From the Member Sections | The Evolution of Electrophysiology: 57 Years of Milestones
The field of invasive cardiac electrophysiology (EP) has witnessed extraordinary advancements over the past 57 years, beginning with the foundational recording of the His bundle electrogram in 1969 by Anthony Damato, MD. Around the same time, Dirk Durrer, MD, and Hein Wellens, MD, FACC, demonstrated in a patient with Wolff-Parkinson-White (WPW) syndrome that arrhythmias could be initiated and terminated by programmed electrical stimulation.
This journey is the labor of research and innovation, taking advantage of serendipitous findings, such as the inception of targeted interventions in arrhythmia therapy from the observation during surgical closure of atrial septal defects that procaine injection could affect the WPW pathway.
Continued advancements have revolutionized cardiac care with several key milestones highlighted here.
Milestone 1. A shift in the atrial fibrillation (AFib) treatment paradigm to early rhythm control offers not only symptom improvement but also mortality benefit. Historically, trials like RACE and AFFIRM performed decades ago had suggested equivalence of rate and rhythm control for AFib.
Recently, several landmark trials have challenged this approach. EAST-AFNET4 highlighted that early rhythm control, compared to rate control, of new AFib (less than one year) reduced both the composite primary outcome and individual rates of cardiovascular death, stroke and hospitalization for worsening heart failure (HF) and acute coronary syndrome (hazard ratio [HR], 0.79; 95% CI, 0.66-0.94). Of note, 86% of the rhythm control arm was managed by antiarrhythmic drugs alone.
The ATTEST and EARLY AF trials have shown the additional benefit of ablation over antiarrhythmic drugs (AADs) in decreasing progression to persistent AFib: risk of 2.4% with radiofrequency ablation vs. 17.5% with AADs at three years (p=0.009) and risk of 2% with cryoablation vs. 8% with AADs at five years (p=0.005).
Furthermore, there is growing evidence that early rhythm control decreased stroke risk, with the results from EAST-AFNET4 furthered by the latest trial using the Korean National Health Insurance database showing a 23% decrease in stroke risk with early rhythm control.
Milestone 2. The development of intracardiac echocardiography provided enhanced anatomic definition, facilitating more precise and fluoro-less procedures. This innovation laid the groundwork for a safer and more effective approach to cardiac interventions with its use spanning from ablations to extractions.
Milestone 3. The identification of intramural and 3D circuits in ventricular tachycardia (VT) and atrial flutters has deepened our understanding of these conditions, leading to more targeted and effective ablation. Ventricular arrhythmias remain an important source of mortality and morbidity with little progress in drug therapy, increasing the importance of catheter ablation.
For several decades the model set by animal and human studies centered on 2D scar-related reentrant circuits, leading to endocardial mapping of VT being adopted clinically. This technique only identified the critical isthmus in 20% to 30% of tachycardias despite advancements in high-resolution mapping technologies.
The model was redefined in 2020 by Tung, et al., into a 3D circuit in a figure-8 shape that involves more than one layer, with a mid-myocardial limb in 96% of cases. This novel endocardial and epicardial mapping with inferences about the mid-myocardial surface from the activation gaps in the endocardium and epicardium during VT allowed a breakthrough 56% improvement in catheter ablation success.
Milestone 4. The advent of novel pacing technologies now support a wide range of patients and indications. Biventricular pacing, used to correct left ventricular dyssynchrony, has emerged as a crucial therapy for HF, promoting the remodeling of the left ventricle and enhancing cardiac function.
With a significant percentage remaining nonresponsive to this technology (20% to 30%), conduction system pacing has emerged as another option for synchronization of cardiac rhythms, further advancing patient care. Leadless pacing technology has eliminated some of the complications associated with traditional pacemakers, offering a less invasive option for patients.
Milestone 5. The incorporation of artificial intelligence (AI) into digital health, ambulatory monitoring and ablation mapping has expanded the capabilities of data collection, access to therapies, and even ablation success. The increase in detected AFib from wearables foretells a strain on electrophysiologists, who are already the scarcest among all subspecialties per capita in the U.S.
