The American Journal of Cardiology

Background: Anatomic isthmus 3 (AI 3) is defined as the myocardium between the pulmonary valve annulus and the ventricular septal defect patch that persists after tetralogy of Fallot (ToF) repair. Ventricular tachycardia (VT) propagated through slow conducting AI 3 (SCAI 3) represents a significant cause of morbidity in ToF. There is an unmet need for non-invasive identification of SCAI 3 in patients with ToF. Objectives: To assess whether the anatomic features of AI 3 as derived from cardiac computed tomography (CT) can predict slow conduction velocity during EP study. Methods: This retrospective single-center study included patients with ToF who underwent an electrophysiologic study and had AI 3 width measured from the pre-procedure cardiac CT. All patients underwent programmed ventricular stimulation, and electroanatomic. Logistic regression was performed to assess the relationship between AI 3 width and the presence of SCAI 3. Results: Of 27 consecutive patients with ToF, twelve patients were found to have SCAI 3, and ten patients were found to have SCAI 3 mediated VT. The AI 3 was significantly narrower in patients with SCAI 3 compared to those with normal AI 3 conduction (18.4 +/- 6.6 mm vs. 29.2 +/- 9.0 mm; p = 0.001). An AI 3 width above 21.5 mm carried a negative predictive value of 80.0%. Conclusion: In adults with repaired ToF referred for electrophysiology study, a narrower CT-derived AI 3 width was associated with SCAI 3 identification. AI 3 width measured on a CT obtained before PV replacement could help guide invasive risk stratification.

Background Although atrial fibrillation (AF) frequently coexists with degenerative mitral regurgitation (DMR), imaging assessment of left atrial (LA) fibrosis in this population remains limited. We integrated echocardiographic and cardiac magnetic resonance (CMR) late gadolinium enhancement (LGE) parameters to characterize LA remodeling features in isolated DMR and assess its association with AF. Methods In this retrospective study, consecutive patients with moderate-to-severe or severe isolated DMR who underwent echocardiography and CMR, including cine and LGE sequences, between February 2025 and January 2026 were included. Patients with other left-sided valvular disease of mild or greater severity or cardiomyopathy were excluded to isolate a population of "pure" DMR patients, and LALGE percentage was calculated as LALGE area divided by left atrial wall area. Imaging parameters were compared according to AF status and evaluated using logistic regression and receiver operating characteristic (ROC) analysis. Multimodality models were constructed to assess the combined discriminative value of echocardiographic and CMR parameters. Results Among 46 patients with DM (71.7% male, 62.0 years of age), 17 (37.0%) had AF. Compared with patients without AF, AF patients were older (P=0.005) and had lower LA reservoir strain [LASr; adjusted odds ratio (OR) 0.86; 95% confidence interval (CI) 0.76-0.94; P<0.001], higher left atrioventricular coupling index (LACI; adjusted OR per 10-percentage-point increase, 1.48; 95% CI, 1.18-2.23; P<0.001), larger LALGE area (adjusted OR 1.20; 95% CI, 1.07-1.41; P<0.001), higher LALGE percentage (adjusted OR 1.19; 95% CI, 1.02-1.42; P=0.025). Among single parameters, LACI showed the highest area under the curve (AUC 0.85, 95% CI 0.72-0.99; cutoff 58.59%), whereas LALGE area showed an AUC of 0.78 (95% CI 0.61-0.94; cutoff 13.73 cm2). Among all models, LASr combined with LALGE percentage achieved the highest AUC (0.91, 95% CI 0.80-1.00), with sensitivity 76.5%, specificity 96.6%, positive predictive value 92.9%, and negative predictive value 87.5%. In serum biomarker analysis, patients with AF had significantly higher levels of C-terminal telopeptide of type I collagen (CITP) than those without AF (P=0.009). Follow-up data were available for 45 patients (97.8%), with a median follow-up duration of 9.2 months (IQR, 7.7-12.2 months). Conclusions In patients with DMR, AF was associated with more advanced LA structural remodeling, impaired LA function, and higher CMR LGE burden. Echocardiographic LA functional parameters, when combined with LALGE measures, may provide complementary information for the discrimination of AF. Given the exploratory nature of this study, the findings require external validation.

