McLeod, Christopher J

ABSTRACT Background Pulsed field ablation (PFA) is an emerging non‐thermal ablation modality with proven safety in atrial arrhythmia ablation. However, data on its performance for ventricular arrhythmias (VA) remain limited. Objective To evaluate the feasibility, safety, and efficacy of PFA for complex VA in a multicenter real‐world US registry. Methods This retrospective study included consecutive patients undergoing PFA for ventricular tachycardia (VT) or premature ventricular contractions (PVCs) at three Mayo Clinic centers (April 2024 to July 2025). The primary feasibility outcome was the successful delivery of PFA lesions to the intended target substrate. Primary efficacy outcomes included acute procedural success; sustained VT recurrence requiring implantable cardioverter‐defibrillator (ICD) shocks or multiple antitachycardia pacing therapies; and ≥ 80% reduction in PVC burden. Safety outcomes included procedural complications, valvular function, thromboembolic events, renal function, and conduction disturbances. Results Twenty‐six patients were included (13 PVC, 13 VT). Acute success was achieved in all VT ablations (69.2% complete; 30.8% partial) and in 92.3% of PVC ablations. Complications occurred in 11.5% of patients (transient LBBB [ n = 1] and vascular complications [ n = 2]). No thromboembolic events, intracardiac thrombus, or acute kidney injury were observed. Lesions near the mitral valve apparatus did not worsen mitral regurgitation, including in patients with pre‐existing valve disease. After a median follow‐up of 365 days, one patient experienced VT recurrence requiring ICD shocks. Estimated recurrence‐free survival after VT ablation was 61.5% at 12 months; 58.3% of PVC patients achieved ≥ 80% burden reduction. Conclusion PFA for VA appears feasible and acutely effective, with a low rate of procedure‐related complications. While acute success was high, long‐term outcomes were acceptable for VT ablation and relatively modest for PVC ablation, highlighting the need for continued refinement of technology and energy‐delivery strategies. Larger prospective studies are warranted.

Abstract Aims The clinical significance of early recurrences during the blanking period following pulmonary vein isolation (PVI) remains uncertain, particularly after pulsed field ablation (PFA). This study aimed to evaluate the prognostic impact of early recurrences at 30-, 60-, and 90-day thresholds on outcomes following PFA for atrial fibrillation (AF). Methods and results Consecutive patients who underwent PFA for AF across multiple centres within the Mayo Clinic health system were included. The primary endpoint was AF-free survival. Kaplan–Meier and multivariate Cox regression analyses were performed to compare outcomes between patients with and without early recurrences using 30-, 60-, and 90-day thresholds. A total of 1162 patients were included. The estimated AF-free survival at 1 year was 70%. Early recurrences within 30-, 60-, and 90-days post-ablation were significantly associated with late recurrences beyond 90 days (hazard ratio [HR] 5.9, 95% confidence interval [CI] 4.4–7.9, P < 0.01; HR 6.6, 95% CI: 5.0–8.6, P < 0.01; and HR 9.1, 95% CI: 7.0–11.7, P < 0.01, respectively). These findings remained significant among patients undergoing continuous rhythm monitoring. Early recurrences within 30 days in this subgroup were significantly associated with a 1-year AF burden >1% or the need for repeat AF ablation (odds ratio 25.0, 95% CI: 6.6–126.8, P < 0.01). Conclusion Early recurrences following PFA are strongly predictive of long-term arrhythmia recurrence and are unlikely to represent transient inflammatory phenomena. Accordingly, the applicability of the conventional blanking interval after PFA should be reconsidered.

