibility study evaluating nsPFA for the treatment of papillary thyroid microcarcinoma, PTMC, on up to 30 patients at 2 sites, and we are happy to announce that first patient enrollments were completed in Q1. We continue to expect to complete enrollment by year-end 2026. With that, I will turn the call over to Jon to speak about our first quarter financial results. Jon?

Jon Skinner: Thanks, Paul. Now I will highlight our GAAP and non-GAAP financial results. I encourage listeners to review Monday's earnings release for a detailed reconciliation of non-GAAP measures to the most comparable GAAP measures. In the first quarter, we generated revenues comprised of both nPulse Catheter and Vybrance disposable sales. Total revenue was $401,000 and cost of product revenue was $370,000 for the quarter. Total GAAP costs and expenses for the quarter increased by $1.6 million to $19.6 million compared to $18 million in the prior year period. The increase in GAAP costs and expenses was primarily driven by increased investment in our clinical programs, partially offset by lower stock-based compensation expense.

To remind everyone, non-GAAP costs and expenses exclude stock-based compensation, depreciation and amortization as well as nonrecurring costs. Total non-GAAP costs and expenses in the first quarter of 2026 increased by $4.7 million to $17.4 million compared to $12.7 million in the prior year period. The expected increase was driven by increasing clinical trial, product development and market development activity. GAAP net loss in the first quarter of 2026 was $18.6 million compared to $16.8 million in the prior year period. Non-GAAP net loss in the first quarter of 2026 was $16.4 million compared to $11.4 million in the prior year period.

As of March 31, 2026, cash and cash equivalents totaled $68.3 million compared to $80.7 million as of December 31, 2025, representing a decrease of $12.4 million versus the prior quarter. Cash used in operating activities during the first quarter of 2026 was $14.6 million compared to $13.5 million used in the prior year period and $14.8 million in Q4 of 2025. As we discussed last quarter, we completed important corporate housekeeping by filing a $200 million shelf registration, all of which is available. In addition, the company has an ATM program in effect with approximately $60 million of availability as of March 31, 2026.

We have received Board of Directors' approval for interested executives and Board members to participate in our ATM program. Our Co-Chairman of the Board and our CEO and Co-Chairman have both indicated they are likely to purchase shares in the near term. Cash usage aligns with investment expenditures in pivotal trials, device scaling and market development. Expense growth remains deliberate and focused on long-term value creation. We continue to maintain ample liquidity to fund operations and clinical programs through major inflection points during 2026. With that, I will now turn it back over to Paul for his closing remarks.

Paul LaViolette: Thank you, Jon. This was a defining quarter for Pulse Biosciences. We sharpened our strategic focus on electrophysiology, delivered landmark clinical outcomes at Heart Rhythm 2026 and AF Symposium that reinforced the durability and efficiency of our technology and commenced enrollment in our U.S. IDE pivotal trial for our cardiac catheter program. Today, resulting from those efforts, we announced a tightened time line for anticipated completion of enrollment in our paroxysmal AF pivotal study. We strengthened the team supporting this mission, and we continue to advance our surgical and percutaneous programs in a disciplined manner aligned with our priorities.

Our path forward is clear, enroll and complete our pivotal trials, finalize our CE Mark submissions and continue to advance our partnership pipeline, all while maintaining the financial discipline to fund the company through the milestones that will define its future. This disruptive nsPFA technology we are advancing has the potential to change how ablation is performed across multiple disease states. And we believe that executing toward those near-term milestones will unlock that potential for patients, physicians and shareholders alike. Thank you for your continued support. Now joining us for the question-and-answer session are Bob Duggan, Co-Chairman of the Board, and for her first earnings call with Pulse Biosciences, our Chief Operating Officer, Liane Teplitsky.

Operator, please open the call for questions.

Operator: [Operator Instructions] We have the first question comes from the line of Suraj Kalia of Oppenheimer.

Suraj Kalia: Gentlemen, congrats on all the progress and the excitement at HRS. Paul, many calls going on. So please forgive me, I'll ask all my questions together. First, did you highlight the number of sites that are as part of the clinical trial? The limits to each site because you don't want too much concentration. And finally, if these patients are consciously sedated or general anesthesia.

