Niraj Sharma: Hi everyone this is Doctor. Sharma and welcome back to EP Edge Journal Watch. Today's issue is a rapid tour through studies that actually change what we do in the lab. We start with pulse field ablation and you will hear one theme over and over: PFA is not only a new technology, it is protocol driven. Then we move to stroke prevention and device durability, a new amulet veritas trial and a new ICD lead platform.
After that, two very practical EP lab papers, a simple pacing maneuver that can streamline diagnosis, and a leadless pacemaker infection case that reminds us leadless does not mean immune to infection. And we close with something we don't talk about enough: occupational hazards in electrophysiology. Alright, let's start with Verapulse because it is a master class in how workflow can dominate outcomes. This VariPulse paper is basically a post approval workflow signal story. The system is an irrigated variable loop circular PFA catheter, and the clinical concern was neurovascular events, stroke or TIA, early after launch.
Across U. S. Procedures from December 2024 through August 2025, more than six thousand eight hundred cases, the reported neurovascular event rate dropped from about three percent to about zero point two eight percent. That's nearly a tenfold reduction. Now here's the key.
The paper argues this is not PFA is unsafe. What changed was the procedure phenotype. Mean applications fell roughly from the low 30s to the low 20s per case, and the emphasis became don't stack lesions, don't deliver unnecessary repeat applications at the same spot. Irrigation was also adjusted, higher flow during energy delivery. But in the post pause comparison, the irrigation difference itself wasn't the dominant statistical driver.
So the teaching point is uncomfortable but important. Early safety signals can be workflow mediated. If you want PFA to be safe, you standardize dosing behavior, limit unnecessary applications, cautious sheath management. The idea of protocol sensitivity shows up again in the ElectroPulse first in human experience. ElectroPulse is a different concept, a smaller variable loop catheter designed to integrate mapping and ablation contact sensing, irrigation, simplified workflow.
In a prospective two center study of 60 AF patients, they ran two sequential cohorts. Cohort one used a standard protocol, cohort two used a modified protocol. Sequential overlapping bipoles, acute endpoints were excellent in both pulmonary veins isolated, and posterior wall isolation if performed, basically 100%. But the striking thing was efficiency and durability. With the modified protocol, applications and procedure, time dropped.
Six month recurrence was similar but in the subset that came back for redo. Durability looked dramatically better with the modified protocol. So again, same platform direction but outcomes hinge on how you deploy energy. Alright, now we go to right sided CTI ablation with a new focal PFA catheter, the Farapoint. The CT isthmus sits right over the epicardial right coronary artery.
PFA is non thermal, but it can depolarize vascular smooth muscle. Smooth muscle depolarizes, calcium influx happens, and you can get intense vasoconstriction When investigators looked for spasm with angiography, it wasn't rare, it was frequent, almost the expected physiologic response when you actually imaged the vessel. Now the practical question is how do you prevent it? And here's the key operational details: high dose nitroglycerin not cath lab chest pain doses. High dose, centrally delivered a three mg bolus into the right atrium about a minute before the first application, then repeated two mg doses every two minutes during lesion delivery total dose not exceeding nine milligrams.
And because those are big nitrate doses, the protocol included blood pressure support, phenylephrine pretreatment to preserve aortic pressure while relaxing coronary smooth muscle. Now here's the part that should make everyone pause. Even if you blunt acute spasm intracoronary imaging, follow-up suggests there may be localized structural remodeling at the ablation adjacent segment at around three months wall area increase and luminal area reduction. So PFA should be considered nonthermal but not nonvascular, which is a perfect bridge into the Farapoint study because that trial essentially bakes in coronary protection as part of the workflow. This is the ADDvantage AF sub study comparing typical flutter ablation approaches, but it's not PFA versus RF in the abstract.
It's a very specific comparison: standard irrigated RF catheter in phase one versus a novel bipolar linear PFA catheter in the next phase. And importantly this CTI work was done in the context of AF ablation workflow, AF ablation first using a multi electrode PFA platform, then CTI adjunct ablation with either RF or the linear bipolar PFA catheter. Now the operational headline: Coronary safety protocol. Before PFACTI ablation, patients received a vasopressor bolus followed by high dose intravenous nitroglycerin. That's not a footnote.
That is the technique. Efficacy was excellent. Acute CTI block essentially universal in both groups. Efficiency favored PFA. CTI ablation time dropped on the order of minutes with PFA compared to longer with RF and with the protection strategy in place, the trial reports no clinical manifestation of coronary spasm during the PFA CTI approach.
