Background Accurate selection of patients who will benefit from a primary-prevention implantable cardioverter-defibrillator (ICD) remains a challenge. Cardiac magnetic resonance imaging (CMR) of myocardial tissue heterogeneity and EntropyXQT, a nonlinear electrocardiographic (ECG) measure of cardiac repolarization dynamics, predict ventricular tachyarrhythmias (VTs) and sudden cardiac arrest. Objectives Because CMR and EntropyXQT are fundamentally distinct structural and electrical measures, we hypothesized that they add major independent prognostic value to conventional clinical predictors of sudden cardiac arrest. Methods In 230 consecutive patients with a left ventricular ejection fraction ≤35% in sinus rhythm, baseline exposures before primary prevention ICD implantation included demographics, history, medications, laboratory results, conventional ECG indices of heart rate and QT variability, CMR myocardial tissue characterization, and EntropyXQT. The primary endpoint was ICD shock for VT, and secondary endpoints included all-cause events, including mortality. Results Over 6.1 ± 3.3 years of follow-up, 62 patients (27%) received appropriate ICD shocks. In multivariable analyses, EntropyXQT and CMR gray zone mass yielded adjusted hazard ratios (per SD change) of 1.8 (95% CI: 1.4-2.3) and 1.5 (95% CI: 1.2-1.8), respectively, and improved Harrell’s C-statistic from 0.59 to 0.73 in a model composed of conventional clinical predictors, left ventricular end-systolic volume (LVESV) and prescribed diuretics. EntropyXQT was the strongest predictor in years 1-3, whereas CMR and LVESV were stronger in years >3. Moreover, EntropyXQT independently predicted the secondary endpoints. Conclusions EntropyXQT and CMR gray zone mass complement each other and conventional risk factors, improving risk stratification for appropriate ICD shock and mortality, and together may enhance the selection of primary prevention ICD recipients. (Prospective Observational Study of the ICD in Sudden Cardiac Death Prevention (PROSe-ICD; NCT00733590)

BACKGROUND:Right ventricular (RV) apical pacing is associated with pacing induced cardiomyopathy. RV septal pacing has been proposed as a more physiological alternative, yet prior studies have yielded conflicting results. Cardiac computed tomography (CT) provides superior anatomical adjudication of lead position. We sought to evaluate whether CT-confirmed septal lead placement is associated with improved clinical outcomes compared with non-septal pacing. METHODS:We conducted a retrospective cohort study of 657 patients who underwent PPM implantation at the University of Pittsburgh Medical Center with subsequent chest CT imaging. The lead position was adjudicated as septal or non-septal. The primary outcome was a composite of heart failure hospitalization, atrial fibrillation admission, and/or all-cause mortality. Secondary outcomes included longitudinal changes in left ventricular ejection fraction (LVEF), and 12-month admission burden. RESULTS:Data from 657 patients were analyzed. Mean age was 73.9 ± 11.9 years, 50.5% were female, and mean baseline LVEF was 54.9 ± 7.1%. 150 had septal leads (22.8%), and 507 (77.2%) had non-septal leads. Over a median follow-up of 5.3 years (IQR 3.1-8.2), the composite endpoint occurred in 70.2% of patients, with incidence in the septal group (62.7%) and non-septal (72.4%, p = 0.21). In multivariable-adjusted multivariable adjusted models, septal versus non-septal pacing was not significantly associated with the composite outcome (HR = 1.00, 95% CI: 0.80-1.25, p = 0.996). LVEF declined in the non-septal group (54.0 ± 9.2% to 50.5 ± 11.4%, p < 0.001) but remained stable in the septal group (55.0 ± 6.6% to 54.9 ± 7.0%, p = 0.43). No significant differences were observed in the 12-month admission rates by lead position. CONCLUSIONS:Septal pacing was associated with preservation of left ventricular function compared to non-septal pacing, although this advantage did not translate to improved clinical outcomes. Septal pacing may help to reduce pacing-induced ventricular dysfunction when conduction system pacing is not feasible.

Atrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM) occurring in 20%-25% of patients and associated with significant morbidity including stroke risk and worsening heart failure. AF in HCM (HCM-AF) arises from disease-specific mechanisms distinct from non-HCM-AF, including HCM-related atrial structural changes (dilation/fibrosis), biophysical abnormalities (within ion-channels), and atrial dysfunction that culminate in an HCM-specific atrial myopathy. Although the adoption of contemporary AF therapies have been associated with improved clinical outcomes in non-HCM-AF populations, outcomes in HCM-AF remain worse, including lower rates of rhythm control success with catheter ablation and antiarrhythmic medications. In this context, we provide support that HCM-AF is a distinct clinical entity, highlighting gaps in knowledge and care, and represents an area of need for dedicated investigation as the effectiveness of applying therapeutics from AF populations without HCM to populations with HCM is unclear.

AIMS:Disopyramide and mavacamten both decrease left ventricular outflow tract gradients in obstructive hypertrophic cardiomyopathy (HCM). Yet, their effects on myocardial mechanics remain unclear. This study aimed to compare the effects of mavacamten and disopyramide on left ventricular mechanical dispersion (LVMD) and its association with life-threatening ventricular arrhythmias. METHODS AND RESULTS:Consecutive subjects (n = 120) with obstructive HCM treated with either Mavacamten or disopyramide from 2018 to 2024 were identified. Echocardiographic speckle-tracking strain imaging with myocardial work indices and LVMD quantification was performed at baseline and follow-up. Patients were followed up for life-threatening ventricular arrhythmias: sustained ventricular tachycardia (VT) or sudden cardiac arrest (SCA), up to 2 years. Propensity matching was performed for age and sex to compare the groups. Mavacamten significantly reduced LVMD (85.1 ± 26.4 ms vs. 64.3 ± 16.7 ms, P = 0.013) and global wasted work (GWW) (268 mmHg% (185-378) vs. 150 mmHg% (124-262), P = 0.006) and increased global work efficiency (GWE) (87% (82-92) vs. 90% (86-94), P = 0.038). None of the favourable effects were observed with disopyramide. The median follow-up duration was 12 (range 6-24) months. LVMD at follow-up was significantly associated with the outcome events [area under curve: 0.784, 95% CI (0.622-0.945), P < 0.001]. LVMD <72 ms at follow-up was associated with improved event-free survival (X6.4, log-rank P = 0.011). Mavacamten and global work indices were independent determinants of LVMD at follow-up. CONCLUSION:Mavacamten, but not disopyramide, decreased LVMD, GWW, and increased GWE in obstructive HCM. LVMD <72 ms at follow-up is promising for assessing the risk for life-threatening ventricular arrhythmias.

BACKGROUND:Sudden cardiac arrest (SCA), a leading cause of mortality, is administratively coded as ventricular tachycardia (VT), ventricular fibrillation (VF), or unspecified SCA. Diagnostic codes are widely used in research, yet their accuracy in reflecting true SCA events is uncertain. The objective of this study is to evaluate the relationship between administrative diagnostic code rank (listing order) and the likelihood of true SCA in patients presenting to the emergency department (ED). METHODS:From a database of 22 369 patients with VT/VF/SCA, we randomly selected 380 patients for detailed chart review. Diagnostic accuracy was confirmed when patients (1) had sustained a true VT/VF/SCA event during the index hospitalization and (2) when the event was not precipitated by non-cardiac causes. RESULTS:Manual chart review for the 380 patients (age 71 ± 12 years, 53% women) confirmed that 65% experienced true VT/VF/SCA and 55% had an arrest unrelated to non-cardiac causes. Diagnostic accuracy was 100% at priority rank #1 and declined significantly at lower ranks. In the overall larger cohort of 22 369 patients, recurrence of VT/VF/SCA trended 3% lower (p = 0.086) and all-cause mortality was 5% higher (p < 0.001) with each diagnostic priority rank decrease, over a mean follow-up of 1.5 years. CONCLUSION:Diagnostic codes show variable predictive accuracy for true VT/VF/SCA events, with the highest accuracy at priority rank #1. Higher-priority codes identify patients most likely to have true SCA, while lower-priority codes capture sick patients with other in-hospital events. These results have important implications for the interpretation of administrative health datasets.