Paul LaViolette: Thank you, Suraj. And yes, we are happy to take all your questions at once. Regarding the number of sites, we have approval for up to 30 sites, and that's important in part because it determines how many total rolling patients can be advanced in the study, and that affects the total number of patients that we can enroll, bringing that number up to 215. So total number of sites is 30.

We do not anticipate reaching that many sites just based on the total size of the study enrollment, the likelihood that a number of sites entering early in the protocol will, as you allude to in your second question, enroll at or close to the limit of their total enrollee allocation. And as a result of that, we're likely to involve active sites less than the number that we were allowed in our protocol of 30. As it relates to the limits per site, you're right. Every protocol limits the number of sites based on a percent of total so that there's not an unbalanced skew toward too few enrolling locations.

And that number is typical in this study as it is with many others. Usually, it's around 15% to 20% of total enrollment is the cap for an individual site, and that is the case here, which limits our sites to between, let's just say, the low 20s of patients per site maximum. And then as it relates to our anesthesia protocol, you raised a really good question because conscious sedation is a likely viable sedation protocol for these patients. We've seen that in Europe, and we're quite enthusiastic about the potential for lower sedation long term, particularly as we enter the U.S. market and migrate patient therapies to the ambulatory surgery setting.

That being said, the protocol in the pivotal study calls for general anesthesia.

Operator: [Operator Instructions] We have the next question comes from the line of Anthony Petrone from Mizuho.

Anthony Petrone: Congrats on a strong start to the year and the 2 good medical meetings, AF Symposium, HRS. Maybe taking it from HRS, the podium presentation, Dr. Reddy, maybe a little bit of noise that crept into the dialogue there at HRS relative to AF Symposium, sort of the idea that as we expand to more sites in the U.S., we potentially enroll a somewhat sicker patient population in the U.S., that we can see at least some degradation to the durability statistics that we saw out of the early feasibility study. So maybe just walk through the expectations for the capability to maintain durability, how continuous mapping can potentially help to improve that.

And any risk that there may be just from the differences in patient populations. And I'll have one quick follow-up.

Paul LaViolette: Thanks, Anthony. Very good question. We're very pleased with the data. The data set so far has been extremely strong. And obviously, just to remind folks, at 6 months, 100% efficacy against our primary endpoint of rhythm control as measured by Holter monitor at that 180-day point. Same thing at 12 months, 96%, and of course not a primary endpoint per se, but a broader measure of efficacy would be the data that we represented in our Kaplan-Meier curve of 90% success with respect to freedom from atrial fibrillation, a flutter and atrial tachycardia. So those are the numbers that we're starting with.

As it relates to the comparison of patient severity between the European feasibility study and the pivotal study, for the most part, there is no difference. These are both principally paroxysmal patients. A patient enrolled in the European feasibility study was by definition, per his or her medical record, a paroxysmal patient. The same severity measure will be applied in the United States. As it relates to some changes, let's say, in the population background, you will see, just based on moving to the United States and enrolling the vast majority of patients in the U.S., you will see minor changes in factors such as BMI, right?

The United States patient population is slightly heavier, and so we would expect the BMI which was 28 in Europe to go up in the U.S., but that's not a significant risk factor. The CHADS score, which is an important cardiovascular measure was relatively low. That will be consistent in the U.S. based on a paroxysmal population. And other factors in the medical history, whether it's hypertension or heart failure, we expect to have a relatively generic paroxysmal patient population, most notably with a relatively near-term onset of atrial fibrillation typically in the 1- to 2-year time frame.

So I think overall, the patient population, while representing the U.S. population and maybe a little bit less healthy is not representing, I'll call it, a higher risk factor than the U.S. And therefore, degradation is not to be expected. This is a pulmonary vein isolation strategy using a highly effective novel energy, which we've now seen evidence that produces a really impressive ablation and impressive electrical isolation. We've treated more patients in Europe actually than we'll enroll in the United States. The endpoints that we're using in this case of freedom from AF as measured by Holter are the same. So the same endpoints.