Background There is a global mismatch between the number of adults with congenital heart disease and adult congenital heart disease (ACHD) cardiologists, potentially impacting patient outcomes. This survey explores factors influencing trainees and cardiologists' career choices in ACHD. Methods An online, anonymous global survey on demographics, ACHD as a career choice, encouraging and deterring factors assessed via a 5‐point Likert scale and open‐ended questions on recommending ACHD was distributed through targeted emails and social media. Responses meeting a 75% completion criterion were analyzed using descriptive statistics and thematic analysis. Results Among 811 included responses, most were from women (53.5%), aged 31 to 40 years (48.3%), White individuals (43.3%), non‐Hispanic individuals (85%), from outside the ACHD field (79.0%), and from North America (42.7%). Only 30.9% of non‐ACHD physicians considered specializing in ACHD despite 78.9% recommending it. Encouraging factors included awareness of ACHD significance, mentor influence, and clinical exposure. Key deterrents were inadequate financial incentives, limited job opportunities, and lengthy training. Regional variations showed that longer training duration and lack of compensation incentives were the main deterrents in North America. Suggested solutions included structured training programs, salary improvements, and early ACHD exposure during medical education. Conclusions Less than a third of respondents considered ACHD as a career largely due to inadequate financial incentives, limited job opportunities, and long training duration. Addressing these barriers could enhance recruitment and help meet the growing demands of the ACHD population.

BACKGROUND: The outcomes of catheter ablation for atrial fibrillation in adults with congenital heart disease are not well described. METHODS: In a retrospective study of adult patients with congenital heart disease who underwent catheter ablation for atrial fibrillation between 2000 and 2020 at Mayo Clinic, procedural characteristics and outcomes were collected. The primary outcomes were atrial arrhythmia (AA) recurrence following a 3-month blanking period and repeat ablation. An arrhythmia clinical severity score was assessed pre- and post-ablation based on the duration of arrhythmia episodes, symptoms, cardioversion frequency, and antiarrhythmic drug use. RESULTS: One hundred forty-five patients (age, 57±12 years; 28% female; 63% paroxysmal atrial fibrillation) underwent 198 ablations with a median follow-up of 26 months (interquartile range, 14–69). One hundred ten, 26, and 9 patients had simple, moderate, and complex congenital heart disease, respectively. All patients underwent pulmonary vein isolation, and non–pulmonary vein targets were ablated in 79 (54%). AA recurrence at 12 months was 37% (95% CI, 29%–45%). On univariate analysis, increasing left atrial volume index was associated with higher odds of AA recurrence (odds ratio, 1.03 [1.00–1.06] per 1 mL/m 2 increment; P =0.05). Noninducibility of atrial flutter was predictive of decreased odds of AA recurrence (odds ratio, 0.43 [0.21–0.90]; P =0.03). A second ablation was performed in 43 patients after a median of 20 (interquartile range, 8–37) months. Arrhythmia clinical severity scores improved following ablation, reflecting a decrease in symptoms, cardioversions, and antiarrhythmic drugs. CONCLUSIONS: Catheter ablation of atrial fibrillation is feasible and effective in patients with adult congenital heart disease and reduces symptoms. Recurrence of AA frequently requires repeat ablation.

Background: Recognition of the causes of early mortality after atrial fibrillation (AF) catheter ablation is essential for the improvement of patient safety. This study sought to determine the causes of early mortality (≤90 days) after AF ablation. Methods: We performed a retrospective analysis of AF ablation from January 1, 2013, to December 1, 2021 at the Mayo Clinic (Rochester, Phoenix, and Jacksonville). Causes of death were identified through a comprehensive chart review of the electronic health record from within the Mayo Clinic system and outside records when available. Results: A total of 6723 patients were included in the study. The 90-day all-cause mortality rate was 0.22% (n=15). Among all 90-day deaths, majority of the deaths (73.3%) did not have a direct relationship with the procedure. Sudden death was the most common cause of early death (20%), followed by peri-procedural stroke (13%), respiratory failure (13%), atrioesophageal fistula (13%), infection (7%), heart failure (7%), and traumatic brain injury (7%). The 90-day mortality rate directly due to AF ablation procedural complications was 0.06% (n=4). Conclusions: AF ablation procedure has a 90-day mortality of 0.22%, and the most common cause of early mortality was sudden death. The majority (73.3%) of early mortality was not directly associated with a procedural complication, and the mortality rate due to complications associated with the AF ablation procedure was low at 0.06%. Further studies are required to investigate causes and risk factors associated with sudden death in this patient population.

