Letter from the Editor in Chief

Dr. Mansour reports the reception of research grants from Abbott Laboratories, Biosense Webster, Johnson & Johnson, Boston Scientific, Medtronic, Pfizer, Boehringer Ingelheim, and SentreHeart. He is also a consultant for Abbott Laboratories, Biosense Webster, Johnson & Johnson, Boston Scientific, Janssen, Medtronic, Phillips, Novartis, and SentreHeart and reports an equity relationship with EPS Solutions. All aforementioned relationships are in the area of atrial fibrillation; Dr. Mansour additionally reports an equity relationship in the area of ventricular fibrillation with NewPace Ltd. Dear Readers,


Dear Readers,
Despite the difficulties and challenges that occurred in medicine in 2020, cardiac electrophysiology continued to progress and many high-impact studies were published this past year. Below, I highlight a few that I believe will impact the field going forward.
The Prospective Randomized Comparison of Subcutaneous and Transvenous Implantable Cardioverter-defibrillator (ICD) Therapy (PRAETORIAN) trial was presented at the virtual HRS Science 2020 event and compared subcutaneous and transvenous ICDs in patients with indications for an ICD but not for pacing. The primary study endpoint was a composite of device-related complications and inappropriate shocks and 426 and 423 patients were randomized to the subcutaneous ICD and transvenous ICD groups, respectively. After a median follow-up period of 49 months, the primary endpoint was met and subcutaneous ICDs were found to be noninferior to transvenous ICDs in this investigation. This finding will likely result in an increased shift in clinical practice favoring subcutaneous ICDs for implantation.
Pulsed-field ablation has continued to make waves in 2020. At the Atrial Fibrillation (AF) Symposium in January 2020, Reddy al. presented data from a first-in-human trial of a lattice-tip, temperature-controlled radiofrequency ablation catheter, focusing on pulmonary vein isolation (PVI) outcomes and linear lesion durability. A total of 60 patients were treated at three European centers using this novel technology; some underwent tricuspid and mitral isthmus ablation in addition to PVI. Two important findings arose from this investigation: first, the rate of durable PVI at remapping study was 96.3%, while, at 291 ± 106 days of follow-up, the 12-month Kaplan-Meier estimate for freedom from all atrial arrhythmias was 94.4% ± 3.2%. The same group reported the results of the PersAFOne study as well, which examined the use of pulsed-field ablation to treat persistent AF with PVI plus posterior wall ablation. Here, 15 patients with persistent AF were enrolled in two European centers and underwent PVI and posterior left atrial wall ablation. This pilot study supported the view that pulsed-field ablation is a promising modality and facilitates ultrafast ablation of AF with no major complications.
Also during HRS Science 2020, the acute results of the PULSED AF study, a nonrandomized, prospective, multicenter, global premarket clinical study performed in Australia, Canada, the United States, and Europe, were presented. This trial evaluated the PulseSelect system (Medtronic, Minneapolis, MN, USA), which delivers pulsed electric fields through a circular multielectrode array catheter for PVI. Ablation in patients with either paroxysmal or persistent AF led to acute electrical isolation in 100% of this population without tamponades, strokes, or phrenic nerve injuries. Upon conclusion, data on the rate of arrhythmia-free survival at 12 months along with prespecified secondary and ancillary endpoints such as procedural outcomes, quality of life, and arrhythmic symptoms are anticipated.
Two large multicenter studies on the ablation of persistent AF were presented in 2020. The STOP Persistent AF global prospective multicenter study was presented at the 2020 AF Symposium, with Calkins et al. offering 12-month efficacy and safety results. This study found that cryoballoon ablation using the Arctic Front Advance™ system (Medtronic) is safe and effective in the ablation of persistent AF. The 12-month efficacy rate of ablation using this technology was 55%. The study confirmed the hypothesis that, to achieve higher success rates when treating persistent AF, adjunctive ablation in addition to PVI will likely be required.