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Fnu Shailesh, Sandeep Singla, Ravi Sureddi, Abhishek J Deshmukh, Hakan Paydak Division of Cardiovascular Medicine, University of Arkansas for Medical Science, Little Rock, AR, USA Abstract: Mexiletine is a commonly used Class IB (Vaughan William classification) antiarrhythmic drug. We report a case of mexiletine-induced psychosis that was successfully managed by decreasing the dose and using alternative medications for management of ventricular tachycardia. Keywords: mexiletine, antiarrhythmic, psychosis

Background: It is unknown whether cardiac resynchronization therapy (CRT) would improve or halt the progression of heart failure (HF) in patients with mild to moderately reduced ejection fraction (HFmmrEF) and left bundle branch block (LBBB)., Objective: This study aimed to investigate the outcomes of CRT in patients with HFmmrEF and left ventricular conduction delay., Methods: A prospective, randomized clinical trial sponsored by the National Heart, Lung, and Blood Institute included 76 patients who met the study inclusion criteria (left ventricular ejection fraction [LVEF] of 36%-50% and LBBB). Patients received CRT-pacemaker and were randomized to CRT-OFF (right ventricular pacing 40 beats/min) or CRT-ON (biventricular pacing 60-150 beats/min). At a 6-month follow-up, pacing programming was changed to the opposite settings. New York Heart Association class, N-terminal pro-brain natriuretic peptide levels, and echocardiographic variables were collected at baseline, 6 months, and 12 months. The primary study end point was the left ventricular end-systolic volume (LVESV) change from baseline, and the primary randomized comparison was the comparison of 6-month to 12-month changes between randomized groups., Results: The mean age of the patients was 68.4 ± 9.8 years (male, 71%). Baseline characteristics were similar between the 2 randomized groups (all P > .05). In patients randomized to CRT-OFF first, then CRT-ON, LVESV was reduced from baseline only after CRT-ON (baseline, 116.1 ± 36.5 mL; CRT-ON, 87.6 ± 26.0 mL; P < .0001). The randomized analysis of LVEF showed a significantly better change from 6 to 12 months in the OFF-ON group (P = .003). LVEF was improved by CRT (baseline, 41.3% ±.7%; CRT-ON, 46.0% ± 8.0%; P = .002). In patients randomized to CRT-ON first, then CRT-OFF, LVESV was reduced after both CRT-ON and CRT-OFF (baseline, 109.8 ± 23.5 mL; CRT-ON, 91.7 ± 30.5 mL [P < .0001]; CRT-OFF, 99.3 ± 28.9 mL [P = .012]). However, the LVESV reduction effect became smaller between CRT-ON and CRT-OFF (P = .027). LVEF improved after both CRT-ON and CRT-OFF (baseline, 42.7% ± 4.3%; CRT-ON, 48.5% ± 8.6% [P < .001]; CRT-OFF, 45.9% ± 7.7% [P = .025])., Conclusion: CRT for patients with HFmmrEF significantly improves LVEF and ventricular remodeling after 6 months of CRT. The study provides novel evidence that early CRT benefits patients with HFmmrEF with LBBB., Competing Interests: Disclosures The authors have no conflicts of interest to disclose., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: The 2014 Heart Rhythm Society consensus statement defines histological (definite) and clinical (probable) diagnostic categories of cardiac sarcoidosis (CS), but few studies have compared their arrhythmic phenotypes and outcomes., Objective: The purpose of this study was to evaluate the electrophysiological/arrhythmic phenotype and outcomes of patients with definite and probable CS., Methods: We analyzed the arrhythmic/electrophysiological phenotype in a single-center North American cohort of 388 patients (median age 56 years; 39% female, n = 151) diagnosed with definite (n = 58) or probable (n = 330) CS (2000-2022). The primary composite outcome was survival to first ventricular tachycardia/fibrillation (VT/VF) event or sudden cardiac death. Key secondary outcomes were also assessed., Results: At index evaluation, in situ cardiac implantable electronic devices and antiarrhythmic drug use were more common in definite CS. At a median follow-up of 3.1 years, the primary outcome occurred in 22 patients with definite CS (38%) and 127 patients with probable CS (38%) (log-rank, P = .55). In multivariable analysis, only a higher ratio of the 18 F-fluorodeoxyglucose maximum standardized uptake value of the myocardium to the maximum standardized uptake value of the blood pool (hazard ratio 1.09; 95% confidence interval 1.03-1.15; P = .003, per 1 unit increase) was associated with the primary outcome. During follow-up, patients with definite CS had a higher burden of device-treated VT/VF events (mean 2.86 events per patient-year vs 1.56 events per patient-year) and a higher rate of progression to heart transplant/left ventricular assist device implantation but no difference in all-cause mortality compared with patients with probable CS., Conclusion: Patients with definite and probable CS had similarly high risks of first sustained VT/VF/sudden cardiac death and all-cause mortality, though patients with definite CS had a higher overall arrhythmia burden. Both CS diagnostic groups as defined by the 2014 Heart Rhythm Society criteria require an aggressive approach to prevent arrhythmic complications., Competing Interests: Disclosures No relevant disclosures by any of the authors., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Limited data exist on outcomes of atrial fibrillation (AF) catheter ablation based on hospital setting and, specifically, the availability of onsite cardiothoracic surgery (CTS). We aimed to describe the characteristics and outcomes of catheter ablation for AF performed at a facility with and without CTS., Methods: This was a retrospective study of consecutive patients who underwent catheter ablation for AF at hospital with (CTS) and without cardiothoracic surgery (N-CTS) from January 2011 through December 2019. Clinical and procedural characteristics, complications, and 1-year outcomes, including clinical events and AF recurrence, were collected., Results: There were 326 unique patients who underwent an index AF ablation procedure: 206 CTS patients and 120 N-CTS patients. There were no differences in overall cardiac complications (2.5% vs. 5.8%), including mapping catheter entrapment requiring open-heart surgery (0% vs. 0.5%), pericardial effusion requiring pericardiocentesis (0.8% vs. 0.5%), hemopericardium (1.7% vs. 0.5%), acute myocardial infarction (0% vs. 1.0%), and sinus node injury (0% versus 0.5%) (all P values > .05) between N-CTS and CTS patients. Likewise, overall noncardiac complications (20.7% vs. 19.8%, P = .85), including bleeding, cerebrovascular accident, and phrenic or vagus nerve injury, were similar between N-CTS and CTS hospitals. Also, 1-year cumulative Kaplan-Meier estimates of overall AF recurrence (11.6% vs. 16.4%; log-rank P = 0.21; HR 1.47; 95% CI, 0.79-2.74) were not statistically significant between N-CTS and CTS hospitals., Conclusion: Catheter ablation procedure is safe and effective regardless of onsite CTS presence, and there were no significant differences between the two hospital settings., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: The impact of mRNA-based coronavirus disease-2019 (COVID-19) vaccines on atrial arrhythmias (AA) and ventricular arrhythmias incidence is unknown., Methods: BIOTRONIK Home Monitoring data and Medicare Claims data were utilized to identify individuals implanted with a cardiac implantable electronic device (CIED) between 2010 and 2020 who received one or more doses of COVID-19 vaccine in 2021. The burden of AA (%) in the 3 months postvaccination was compared to those noted in the preceding 3 months using the Wilcoxon signed rank test. Sub-analyses comparing the effects of the influenza vaccine against the COVID-19 vaccine were also evaluated for individuals who received the influenza vaccine in 2020. A 1:1 propensity score match comparison between COVID-19 vaccine and non-vaccinated patients was also performed., Results: First and second doses of the COVID-19 vaccine were administered to 7757 and 6579 individuals with a CIED (age 76.2 ± 9.0 years, 49% males), respectively. While a small but statistically significant increase in the burden of AA was noted in the 3 months postvaccination compared to the preceding 3 months after the first dose of the COVID-19 vaccine (0.43 ± 9.04%, p = .028) a similar rise in AA was found following the influenza vaccine and for matched patients who did not receive the COVID-19 vaccine. No significant difference in device therapies was seen pre- and postvaccination., Conclusions: Though we report a small but significant increase in the number of CIED-detected AAs following vaccination for COVID-19 over a 3-month window, we believe these results correlate more with time and the progressive nature of AF rather than the vaccine itself. While these data should not dissuade from the use of these vaccines, increased vigilance and prompt treatment of AF is required for high-risk groups, specifically males over 70 years of age, following vaccination., (© 2024 Wiley Periodicals LLC.)