And I would also say the sites that we're moving to, while we will have more sites in the United States, we use multiple sites, multiple operators in Europe. And the sites that we're going to in the United States represent the best in the world. So we believe that -- and we've seen this, I think, early on in our enrollment experience. We believe that we are going to see outstanding clinical results. Physicians are, I'd say, rapidly assimilating our technology into their workflow, and it's performing the way we expected it to in the U.S., based on how we observe those cases performed in our European sites. Lastly, I think you make a great point about mapping.

Mapping is now tightly integrated, as we've mentioned, with the Abbott EnSite system. That mapping, I'll call it, refinement, that fidelity provides our U.S. pivotal trial operators with a very high degree of precision location of the catheter, enabling them to localize catheter placement and ablation placement very rapidly in our procedures and very accurately. And so we think the risk of experiencing a meaningfully different outcome in the U.S. is managed well by all of these consistencies between Europe and the U.S. and that we don't see the introduction of a meaningful new risk that would dilute expected clinical performance.

My last comment there would be success is not defined in our case explicitly by a specific number that is 96% or 95%. We have we have the potential here to redefine the way atrial fibrillation is treated, the workflow, the efficiency associated with this technology, which we see, of course, in an acute way, we don't need follow-up data for that. That is a dramatic change. This is a significant disruptive technology in the hands of physicians going against the #1 most common arrhythmia in medicine. And I do believe we have something that's very significant here.

And it's going to be a combination of both acute and long-term outcomes that will reinforce that for us coming out of the U.S. trial.

Anthony Petrone: And just the follow-ups in here real quick would be just to confirm in the pivotal study here, IDE study, will EnSite be the only mapper, or will you bring in additional mapping technologies? And then a quick one just on soft tissue ablation, papillary thyroid microcarcinoma, new collaboration with MD Anderson. Maybe just a high level on the underlying TAM opportunity on the carcinoma side of the equation for the thyroid. Congratulations again.

Paul LaViolette: Thank you very much, Anthony. Yes, on EnSite, based on the speed of enrollment and the availability of EnSite, it would appear today that EnSite will be the most common, predominant and likely the only system used in our IDE. That is against the backdrop that our technology really will work with multiple mapping systems. We have used different mapping systems. In fact, the European feasibility data set is a compilation of patients treated using 3 different mapping systems, and we would integrate with not only different systems over time, but because of the number, we have 12 sensors built into our device, we have now a magnet for electroanatomical connectivity, if you will, to the mapping system.

So our system is capable now of higher fidelity mapping and navigation than we saw in our European data set. But principally, we expect EnSite to be the system used. As it relates to the PTMC opportunity or papillary thyroid microcarcinoma, that is the single most commonly diagnosed thyroid cancer. And so if we think about the TAM, to your question, the TAM for soft tissue ablation focused on benign thyroid nodules begins with the annual diagnosis of about 250,000 patients with benign nodules. So converting from that, approximately 150,000 thyroidectomies are performed. And we believe the benign indication goes after some combination of surgical conversion and treatment of patients avoiding surgery now and going into active surveillance.

So if you think about 250,000 as the annual diagnostic volume in benign nodules. If we flip over then to papillary microcarcinoma, that number is lower. That number is about 25,000. And if we then take -- because this is a slow-growing non-metastasizing cancer, which makes it very amenable to our therapy, we believe, there is also a very large prevalence pool of papillary microcarcinoma patients who are living with cancer and who would want that cancer treated if a minimally invasive approach proved effective. And so the way we think about the addressable market there is that you have those 25,000 new diagnoses, you have a large prevalence pool seeking treatment, you're likely to yield perhaps 50,000 incremental procedures.

So if we think about the TAM driven by the benign indications, that could be 100,000 to 200,000 based on annual incidents and conversion of patients from a watchful waiting pool, add a number that might be an incremental 25% to 35% of that population based on the addition of a papillary microcarcinoma indication in the future.

Operator: Thank you. That will conclude our question-and-answer session. I will now turn the call back over to Mr. Paul LaViolette, CEO and Co-Chairman, sir, for closing remarks.

Paul LaViolette: Well, thank you, operator, and thank you all for joining us on our first quarter earnings call. We look forward to providing updates on our very active operating plans in upcoming financial conferences in Q2 and on our Q2 earnings call later this summer. Thank you all very much.

Operator: Ladies and gentlemen, that concludes today's call. Thank you all for joining. You may now disconnect.