AIM:The American College of Cardiology/American Heart Association Scientific Statement, "Clinical Considerations for the Care of the Tactical Athlete With Cardiovascular Abnormalities," was written to provide guidance and education for clinicians caring for the tactical athlete (ie, firefighters, law enforcement officers, military) with cardiovascular disease or risk for cardiovascular disease, and for the organizations overseeing the care and wellness of these athletes. The considerations are shaped by the interaction between occupational demands and fit for full duty assessments, including risk discussions about how a cardiovascular event in a tactical athlete could impact teammates' well-being, community safety, and overall mission success. METHODS:This scientific statement is organized into 11 sections focused on cardiovascular disease processes and other topics that are relevant when considering the potential risks and benefits of performing tasks specific to the tactical athlete. Task forces, comprised of experts in tactical athlete domains, sports cardiology, and the respective topics covered, were assigned to each section, and specific "Clinical Considerations Tables" for clinicians to reference were prepared. Comprehensive literature reviews and an emphasis on tactical athlete-focused data, as available, were integral in the writing of all clinical considerations presented. The framework mirrors that of the recently published, "Clinical Considerations for Competitive Sports Participation for Athletes With Cardiovascular Abnormalities: A Scientific Statement From the American Heart Association and American College of Cardiology." STRUCTURE:The specific sections in this document include: Section 1: Tactical Tasks Classification; Section 2: The Tactical Athlete Preparticipation Cardiac Evaluation; Section 3: Ethical and Legal Aspects of Tactical Clinical Management; Section 4: Genetic Cardiomyopathies; Section 5: Myocarditis and Other Acquired Cardiac Conditions; Section 6: Congenital Heart Disease; Section 7: Aortopathy, Bicuspid Aortic Valve, and Spontaneous Coronary Artery Dissection; Section 8: Syncope, SCA, Arrhythmias, and Devices; Section 9: Cardiac Channelopathies; Section 10: Older Tactical Athlete; Section 11: Environmental Exposures, PED/S, and Additional Cardiac Conditions and Considerations. Each section provides a summary detailing the rationale for key clinical considerations and the respective Clinical Considerations Table(s).

Diverse issues surrounding the unexpected arrhythmic sudden deaths (SDs) of young athletes have been studied intensely by cardiologists, internists, pediatricians, primary care and sports medicine physicians, and pathologists since 1980, with documentation of several cardiovascular causes, prominently including hypertrophic cardiomyopathy (HCM) (Figure 1).1 However, arguably no topic has generated more controversy than the standards governing decisions for eligibility vs disqualification of competitive student-athletes, given the understandable emotions generated by devastating, highly visible (often public) events paradoxically occurring in active young people representing the healthiest, most vigorous element of society. Even though associated with relative safety in statistical terms, that is, occurring at a low event rate of about 1:50,000 per competitors, these tragic events nevertheless periodically change our perceptions of sports participation.1-3 Therefore, this important issue remains unsettled within cardiovascular medicine with different opinions expressed in the literature.4-24 However, as experienced clinician-scientists, we take this opportunity to revisit that debate through the lens of subspecialty HCM clinical practice characterized by direct experience with the patient population.

Introduction:Diastolic dysfunction (DD) is often linked to the development and persistence of atrial fibrillation (AF), but its impact on healthcare resource utilization (HCRU) in patients with or without AF is unclear. Methods:Patients who received a transthoracic echocardiogram at our institution between 2010 and 2022 were included. DD was derived from the echocardiogram reports. HCRU included cardiac interventional, structural, surgical, and electrophysiology procedures, as well as diagnostic monitoring and imaging tests. Results:A cohort of 157,043 patients (mean age 58 ± 18 years, 55 % women, 88 % White, 9 % with AF, 23 % with DD, LVEF 56 ± 8 %, BMI 30 ± 8 kg/m2) was retrospectively analyzed. The presence and severity of DD is associated with a proportional increase in HCRU, calculated as the mean annual number of cardiac procedures per year. For patients with no AF, the HRCU was 0.60 ± 1.02 in patients with no DD versus 0.93 ± 1.39 in those with any grade of DD (p < 0.001). Similar findings were seen in patients with AF (HCRU 1.08 ± 1.40 vs. 1.27 ± 1.64, in patients without versus with DD, p < 0.001). At lower grades of DD, the presence of AF is associated with higher HCRU, but this difference dissipates in patients with grade III DD (1.77 ± 2.37 vs. 1.67 ± 2.15, p = 0.42). Discussion:DD is associated with higher HCRU in patients with or without AF. Conclusion:DD significantly increases HCRU which is higher in the presence of AF. These data emphasize the real-world impact of DD on HCRU and highlight the need to prioritize DD diagnosis and treatment to improve patients' health and reduce cost.