Background: Current guidelines present varying classes of recommendations for implantable cardioverter-defibrillator (ICD) utilization in patients with cardiac sarcoidosis (CS) and left ventricular ejection fraction (LVEF) <50%., Objective: The purpose of this study was to investigate the ventricular arrhythmia risk in CS patients with ICDs and varying degrees of left ventricular systolic dysfunction., Methods: The study included CS patients with an ICD and LVEF <50% at index evaluation. The primary outcome was survival free of sustained ventricular tachycardia (VT)/ventricular fibrillation (VF) after ICD implantation and was assessed comparatively for LVEF ≤35% vs 36%-49% and for primary vs secondary prevention ICD indication., Results: The study included 61 patients (median age 57 years; 61% male) with LVEF 36%-49% (n = 23) or LVEF ≤35% (n = 38). An ICD was implanted for secondary prevention in 24% and 44% of the LVEF ≤35% and 36%-49% groups, respectively (P = .11). The primary outcome did not differ between the 2 groups in univariable analysis (LVEF ≤35% vs 36%-49%: hazard ratio [HR] 0.85; 95% confidence interval [CI] 0.39-1.82; P = .67). In multivariable analysis, secondary prevention ICD indication was the only significant predictor of incident sustained VT/VF (HR 2.86; 95% CI 1.23-6.67; P = .015). Mean sustained VT/VF event burden was higher in the secondary compared with the primary prevention ICD patients (0.47 vs 0.11 events per patient-year; P = .005) but did not differ significantly between LVEF ≤35% and 36%-49% patients., Conclusion: CS patients with ICD indications and LVEF 36%-49% carry similarly high arrhythmic risk as those with LVEF ≤35%. Patients with secondary prevention ICDs have the highest overall risk., Competing Interests: Disclosures The authors have no conflicts to disclose., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Disclosures Drs Friedman, Attia, Kapa, and Siontis are coinventors of the artificial intelligence–enhanced electrocardiogram (AI-ECG) algorithms other than the one presented herein. Mayo Clinic has licensed such algorithms to Anumana Inc., with potential for commercialization. The AI-ECG algorithm for cardiac sarcoidosis detection has not been licensed to a commercial entity.