Background The objective of this international multicenter study was to investigate both early and late outcomes of cardiac resynchronization therapy (CRT) in patients with a systemic right ventricle (SRV) and to identify predictors for congestive heart failure readmissions and mortality. Methods and Results This retrospective international multicenter study included 13 centers. The study population comprised 80 adult patients with SRV (48.9% women) with a mean age of 45±14 (range, 18–77) years at initiation of CRT. Median follow‐up time was 4.1 (25th–75th percentile, 1.3–8.3) years. Underlying congenital heart disease consisted of congenitally corrected transposition of the great arteries and dextro‐transposition of the great arteries in 63 (78.8%) and 17 (21.3%) patients, respectively. CRT resulted in significant improvement in functional class (before CRT: III, 25th–75th percentile, II–III; after CRT: II, 25th–75th percentile, II–III; P =0.005) and QRS duration (before CRT: 176±27; after CRT: 150±24 milliseconds; P =0.003) in patients with pre‐CRT ventricular pacing who underwent an upgrade to a CRT device (n=49). These improvements persisted during long‐term follow‐up with a marginal but significant increase in SRV function (before CRT; 30%, 25th–75th percentile, 25–35; after CRT: 31%, 25th–75th percentile, 21–38; P =0.049). In contrast, no beneficial change in the above‐mentioned variables was observed in patients who underwent de novo CRT (n=31). A quarter of all patients were readmitted for heart failure during follow‐up, and mortality at latest follow‐up was 21.3%. Conclusions This international experience with CRT in patients with an SRV demonstrated that CRT in selected patients with SRV dysfunction and pacing‐induced dyssynchrony yielded consistent improvement in QRS duration and New York Heart Association functional status, with a marginal increase in SRV function.

Background: Mitral annular disjunction (MAD) has recently been recognized as an arrhythmogenic entity. Data on the electrophysiological substrate as well as the outcomes of catheter ablation of ventricular arrhythmias in patients with MAD is limited. Methods: Forty patients with MAD (mean age 47±15 years; 70% female) underwent catheter ablation for ventricular arrhythmias. Detailed clinical, electrocardiographic, cardiac imaging, and procedural data were collected. Clinical outcomes were compared between patients who had substrate modification in the MAD area and those who did not. Results: Twenty-three (57.5%) patients had ablation for premature ventricular contractions, 10 (25%) patients for sustained ventricular tachycardia, and 7 (17.5%) patients for premature ventricular contraction-triggered ventricular fibrillation. Mean end-systolic MAD length was 10.58±3.49 mm on transthoracic echocardiography. Seventeen (42.5%) patients had preprocedural cardiac magnetic resonance imaging, and 5 (29%) patients had late gadolinium enhancement. Among the 18 (45%) patients who had abnormal local electrograms (low voltage, long-duration, fractionated, isolated mid-diastolic potentials) during electroanatomical mapping, 10 (25%) patients had abnormal electrograms in the anterolateral mitral annulus and/or MAD area. Substrate modification was performed in 10 (25%) patients. Catheter ablation was acutely successful in 36 (90%) patients (elimination of premature ventricular contraction or noninducibility of ventricular tachycardia). After a median follow-up duration of 54.08 (interquartile range, 10.67–89.79) months, premature ventricular contraction burden decreased from a median of 9.75% (interquartile range, 3.25–14) before the ablation to a median of 4% (interquartile range, 1–7.75) after the ablation ( P =0.03 [95% CI, 0.055–6.5]). Eight (20.5%) patients had repeat ablation for ventricular arrhythmias. Substrate modification of the MAD was associated with a trend toward lower rates of repeat ablation (0% versus 26.7%; P =0.16). Conclusions: Patients with MAD have a complex arrhythmogenic substrate, and catheter ablation is effective in reducing recurrence of ventricular arrhythmias. Substrate mapping and ablation may be considered in these patients.