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Background: Wearable fitness trackers generate extensive physiological and activity data, offering potential to monitor health and predict outcomes. Machine learning (ML) techniques applied to these data may enable early identification of adverse health conditions, such as hospitalizations and development of cardiovascular diseases (CVD). This study aimed to evaluate ML models' ability to forecast the incidence of (1) hospitalizations from any cause and (2) of new diagnosis of CVD, including a composite of heart failure (HF), coronary artery disease or myocardial infarction (CAD-MI), cardiomyopathy (CMP), and atrial fibrillation (AF). Method and Results: Data from 14,157 participants in the All of Us study that included both Fitbit and electronic health record (EHR) information were censored on the date preceding events and analyzed using various ML classifiers for extracted feature data. Performance metrics included accuracy, area under the receiver operating characteristic (AUROC) curve, and F1 scores. Our overall study population was young (median age 54 years), with good representation of women (67%). For hospitalizations, a Random Forest classifier achieved the best performance (AUROC=0.95, accuracy=0.99, F1 score=0.92). For the CVD events, the best prediction model was gradient boosting (AUROC=0.80, accuracy=0.71, F1 score=0.15).Conclusion: ML models applied to Fitbit data demonstrate promise in predicting clinical outcomes with strong performance for predicting all-cause hospitalizations and modest performance for predicting incident CVD. Wearable technology could play a role in risk assessment and patient management.

Journal of Cardiovascular ElectrophysiologyEarly View INVITED EDITORIAL Concise guidelines on catheter ablation of atrial fibrillation from the European Cardiac Arrhythmias Society N. A. Mark Estes III, MD, Corresponding Author N. A. Mark Estes III, MD [email protected] orcid.org/0000-0002-5461-7247 The Heart and Vascular Institute, University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA Correspondence N. A. Mark Estes III, MD, The Heart and Vascular Institute, University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, 200 Lothrop St, Pittsburgh, PA 15213, USA. Email: [email protected]Search for more papers by this author N. A. Mark Estes III, MD, Corresponding Author N. A. Mark Estes III, MD [email protected] orcid.org/0000-0002-5461-7247 The Heart and Vascular Institute, University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA Correspondence N. A. Mark Estes III, MD, The Heart and Vascular Institute, University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, 200 Lothrop St, Pittsburgh, PA 15213, USA. Email: [email protected]Search for more papers by this author Simplicity is the Ultimate Sophistication-Leonardo de Vinci. First published: 18 April 2024 https://doi.org/10.1111/jce.16278 Disclosures: None. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. REFERENCES 1 Committee to Advise the Public Health Service on Clinical Practice Guidelines, Institute of Medicine. Introduction and background. In: MJ Field, KN Lohr, eds. Clinical Practice Guidelines: Directions of a New Program. National Academy Press; 1990; 19-33. Google Scholar 2Tricoci P. Scientific evidence underlying the ACC/AHA clinical practice guidelines. JAMA. 2009; 301: 831-841. 10.1001/jama.2009.205 CASPubMedWeb of Science®Google Scholar 3Roos M, Brodbeck J, Sarkozy A, Battista Chierchia G, DeAsmundis C, Brugada P. A critical analysis of the scientific evidence behind international guidelines related to cardiac arrhythmias. Circ: Arrhythm Electrophysiol. 2011; 4: 202-210. 10.1161/CIRCEP.110.958181 PubMedWeb of Science®Google Scholar 4Fanaroff AC, Califf RM, Windecker S, Smith SC, Lopes RD. Levels of evidence supporting American College of Cardiology/American Heart Association and European Society of Cardiology Guidelines, 2008-2018. JAMA. 2019; 321(11): 1069-1080. 10.1001/jama.2019.1122 PubMedWeb of Science®Google Scholar 5Calkins H, Hindricks G, Cappato R, et al. 2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation. 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BACKGROUND:Whether vigorous exercise increases risk of ventricular arrhythmias for individuals diagnosed and treated for congenital long QT syndrome (LQTS) remains unknown. METHODS:The National Institutes of Health-funded LIVE-LQTS study (Lifestyle and Exercise in the Long QT Syndrome) prospectively enrolled individuals 8 to 60 years of age with phenotypic and/or genotypic LQTS from 37 sites in 5 countries from May 2015 to February 2019. Participants (or parents) answered physical activity and clinical events surveys every 6 months for 3 years with follow-up completed in February 2022. Vigorous exercise was defined as >= 6 metabolic equivalents for >60 hours per year. A blinded Clinical Events Committee adjudicated the composite end point of sudden death, sudden cardiac arrest, ventricular arrhythmia treated by an implantable cardioverter defibrillator, and likely arrhythmic syncope. A National Death Index search ascertained vital status for those with incomplete follow-up. A noninferiority hypothesis (boundary of 1.5) between vigorous exercisers and others was tested with multivariable Cox regression analysis. RESULTS:Among the 1413 participants (13% <18 years of age, 35% 18-25 years of age, 67% female, 25% with implantable cardioverter defibrillators, 90% genotype positive, 49% with LQT1, 91% were treated with beta-blockers, left cardiac sympathetic denervation, and/or implantable cardioverter defibrillator), 52% participated in vigorous exercise (55% of these competitively). Thirty-seven individuals experienced the composite end point (including one sudden cardiac arrest and one sudden death in the nonvigorous group, one sudden cardiac arrest in the vigorous group) with overall event rates at 3 years of 2.6% in the vigorous and 2.7% in the nonvigorous exercise groups. The unadjusted hazard ratio for experience of events for the vigorous group compared with the nonvigorous group was 0.97 (90% CI, 0.57-1.67), with an adjusted hazard ratio of 1.17 (90% CI, 0.67-2.04). The upper 95% one-sided confidence level extended beyond the 1.5 boundary. Neither vigorous or nonvigorous exercise was found to be superior in any group or subgroup. CONCLUSIONS:Among individuals diagnosed with phenotypic and/or genotypic LQTS who were risk assessed and treated in experienced centers, LQTS-associated cardiac event rates were low and similar between those exercising vigorously and those not exercising vigorously. Consistent with the low event rate, CIs are wide, and noninferiority was not demonstrated. These data further inform shared decision-making discussions between patient and physician about exercise and competitive sports participation. REGISTRATION:URL: https://www.clinicaltrials.gov; Unique identifier: NCT02549664.