A 50-year-old woman presented with complete heart block on electrocardiogram. Echocardiogram revealed an intracardiac mass with extensive cardiac involvement. The patient was diagnosed with mantle cell lymphoma, confirmed via lymph node biopsy. Pacemaker implantation and chemotherapy were initiated, with subsequent improvement noted. This showcases an unusual manifestation of intracardiac metastasis with conduction system infiltration., Competing Interests: The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2024 The Authors.)

Background: Differentiating wide complex tachycardias (WCTs) into ventricular tachycardia (VT) and supraventricular wide tachycardia via 12-lead ECG interpretation is a crucial but difficult task. Automated algorithms show promise as alternatives to manual ECG interpretation, but direct comparison of their diagnostic performance has not been undertaken., Methods: Two electrophysiologists applied 3 manual WCT differentiation approaches (ie, Brugada, Vereckei aVR, and VT score). Simultaneously, computerized data from paired WCT and baseline ECGs were processed by 5 automated WCT differentiation algorithms (WCT Formula, WCT Formula II, VT Prediction Model, Solo Model, and Paired Model). The diagnostic performance of automated algorithms was compared with manual ECG interpretation approaches., Results: A total of 212 WCTs (111 VT and 101 supraventricular wide tachycardia) from 104 patients were analyzed. WCT Formula demonstrated superior accuracy (85.8%) and specificity (87.1%) compared with Brugada (75.2% and 57.4%, respectively) and Vereckei aVR (65.3% and 36.4%, respectively). WCT Formula II achieved higher accuracy (89.6%) and specificity (85.1%) against Brugada and Vereckei aVR. Performance metrics of the WCT Formula (accuracy 85.8%, sensitivity 84.7%, and specificity 87.1%) and WCT Formula II (accuracy 89.8%, sensitivity 89.6%, and specificity 85.1%) were similar to the VT score (accuracy 84.4%, sensitivity 93.8%, and specificity 74.2%). Paired Model was superior to Brugada in accuracy (89.6% versus 75.2%), specificity (97.0% versus 57.4%), and F1 score (0.89 versus 0.80). Paired Model surpassed Vereckei aVR in accuracy (89.6% versus 65.3%), specificity (97.0% versus 75.2%), and F1 score (0.89 versus 0.74). Paired Model demonstrated similar accuracy (89.6% versus 84.4%), inferior sensitivity (79.3% versus 93.8%), but superior specificity (97.0% versus 74.2%) to the VT score. Solo Model and VT Prediction Model accuracy (82.5% and 77.4%, respectively) was superior to the Vereckei aVR (65.3%) but similar to Brugada (75.2%) and the VT score (84.4%)., Conclusions: Automated WCT differentiation algorithms demonstrated favorable diagnostic performance compared with traditional manual ECG interpretation approaches., Competing Interests: Drs May, Kashou, and Desimone are obliged to disclose that they are “would-be” beneficiaries of intellectual property that relates to this manuscript’s content. The technology(s) discussed in this manuscript was disclosed Mayo Clinic Ventures or Office of Technology Management at Washington University in St. Louis. The other authors report no conflicts.