Background: Optimal management of cardiac implantable electronic devices (CIEDs) in patients with Ebstein anomaly during tricuspid valve (TV) surgery is unknown. Thus, we aimed to characterize CIED management/outcomes in patients with Ebstein anomaly undergoing TV surgery. Methods: Patients at the Mayo Clinic from 1987 to 2020 with Ebstein anomaly and CIED procedure were reviewed for procedural details, complications, echocardiogram, and lead parameters. Five-year cumulative incidence of CIED complications were estimated using the Kaplan-Meier method. Results: Ninety-three patients were included; 51 were female, and mean age was 40.7±17.5 years. A new CIED was implanted in 45 patients at the time of TV surgery with the majority receiving an epicardial (n=37) CIED. Among 34 patients who had preexisting CIED (11 epicardial, 23 transvenous) at time of TV surgery, 20 had a transvenous right ventricular lead managed by externalizing the lead to the TV (n=15) or extracting the transvenous lead with epicardial lead implantation (n=5). Fourteen patients underwent CIED implantation (4 epicardial, 10 transvenous) without concurrent surgery. Placement of lead across the TV was avoided in 85% of patients. The 5-year cumulative incidence of CIED complications was 24% with no significant difference between epicardial and transvenous CIEDs (26% versus 23%, P =0.96). Performance of lead parameters was similar in epicardial and transvenous leads during median (interquartile range) follow-up of 44.5 (61.1) months. Conclusions: In patients with Ebstein anomaly undergoing TV surgery, the use of epicardial leads and externalization of transvenous leads to the TV can avoid lead placement across the valve leaflets. Lead performance and CIED complications was similar between epicardial and transvenous CIEDs.

Background: Patients with D-transposition of the great arteries and atrial switch have a high incidence of atrial arrhythmias. We sought to analyze the arrhythmia substrate, ablation strategies, and outcomes for catheter ablation in this population. Methods: An in-depth analysis of all clinical and procedural data in patients with D-transposition of the great arteries, atrial baffles, and atrial arrhythmia ablation was performed. Results: A cohort of 32 patients (72% male, mean age 38±7 years) underwent ablation for non-AV nodal reentrant tachycardia atrial arrhythmias, and 4 patients underwent AV nodal reentrant tachycardia ablation. Cavotricuspid isthmus flutter (CTI-flutter) was the most common arrhythmia, encountered in 75% of patients, followed by scar-related intraatrial reentrant tachycardia (non-CTI intraatrial reentrant tachycardia, 53%) and focal atrial tachycardia (focal atrial tachycardia, 6%). Among the 32 patients, 26 underwent 31 procedures at our institution. For patients with prior outside intervention, the index ablation at our institution revealed CTI-dependent flutter in 3/5 cases. However, redo ablation after an index ablation with demonstrated bidirectional CTI block revealed different/new arrhythmia substrates (80% non-CTI intraatrial reentrant tachycardia, 40% focal atrial tachycardia). Achieving bidirectional block across the CTI often required ablating on both sides of the baffle (retroaortic access, 81%; using a baffle leak, 11.5%; or transbaffle puncture, 7.7%). Combined approaches were necessary in 19% to reach the critical tissue. Acute procedural success was 81%, and recurrence was documented in 58% of patients. Despite recurrence, clinical arrhythmia burden was significantly reduced post-ablation ( P <0.001), with rare episodes, amenable to antiarrhythmic therapy. Redo ablation was required in 5 (19%) patients and uncovered new arrhythmia substrates. AV nodal reentrant tachycardia ablation also required transbaffle approaches in 3/4 patients. Conclusions: CTI-dependent flutter was the most common arrhythmia in patients with Dextro-Transposition of the Great Arteries and atrial switch. Transbaffle approaches were often necessary, and, provided that bidirectional CTI block was achieved at the index ablation, late recurrence was due to different arrhythmia mechanisms. Despite recurrence, ablation was associated with significant clinical improvement.