So the EP edge takeaway is: Linear bipolar PFA can be a CTI tool when dosing is constrained and coronary prophylaxis is standardized, but it's important to remember the possibility of long term coronary artery lumen reduction. Alright, let's pivot to Structural Solutions, Amulet three sixty, because this is about engineering out failure. Veritas evaluates Amulet three sixty, a next generation dual seal left atrial appendage occluder. The stated motivation is simple: prior devices work, but peri device leak, device related thrombus, and pericardial effusion remain important failure modes. In this cohort, about four hundred AF patients with high stroke and bleeding risk profiles enrolled.
Implant success was essentially one hundred percent, early safety through discharge was excellent, and at forty five days imaging showed strong sealing performance, a very high proportion with no leak and essentially universal meeting of the leak threshold definition. Now the right way to interpret this is, this is an early mechanical performance study. The big question is durability, late leaks, device related thrombosis, long term outcomes. But as an engineering thesis it's clear: design is shifting toward eliminating common failure modes. Next, hardware durability in the ICD LAN the LEADER trial.
LEADER evaluates the Omnia Secure Defibrillation lead built on the idea that transvenous leads are often the long term failure point. In a large cohort with roughly three years of follow-up, implant success was high. Freedom from major lead related complications at three years was in the mid-90s. Therapy performance looked credible, ATP efficacy strong and inappropriate shock rates low over time. This isn't a superiority trial, but it establishes a plausible durability profile for a design that is explicitly trying to reduce mechanical failure.
Alright now let's go back into the EP lab because this pacing maneuver is the kind of thing that saves real time on real cases. This paper proposes a very simple pacing maneuver to distinguish AV nodal from septal accessory pathway ventriculoatrial conduction. Here's the maneuver. You pace from the basal right ventricle and measure a timing interval (call it SA1), Then you move the catheter just two to three centimeters deeper toward the apex and measure again, SA2. And the rule is clean.
If SA1 is greater than SA2, that's a nodal response. If SA1 is less than SA2, that favors an accessory pathway response. In their cohort, the separation was striking. Accessory pathway patients had negative delta, non accessory pathway patients had positive delta, with complete separation in that dataset. This is exactly the kind of maneuver that is teachable, fast, and potentially scalable across labs because it leans on geometry rather than perfect catheter position.
Next, leadless pacemakers and this is the reminder none of us want, but all of us need. This issue includes the first reported infection involving a leadless atrial pacemaker, a high risk patient, prior MRSA, cardiac implanted device infection, immunosuppression, diabetes, presented with MRSA bacteremia months after implantation. Imaging mattered. TEE identified a mass attached to the device, and intracardiac echo confirmed it. Management was percutaneous extraction via femoral approach under ice guidance, but here's the part to remember: after extraction, residual infected material remained, bacteremia persisted, and they used an aspiration system, AlphaVac, again under ice guidance, to remove adherent infected material.
Cultures confirmed MRSA on the device. Bacteremia cleared after aspiration. So the takeaway is not that leadless pacing is a bad idea, it's that the shortcut phrase leadless equals infection proof is dangerous. Leadless reduces infection risk. It does not eliminate it.
And the broader context matters. Large ventricular leadless registries have extremely low device infection removal rates. But atrial leadless infection raises an open question: Is the atrial environment more vulnerable in certain hosts? In the highest risk patients, a stage strategy may be smarter: ventricular leadless first post extraction, then atrial modular pacing later, once infection risk stabilizes. All right, we close with the physician occupational hazards because the operator is part of the system.
This global HRS member survey is the kind of paper that should change policies, not just personal habits. It reports meaningful rates of cancer, orthopedic injury, radiation associated conditions like cataracts, and serious pregnancy related complications. This isn't only about discomfort, it's about workforce sustainability. If EP continues to increase procedural volume without redesigning ergonomics, shielding and workflow, we will lose operators, especially early career physicians and women in training. Operator protection isn't optional.
It's a patient care issue because sustainable operators deliver sustainable care. With that, we wrap this issue of Journal Watch. Thank you for listening to EP Edge Journal Watch. Full details, graphics and references are available on the EP Edge Journal Watch LinkedIn newsletter. This newsletter is also available on Substack at epedge.substack.com.
If you have questions or concerns you can reach me at epedgecastgmail.com Bye for now and take care.