Introduction: Ventricular tachycardia storm or electrical storm (ES) is a common complication following left ventricular assist device (LVAD) implantation. The factors contributing to ES and outcomes are less studied. The study aimed to determine the factors associated with ES and the probability of survival in patients undergoing LVAD in three tertiary centers over a span of 15 years., Methods: We performed a retrospective cohort study on all patients who underwent LVAD implantation at the Mayo Clinic (Rochester, Phoenix, and Jacksonville) from January 1, 2006 to December 31, 2020. ES was defined as ≥3 episodes of sustained ventricular tachycardia over a period of 24 h with no identifiable reversible cause. Detailed chart reviews of the electronic health records within the Mayo Clinic and outside medical records were performed., Results: A total of 883 patients who underwent LVAD implantation were included in our study. ES occurred in 7% (n = 61) of patients with a median of 13 days (interquartile range [IQR]: 5-297 days) following surgery. We found 57% of patients (n = 35) developed ES within 30 days, while 43% (n = 26) patients developed ES at a median of 545  (IQR 152-1032) days after surgery. Following ES, 26% of patients died within 1 year. Patients with ES had a significant association with a history of ventricular arrhythmias and implantable cardioverter defibrillator (ICD) shocks before the procedure. ES was significantly associated with reduced survival compared to patients without ES (hazards ratio [HR]: 1.92, 95% CI: 1.39-2.64, p < .001)., Conclusion: Following LVAD implantation, the rate of ES was 7% with majority of ES occurring within 30 days of LVAD. Risk factors for ES included pre-implant history of ventricular arrhythmias and ICD shock. ES was significantly associated with reduced survival compared to patients without ES., (© 2024 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Background: We recently demonstrated that patients with atrial fibrillation (AF) and hypertrophic cardiomyopathy (HCM) have an increased risk of left atrial (LA) thrombus. In this study, we aimed to evaluate thrombus management, thrombus persistence, and thromboembolic events for HCM and non-HCM patients with AF and LA thrombus., Methods: From a cohort of 2,155 AF patients undergoing transesophageal echocardiography (TEE) for any indication, this study included 122 patients with LA thrombus (64 HCM patients and 58 non-HCM controls)., Results: There was no difference in mean CHA2DS2-VASc scores between HCM and control patients (3.9 ± 2.2 vs 3.8 ± 2.0, p = 0.88). Ten (16%) and 4 (7%) patients in the HCM and control groups, respectively, were in sinus rhythm at the time of TEE identifying the LA thrombus (p = 0.13). In all patients, the anticoagulation strategy was modified after the LA thrombus diagnosis. A total of 36 (56%) HCM patients and 34 (59%) control patients had follow-up TEE at median 90 and 62 days, respectively, after index TEE. The HCM group had significantly higher 90-day rates of persistent LA thrombus compared to the control group (88% vs 29%; p < 0.001). In adjusted models, HCM was independently associated with LA thrombus persistence. Among patients with LA thrombus, the 5-year cumulative incidence of thromboembolic events was 11% and 2% in HCM and control groups, respectively (p = 0.22)., Conclusions: Among patients with AF with LA thrombus identified by TEE, those with HCM appear to have a higher risk of LA thrombus persistence than non-HCM patients despite anticoagulation., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Many patients diagnosed with COVID-19 have persistent cardiovascular symptoms, but whether this represents a true cardiac process is unclear. This study assessed whether symptoms associated with long COVID among patients referred for cardiovascular evaluation are associated with objective abnormalities on cardiac testing to explain their clinical presentation., Methods: A retrospective cohort study of 40,462 unique patients diagnosed with COVID-19 at our tertiary referral was conducted and identified 363 patients with persistent cardiovascular symptoms a minimum of 4 weeks after polymerase chain reaction confirmed COVID-19 infection. Patients had no cardiovascular symptoms prior to COVID-19 infection. Each patient was referred for cardiovascular evaluation at a tertiary referral center. The incidence and etiology of abnormalities on cardiovascular testing among patients with long COVID symptoms are reported here. The cohort was subsequently divided into 3 categories based on the dominant circulating severe acute respiratory syndrome coronavirus 2 variant at the time of initial infection for further analysis., Results: Among 40,462 unique patients diagnosed with COVID-19 at our tertiary referral center from April 2020 to March 2022, 363 (0.9%) patients with long COVID were evaluated by Cardiology for possible cardiac sequelae from COVID and formed the main study cohort. Of these, 229 (63%) were vaccinated and 47 (12.9%) had severe initial infection, receiving inpatient treatment for COVID prior to developing long COVID symptoms. Symptoms were associated with a cardiac cause in 85 (23.4%), of which 52 (14.3%) were attributed to COVID; 39 (10.7%) with new cardiac disease from COVID, and 13 (3.6%) to worsening of pre-existing cardiac disease after COVID infection. The median troponin change in 45 patients with troponin measurements within 4 weeks of acute infection was +4 ng/dL (9 to 13 ng/dL). Among the total cohort with long COVID, 83.7% were diagnosed during the pre-Delta phase, 13.2% during the Delta phase, and 3.1% during the Omicron phase of the pandemic. There were 6 cases of myocarditis, 11 rhythm disorders, 8 cases of pericarditis, 5 suspected cases of endothelial dysfunction, and 33 cases of autonomic dysfunction., Conclusion: This pragmatic retrospective cohort study suggests that patients with long COVID referred for cardiovascular evaluation infrequently have new, objective cardiovascular disease to explain their clinical presentation. A multidisciplinary, patient-centered approach is warranted for symptom management along with conservative use of diagnostic testing., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Adults with congenital heart disease (ACHD) have increased risk of arrhythmias warranting implantation of cardiac implantable electronic devices (CIEDs), which may parallel the observed increase in survival of ACHD patients over the past few decades. We sought to characterize the trends and outcomes of CIED implantation in the inpatient ACHD population across US from 2005 to 2019., Methods: A retrospective analysis of the Nationwide Inpatient Sample (NIS) identified 1,599,519 unique inpatient ACHD admissions (stratified as simple (85.1%), moderate (11.5%), and complex (3.4%)) using the International Classification of Diseases 9/10-CM codes. Hospitalizations for CIED implantation (pacemaker, ICD, CRT-p/CRT-d) were identified and the trends analyzed using regression analysis (2-tailed p < 0.05 was considered significant)., Results: A significant decrease in the hospitalizations for CIED implantation across the study period [3.3 (2.9-3.8)% in 2005 vs 2.4 (2.1-2.6)% in 2019, p < 0.001] was observed across all types of devices and CHD severities. Pacemaker implantation increased with each age decade, whereas ICD implantation rates decreased over 70 years of age. Complex ACHD patients receiving CIED were younger with a lower prevalence of age-related comorbidities, however, had a greater prevalence of atrial/ventricular tachyarrhythmias and complete heart block. The observed inpatient mortality rate was 1.2%., Conclusions: In a nationwide analysis, we report a significant decline in CIED implantation between 2005 and 2019 in ACHD patients. This may either be due to a greater proportion of hospitalizations resulting from other complications of ACHD or reflect a declining need for CIED due to advances in medical/surgical therapies. Future prospective studies are needed to elucidate this trend further., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Cardiac implantable electronic devices (CIEDs), such as permanent pacemakers, implantable cardioverter-defibrillators, and cardiac resynchronization therapy devices, alleviate morbidity and mortality in various diseases. There is a paucity of real-world data on CIED complications and trends., Objectives: We sought to describe trends in noninfectious CIED complications over the past 3 decades in Olmsted County., Methods: The Rochester Epidemiology Project is a medical records linkage system comprising records of over 500,000 residents of Olmsted County from 1966 to present. CIED implantations between 1988 and 2018 were determined. Trends in noninfectious complications within 30 days of implantation were analyzed., Results: A total of 157 (6.2%) of 2536 patients who received CIED experienced device complications. A total of 2.7% of the implants had major complications requiring intervention. Lead dislodgement was the most common (2.8%), followed by hematoma (1.7%). Complications went up from 1988 to 2005, and then showed a downtrend until 2018, driven by a decline in hematomas in the last decade ( P < .01). Those with complications were more likely to have prosthetic valves. Obesity appeared to have a protective effect in a multivariate regression model. The mean Charlson comorbidity index has trended up over the 30 years., Conclusion: Our study describes a real-world trend of CIED complications over 3 decades. Lead dislodgements and hematomas were the most common complications. Complications have declined over the last decade due to safer practices and a better understanding of anticoagulant management., (© 2024 Heart Rhythm Society. Published by Elsevier Inc.)