Thus, AI technologies that not only present diagnostic data but also support AFib treatment, for example by guiding titration of AADs (SafeBeat Rx, Inc.) can offer immediate practical benefit for clinical workflows over traditional black-box algorithms.
Category III CPT codes have emerged for 2025 to support billing for these novel technologies, including AI-based QT interval (XX19T) and algorithmically generated 12L ECGs from reduced lead ECGs (XX20T, XX21T, XX22T). For ablations, tailored AFib has shown the superiority of AI-assisted mapping in both persistent and longstanding persistent AFib, with a termination rate of acute AFib of 66% vs. 15% (p<0.001) and a rate of 12-month freedom from AFib of 88% vs. 70% (p<0.001).
It remains to be assessed whether the resulting massive debulking of the left atrium and right atrium from ablated areas, further facilitated by efficient technologies such as pulse field ablation, would create frequent functional and electrical atrial standstill, not commonly encountered previously.
Future Sparks: New Horizons in Electrophysiology
AFib Awareness Month
September is Atrial Fibrillation Awareness Month – a reminder to help raise awareness of AFib among clinicians and patients. On the clinician front, be sure you're up to speed with ACC's free, self-paced online course Early Onset of Atrial Fibrillation & the Contemporary Use of Antiarrhythmic Drugs.
Join Suneet Mittal, MD, FACC, for Quick Tips on Utilization of Antiarrhythmic Drugs in Atrial Fibrillation Management, a concise overview of the most recent clinical evidence and guideline recommendations for managing and treating AFib. Listen to AFib-focused ACC CardiaCast podcasts and look for new activities launching this fall. Learn more.
Be sure to download the ACC's AnticoagEvaluator app enhanced with new recommendations from the 2023 ACC/AHA Guideline for the Diagnosis and Management of Atrial Fibrillation. On the patient front, explore CardioSmart's Atrial Fibrillation page and all the infographics, action plans, decision aids, fact sheets, videos and more.
Despite remarkable progress over the last half-century, several issues remain to be addressed in EP. Understanding the pathophysiology of AFib is paramount to developing more effective treatments. There is a pressing need for single-shot therapies for arrhythmias, which would simplify treatment protocols and improve patient outcomes.
Electroporation, as a nonthermal and tissue-selective energy source, is poised to create irreversible cell death that is tissue specific and represents a great advancement since the first direct current shock in 1980 to ablate arrhythmias by Melvin Scheinman, MD, FACC.
The advent of pulse field electroporation with nonthermal energy that is tissue-specific is one example of single-shot therapy that has proven equal efficiency and improved safety compared to current technologies, though with its own challenges such as hemolysis and vasospasm.
Robotic and automated mapping and ablation systems are also expected to enhance precision and efficiency in arrhythmia management. Moreover, the use of noninvasive technologies to map arrhythmias can transform both the diagnostic and treatment landscape. On the implantable side, the development of auto-rechargeable leadless devices, including defibrillators and biventricular pacemakers, promises to reduce the need for invasive procedures and extend device longevity.
In conclusion, the young field of EP has seen considerable advances, from early discoveries that paved the way for targeted interventions to the integration of advanced digital technologies that continue to push the boundaries of what is possible in cardiac care. Peering into the horizon, we foresee a future where relentless innovation heralds unprecedented breakthroughs in our quest for heart health.
This article was authored by Estelle Torbey, MD, FACC, electrophysiologist at Brown University/Lifespan in Providence, RI, and Rachita Navara, MD, FACC, electrophysiologist at Seton Medical Center, San Francisco, CA. They are members of ACC's Electrophysiology Member Section.
Find your Member Section here and connect with members who share a similar interest, specialty or career stage and explore all the ways you can engage with the College.
Clinical Topics: Arrhythmias and Clinical EP, Cardiovascular Care Team, Noninvasive Imaging, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Echocardiography/Ultrasound
Keywords: Cardiology Magazine, ACC Publications, Electrophysiologic Techniques, Cardiac, Echocardiography, Catheter Ablation, Radiofrequency Ablation, Electric Stimulation