Background The long‐term impact of weight gain (WG) on cardiovascular outcomes among patients with atrial fibrillation (AF) is unclear. Methods and Results We studied 62 871 (mean age, 72±12, 43% women) adult patients with AF evaluated at the University of Pittsburgh Medical Center between January 1, 2010, and May 13, 2021. Serial body mass index, risk factors, comorbidities, and subsequent death and hospitalization were ascertained and stratified according to percentage WG (≥0% to <5%, ≥5% to <10%, and ≥10%). Over 4.9±3.19 years of follow‐up, 27 114 (43%) patients gained weight (61%, ≥0% to <5%; 23%, ≥5% to <10%; 16%, ≥10%). Patients with progressive WG were incrementally younger ( P <0.001) women (40%, 42%, and 47%) with lower median household income ( P =0.002) and active smoking (8%, 13% and 13%), and they were less likely to be on a non–vitamin K oral anticoagulant (39%, 37%, and 32%). WG was incrementally associated with a significant increase in risk of hospitalization for AF (≥10% WG; hazard ratio [HR], 1.2 [95% CI, 1.2–1.3]; P <0.0001), heart failure (≥10% WG; HR, 1.44 [95% CI, 1.3–1.6]; P <0.001; ≥5% to <10% WG; HR, 1.17 [95% CI, 1.1–1.2]; P <0.001), myocardial infarction (≥10% WG; HR, 1.2 [95% CI, 1.3–1.6]; P <0.001) and all‐cause stroke (4.2%, 4.3%, and 5.6%) despite significantly lower mean CHADS 2 Vasc score (2.9±1.7, 2.7±1.6, and 2.7±1.7). Patients with more WG were significantly more likely to receive cardiac and electrophysiologic interventions. Conclusions Among patients with AF, WG is incrementally associated with increased hospitalization for cardiovascular causes, particularly heart failure, stroke, myocardial infarction, and AF.