Background: The incidence and prognosis of right bundle branch block (RBBB) following transcatheter aortic valve replacement (TAVR) are unknown. Hence, we sought to characterize the incidence of post-TAVR RBBB and determine associated risks of permanent pacemaker (PPM) implantation and mortality., Methods: All patients 18 years and above without preexisting RBBB or PPM who underwent TAVR at US Mayo Clinic sites and Mayo Clinic Health Systems from June 2010 to May 2021 were evaluated. Post-TAVR RBBB was defined as new-onset RBBB in the postimplantation period. The risks of PPM implantation (within 90 days) and mortality following TAVR were compared for patients with and without post-TAVR RBBB using Kaplan-Meier analysis and Cox proportional hazards modeling. The risks of PPM implantation (within 90 days) and mortality following TAVR were compared for patients with and without post-TAVR RBBB using Kaplan-Meier analysis and Cox proportional hazards modeling., Results: Of 1992 patients, 15 (0.75%) experienced new RBBB post-TAVR. There was a higher degree of valve oversizing among patients with new RBBB post-TAVR versus those without (17.9% versus 10.0%; P =0.034). Ten patients (66.7%) with post-TAVR RBBB experienced high-grade atrioventricular block and underwent PPM implantation (median 1 day; Q1, 0.2 and Q3, 4), compared with 268/1977 (13.6%) without RBBB. Following propensity score adjustment for covariates (age, sex, balloon-expandable valve, annulus diameter, and valve oversizing), post-TAVR RBBB was significantly associated with PPM implantation (hazard ratio, 8.36 [95% CI, 4.19-16.7]; P <0.001). No statistically significant increase in mortality was seen with post-TAVR RBBB (hazard ratio, 0.83 [95% CI, 0.33-2.11]; P =0.69), adjusting for age and sex., Conclusions: Although infrequent, post-TAVR RBBB was associated with elevated PPM implantation risk. The mechanisms for its development and its clinical prognosis require further study., Competing Interests: Disclosures None.

Background: The outcomes of left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) in patients with heart failure remain to be learned., Objective: The objective of this study was to assess the echocardiographic and clinical outcomes of LBBP, LVSP, and deep septal pacing (DSP)., Methods: This retrospective study included patients who met the criteria for cardiac resynchronization therapy (CRT) and underwent attempted LBBP in 5 Mayo centers. Clinical, electrocardiographic, and echocardiographic data were collected at baseline and follow-up., Results: A total of 91 consecutive patients were included in the study. A total of 52 patients had LBBP, 25 had LVSP, and 14 had DSP. The median follow-up duration was 307 (interquartile range 208, 508) days. There was significant left ventricular ejection fraction (LVEF) improvement in the LBBP and LVSP groups (from 35.9 ± 8.5% to 46.9 ± 10.0%, P < .001 in the LBBP group; from 33.1 ± 7.5% to 41.8 ± 10.8%, P < .001 in the LVSP group) but not in the DSP group. A unipolar paced right bundle branch block morphology during the procedure in lead V1 was associated with higher odds of CRT response. There was no significant difference in heart failure hospitalization and all-cause deaths between the LBBP and LVSP groups. The rate of heart failure hospitalization and all-cause deaths were increased in the DSP group compared with the LBBP group (hazard ratio 5.10, 95% confidence interval 1.14-22.78, P = .033; and hazard ratio 7.83, 95% confidence interval 1.38-44.32, P = .020, respectively)., Conclusion: In patients undergoing CRT, LVSP had comparable CRT outcomes compared with LBBP., (© 2024 Heart Rhythm Society. Published by Elsevier Inc.)

Competing Interests: Declaration of Competing Interest The authors have no competing interests to declare.

Introduction: Bone loss is present in all revision total knee arthroplasties. Metaphyseal cones allow surgeons to negotiate loss of femoral and tibial bone stock while obtaining stable bony fixation. This study examines the mid-term functional and radiographic outcomes in patients undergoing revision total knee arthroplasty (rTKA) utilizing a novel metaphyseal cone system., Methods: This multicenter retrospective study examined all patients who received a porous, titanium tibial or femoral cone at four academic urban tertiary care institutions and presented for a minimum two-year follow-up. Patient demographics, indications for revision surgery, knee range-of-motion (ROM), re-revision rates, radiographic measurements, bone defect per AORI classification, and implant osseointegration were evaluated according to the Knee Society total knee arthroplasty (TKA) radiographic evaluation system., Results: One-hundred and four patients received 128 cone implants (84 tibial, 44 femoral cones; 24 patients with simultaneous ipsilateral tibial and femoral cones; 104 rTKA) with mean follow-up of 32.75 ± 6.54 months. The pre-operative main revision indications were aseptic loosening 36 (34.61 %), periprosthetic infection (PJI) 23 (22.11 %) and instability 18 (17.3 %). Thirteen rTKA underwent re-revision surgery: 3 for acute PJI, 4 for chronic PJI, 5 for instability, and 1 for mechanical failure of a hinged system. At most recent radiographic follow-up available, all unrevised cones had evidence of osteointegration and no visible implant migration.All-cause re-operation free survivorship was 87.5 % (91/104), and all-cause cone implant survivorship was 96.09 % (123/128 cones) at 2-year follow-up., Conclusion: This study demonstrates excellent mid-term outcomes of a novel porous, titanium metaphyseal cone in patients with large bone defects undergoing complex revision TKA., Level of Evidence: IV, case series., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Ran Schwarzkopf, MD, MSc reports financial support was provided by 10.13039/100009026Smith and Nephew Inc. Ran Schwarzkopf reports a relationship with American Association of Hip and Knee Surgeons that includes: board membership. Jose A. Rodriguez reports a relationship with American Association of Hip and Knee Surgeons that includes: board membership. Ran Schwarzkopf reports a relationship with American Academy of Orthopaedic Surgeons that includes: board membership. Jose A. Rodriguez reports a relationship with American Academy of Orthopaedic Surgeons that includes: board membership. Jose A. Rodriguez reports a relationship with Eastern Orthopaedic Association that includes: board membership. Ran Schwarzkopf reports a relationship with Smith and Nephew Inc that includes: consulting or advisory. Jose A. Rodriguez reports a relationship with Smith and Nephew Inc that includes: consulting or advisory. Jose A. Rodriguez reports a relationship with ConforMIS Inc that includes: consulting or advisory. Jose A. Rodriguez reports a relationship with DePuy Orthopaedics Inc that includes: consulting or advisory. Jose A. Rodriguez reports a relationship with Medacta USA INC that includes: consulting or advisory. Jose A. Rodriguez reports a relationship with Exactech Inc that includes: consulting or advisory. William B. Lutes reports a relationship with Smith and Nephew Inc that includes: consulting or advisory. William B. Lutes reports a relationship with Orthoalign that includes: consulting or advisory. Ran Schwarzkopf reports a relationship with Intelijoint that includes: equity or stocks. Ran Schwarzkopf reports a relationship with Gauss Surgical that includes: equity or stocks. Gijs van Hellemondt reports a relationship with Zimmer Biomet Holdings Inc that includes: consulting or advisory. Gijs van Hellemondt reports a relationship with Smith and Nephew Inc that includes: consulting or advisory., (© 2023 Delhi Orthopedic Association. All rights reserved.)

The discrimination of ventricular tachycardia (VT) versus supraventricular wide complex tachycardia (SWCT) via 12-lead electrocardiogram (ECG) is crucial for achieving appropriate, high-quality, and cost-effective care in patients presenting with wide QRS complex tachycardia (WCT). Decades of rigorous research have brought forth an expanding arsenal of applicable manual algorithm methods for differentiating WCTs. However, these algorithms are limited by their heavy reliance on the ECG interpreter for their proper execution. Herein, we introduce the Mayo Clinic ventricular tachycardia calculator (MC-VTcalc) as a novel generalizable, accurate, and easy-to-use means to estimate VT probability independent of ECG interpreter competency. The MC-VTcalc, through the use of web-based and mobile device platforms, only requires the entry of computerized measurements (i.e., QRS duration, QRS axis, and T-wave axis) that are routinely displayed on standard 12-lead ECG recordings., (© 2023 The Authors. Annals of Noninvasive Electrocardiology published by Wiley Periodicals LLC.)

Background: Adults with repaired tetralogy of Fallot (TOF) have right atrial (RA) remodeling and dysfunction, and RA function can be measured using speckle tracking echocardiography. There are limited data about the role of RA strain imaging for risk stratification in this population. We hypothesized that RA reservoir strain can identify TOF patients at risk of developing atrial arrhythmia. To test this hypothesis, we assessed the relationship between RA reservoir strain and atrial arrhythmias in adults with repaired TOF., Method: Retrospective cohort study of adults with repaired TOF, and no prior history of atrial arrhythmias. Atrial arrhythmia was defined as atrial fibrillation, atrial flutter/atrial tachycardia, and categorized as new-onset versus recurrent atrial arrhythmias., Results: We identified 426 patients (age 33 ± 12 years; males 208 (49%)) that met the inclusion criteria. The mean RA reservoir strain, conduit strain, and booster strain were 34 ± 11%, 20 ± 9%, and 15 ± 12%, respectively. Of 426 patients, 73 (17%) developed new-onset atrial arrhythmias (atrial flutter/tachycardia n = 42; atrial fibrillation n = 31); annual incidence 1.9%. RA reservoir strain was associated with new-onset atrial arrhythmias (adjusted HR 0.95, 95% CI 0.93-0.97) after multivariable adjustment. Of 73 patients with new-onset atrial arrhythmia, 41 (56%) had recurrent atrial arrhythmia (atrial flutter/tachycardia n = 18; atrial fibrillation n = 23); annual incidence 11.2%. Similarly, RA reservoir strain was associated with recurrent atrial arrhythmias (adjusted HR 0.92, 95% CI 0.88-0.96) after multivariable adjustment., Conclusions: RA strain indices can identify patients at risk for atrial arrhythmias, and this can in turn, be used to guide the type/intensity of therapy in such patients., Competing Interests: Disclosures The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Atrial fibrillation (AF) is common in hypertrophic cardiomyopathy (HCM). There is limited data regarding the outcomes of AF catheter ablation in HCM patients. In this study, we aimed to synthesize all available evidence on the effectiveness of ablation of AF in patients with HCM compared to those without HCM., Methods and Results: We systematically reviewed bibliographic databases to identify studies published through February 2023. We included cohort studies with available quantitative information on rates of recurrent atrial arrhythmias, anti-arrhythmic drug (AAD) therapy, and repeat ablation procedures after initial AF ablation in patients with vs without HCM. Estimates were combined using random-effects meta-analysis models and reported as risk ratios (RR) and 95% confidence intervals (CI). Eight studies were included in quantitative synthesis (262 HCM and 642 non-HCM patients). During median follow-up 13-54 months across studies, AF recurrence rates ranged from 13.3% to 92.9% in HCM and 7.6% to 58.8% in non-HCM patients. The pooled RR for recurrent atrial arrhythmia after the first AF ablation in HCM patients compared to non-HCM controls was 1.498 (95% CI = 1.305-1.720; P < 0.001). During follow-up, HCM patients more often required AAD therapy (RR = 2.844; 95% CI = 1.713-4.856; P < 0.001) and repeat AF ablation (RR = 1.544; 95% CI = 1.070-2.228; P = 0.02). The pooled RR for recurrent atrial arrhythmias after the last AF ablation was higher in patients with HCM than those without HCM (RR = 1.607; 95% CI = 1.235-2.090; P < 0.001)., Conclusions: Compared to non-HCM patients, those with HCM had higher rates of recurrent atrial arrhythmias, AAD use, and need for repeat AF ablation after initial ablation of AF., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

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., Competing Interests: Disclosures Dr Madhavan receives research funding from Boston Scientific, BMS/Pfizer, and Convatec, Inc; speaker honorarium from Biosense Webster; and she is on the steering committee of CERTITUDE Registry, Biotronik, Inc. Dr Asirvatham receives speaking/honoraria from Abbott, Biosense Webster, Biotronik, Boston Scientific, Medtronic, and Zoll. All other authors have no conflicts to disclose.

Background: Magnetic resonance imaging (MRI) safety in patients with an epicardial cardiac implantable electronic device (CIED) is uncertain., Objective: The purpose of this study was to assess the safety and adverse effects of MRI in patients who had surgically implanted epicardial CIED., Methods: Patients with surgically implanted CIEDs who underwent MRI with an appropriate cardiology-radiology collaborative protocol between January 2008 and January 2021 were prospectively studied in 2 clinical centers. All patients underwent close cardiac monitoring through MRI procedures. Outcomes were compared between the epicardial CIED group and the matched non-MRI-conditional transvenous CIED group., Results: Twenty-nine consecutive patients with epicardial CIED (41.4% male; mean age 43 years) underwent 52 MRIs in 57 anatomic regions. Sixteen patients had a pacemaker, 9 had a cardiac defibrillator or cardiac resynchronization therapy-defibrillator, and 4 had no device generator. No significant adverse events occurred in the epicardial or transvenous CIED groups. Battery life, pacing, sensing thresholds, lead impedance, and cardiac biomarkers were not significantly changed, except 1 patient had a transient decrease in atrial lead sensing function., Conclusion: MRI of CIEDs with epicardially implanted leads does not represent a greater risk than transvenous CIEDs when performed with a multidisciplinary collaborative protocol centered on patient safety., (Copyright © 2023. Published by Elsevier Inc.)

Background: Recognition of the causes of early mortality after ventricular tachycardia (VT) ablation in patients with reduced left ventricular ejection fraction (LVEF) is an essential step toward improving postprocedural outcomes., Objectives: This study sought to determine the causes of early mortality (≤30 days) after VT ablation in patients with reduced LVEF and to understand further the circumstances surrounding death after the procedure., Methods: We performed a retrospective analysis of all patients undergoing VT ablation in patients with reduced LVEF from January 1, 2013, to November 10, 2021, at the Mayo Clinic (Rochester, Phoenix, and Jacksonville). Causes of death were identified through a detailed chart review of the electronic health record within the Mayo Clinic system and outside records., Results: A total of 503 patients (mean age 63 ± 13 years, 11.2% women) with ejection fraction <50% were included in the study. The 30-day all-cause mortality rate was 5.0% (n = 25), and the mortality rate due to a procedural complication was 0.4%. Among all 30-day deaths, recurrent VT was the most common primary cause of death (44.0%). This was followed by decompensated heart failure (28.0%), procedure-related death (8.0%), cerebrovascular accident (4.0%), and infection (4.0%). Most patients (91.0%) who died from VT had VT recurrence within 3 days of the ablation. The average PAINESD score among early mortality was 20 ± 4, and 92.0% of these patients (n = 23) had a score >15. Significant predictors of early mortality included nonischemic cardiomyopathy, lower LVEF, electrical storm, and ventricular fibrillation., Conclusions: The overall early mortality (≤30 days) rate after catheter ablation of VT in patients with reduced LVEF was 5.0%, but the death rate directly due to a procedural complication was only 0.4%. The most common cause of death was recurrent VT, followed by heart failure. Further research into ablation strategies is vital to improving the safety, efficacy, and durability of VT ablation., Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023. Published by Elsevier Inc.)

A patient presented with symptoms of palpitations. Her standard 12-lead electrocardiogram captured 3 potential causes of her symptoms (premature atrial contractions, junctional rhythm, and narrow complex tachycardia). Further workup uncovered dual atrioventricular node physiology with 1:2 sinus conduction and resultant alternating QRS from a slow and fast conduction pathway. ( Level of Difficulty: Intermediate. )., Competing Interests: Dr Deshmukh has served as a consultant for GE Healthcare. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2023 The Authors.)

Competing Interests: Disclosures None.

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., Competing Interests: Disclosures None.

Intrinsic antitachycardia pacing (iATP) is a novel, automated antitachycardia pacing (ATP) algorithm that provides individualized therapy to terminate ventricular tachycardia (VT). If the first ATP attempt is unsuccessful, the algorithm analyzes the tachycardia cycle length and the postpacing interval and adjusts the subsequent sequence to successfully terminate VT. This algorithm was effective in a single clinical study without a comparator arm. However, iATP failure has not been well-documented in the literature. This publication represents the first case series with episode analysis of iATP failure, including a demonstration of its proarrhythmic effect., Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Background: Although patients with coarctation of aorta (COA) have clinical risk factors for atrial fibrillation (AF), there are limited data about AF prevalence, and role of left atrial (LA) indices for risk stratification in this population. We hypothesized that LA indices (LA reservoir strain and LA volume index) were associated with AF, and would identify patients at risk for AF progression., Methods: We analyzed electrocardiograms/Holters, and echocardiograms of adult COA patients at Mayo Clinic (2000-2018)., Results: Of 776 patients, 726(94 %), 46(5.9 %) and 4(0.5 %) had no history of AF, paroxysmal AF, and persistent AF respectively; yielding AF prevalence of 6.4 %. LA reservoir strain (AUC 0.782 [0.751-0.808]) had more robust association with AF as compared to LA volume index (AUC difference -0.115, p < 0.001).Among 726 patients without prior AF, 25(3.4 %) had new-onset AF during follow-up. LA reservoir strain <25 % and LA volume index >34 ml/m 2 were independent predictors of new-onset AF (HR 1.81 [1.15-3.85], and HR 1.41 [1.03-4.78], respectively). Of 46 patients with paroxysmal AF, 22(48 %) had recurrent AF, and LA reservoir strain <25 % was an independent predictor of recurrent AF (HR 1.94 [1.41-4.17]). LV pressure overload and stiffness indices were associated with progressive LA dysfunction and new-onset AF., Conclusions: Collectively, these data suggest that LA strain can potentially be used for AF risk stratification. Further studies are required to determine whether LA strain can proactively identify patients that will respond favorably to different antiarrhythmic therapies, and whether interventions to reduce LV pressure overload will improve LA function and reduce AF progression., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Introduction: A current limitation of single chamber implantable cardioverter defibrillators (ICDs) is the lack of an atrial lead to reliably detect atrial fibrillation (AF) episodes. A novel ventricular based atrial fibrillation (VBAF) detection algorithm was created for single chamber ICDs to assess R-R variability for detection of AF., Methods: Patients implanted with Visia AF™ ICDs were prospectively enrolled in the Medtronic Product Surveillance Registry from December 15, 2015 to January 23, 2019 and followed with at least 30 days of monitoring with the algorithm. Time to device-detected daily burden of AF ≥ 6 min, ≥6 h, and ≥23 h were reported. Clinical actions after device-detected AF were recorded., Results: A total of 291 patients were enrolled with a mean follow-up of 22.5 ± 7.9 months. Of these, 212 (73%) had no prior history of AF at device implant. However, 38% of these individuals had AF detected with the VBAF algorithm with daily burden of ≥6 min within two years of implant. In these 80 patients with newly detected AF by their ICD, 23 (29%) had a confirmed clinical diagnosis of AF by their provider. Of patients with a clinical diagnosis of AF, nine (39%) were newly placed on anticoagulation, including five of five (100%) patients having a burden >23 h., Conclusions: Continuous AF monitoring with the new VBAF algorithm permits early identification and actionable treatment for patients with undiagnosed AF that may improve patient outcomes., (© 2022 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)