Background Real-world data regarding mavacamten use in underserved and racially diverse populations remain limited, particularly for long-term therapy implementation. Structural barriers such as financial instability, fragmented healthcare access, and challenges adhering to REMS-related monitoring requirements may affect longitudinal therapy implementation. Methods We performed a retrospective observational study of consecutive patients with symptomatic obstructive hypertrophic cardiomyopathy (oHCM) evaluated for mavacamten therapy at a tertiary HCM center in Bronx, NY, between 6/2022-10/2025. Patients were followed for up to 48 weeks after treatment initiation. Clinical characteristics, treatment interruptions, adverse events, echocardiographic and functional outcomes, and implementation barriers were assessed descriptively. Results Seventy-two patients with symptomatic oHCM were evaluated for mavacamten; sixty-seven initiated treatment. Mean age was 66.9{+/-}15.3 years, 72% were female, and 61% identified as Black or Hispanic. Median resting left ventricular outflow tract (LVOT) gradient decreased from 51mmHg (IQR30-88) at baseline to 7mmHg (IQR5-10) at 48 weeks. Median Valsalva LVOT gradient decreased from 74mmHg (IQR50-104) to 20mmHg (IQR10-29). At final follow-up, 80% of patients improved by [&ge;]1 NYHA functional class. LVEF declined below 50% in five patients and recovered in all cases. Approximately one-quarter experienced treatment interruption or discontinuation, nearly half related to insurance instability, non-adherence, and REMS-related monitoring barriers. Conclusions Mavacamten demonstrated efficacy and safety outcomes comparable to those reported in clinical trials and prior registries in this predominantly underserved minority urban cohort. However, structural and healthcare-access barriers substantially affected long-term treatment implementation. These findings highlight the need to address healthcare-system barriers to ensure equitable implementation of contemporary HCM therapies.

Background Pulsed-field ablation (PFA) has recently been approved in the USA as a new method for treating atrial fibrillation (AF). PFA provides a promising new approach in the treatment of atrial fibrillation (AF), which historically has a high recurrence rate post-ablation. Of significance, PFA has shown promising data in terms of safety and procedural efficiency to radiofrequency ablation (RFA). Objective The purpose of this study was to compare the procedural and health outcomes in patients with recurrent AF undergoing ablation using PFA or RFA. Methods Consecutive patients with a history of previous radiofrequency ablation and recurrent AF undergoing redo ablation with PFA or RFA were included. Patients were seen for follow-up in the clinic ranging from 4 months to a year and we reported ablation strategy and arrhythmia type. The primary outcome was recurrence of any atrial arrhythmia after a 90-day blanking period. Results A total of 242 patients with recurrent AF underwent redo ablation using PFA (n = 54, 22.5%) or RFA (n = 188, 77.5%). The PFA cohort was younger on average (66 vs. 70 years) with a lower mean CHA2DS2-VASc score (2.2 vs. 3.06, p=0.001) compared to the RFA cohort. PFA procedures were shorter (162{+/-}53 vs 206{+/-}60 minutes, p<0.001) but required more fluoroscopy (13.9{+/-}8.9 vs 8.7{+/-}6.3 minutes, p<0.001). Among patients seen on follow-up, recurrence occurred in 28% of PFA versus 55% of RFA patients, with longer arrhythmia-free survival after PFA (log-rank p=0.03). PFA remained associated with lower recurrence after multivariable adjustment (HR 0.4, 95% CI 0.2?0.9, p=0.04). Adverse events, predominantly vascular access?related, were similar. Conclusion Among patients with recurrent atrial arrhythmias after prior RFA, repeat PFA was associated with shorter procedures, greater fluoroscopy use, and lower arrhythmia recurrence, with comparable safety.

Background Exercise intolerance is common in adults with repaired tetralogy of Fallot (rTOF) despite preserved left ventricular ejection fraction (LVEF [&ge;]50%). Whether reduced exercise capacity is associated with early cardiac remodeling remains unclear. Objectives To determine whether reduced exercise capacity in rTOF with preserved LVEF is associated with diastolic dysfunction, atrial remodeling, right ventricular (RV) dysfunction, and myocardial fibrosis. Methods We retrospectively studied adults with rTOF and preserved LVEF who underwent cardiopulmonary exercise testing (CPET) and transthoracic echocardiography (TTE) and/or cardiac MRI (CMR) within 18 months. Exercise capacity was assessed by percent-predicted peak VO2 (ppVO2). Diastolic function and atrial remodeling were evaluated by TTE, and CMR assessed RV function and myocardial fibrosis. Results Reduced exercise capacity was associated with larger left atrial volume index (LAVI; p < 0.001), elevated E/e' and reduced e' velocity (both p < 0.05), and reduced RV systolic function (p < 0.001). LAVI correlated inversely with ppVO2 ({rho} = -0.27, p = 0.003). A composite diastolic dysfunction score showed a graded relationship with exercise capacity, with patients exhibiting [&ge;]2 abnormalities having lower ppVO2 than those with [&le;]1 abnormality (both p < 0.01). In contrast, pulmonary regurgitation (PR) severity and myocardial fibrosis by late gadolinium enhancement (LGE) were not associated with exercise capacity. Conclusions In adults with rTOF and preserved LVEF, reduced exercise capacity is associated with atrial remodeling, diastolic dysfunction, and RV dysfunction despite the absence of overt myocardial fibrosis. This suggests that multimodal imaging identifies an imaging-defined cardiac remodeling phenotype associated with early functional impairment.

Background Adults with a systemic right ventricle (sRV) due to congenitally corrected transposition of the great arteries (ccTGA) or atrial switch repair for d-transposition of the great arteries (d-TGA) experience substantial physiologic and psychosocial morbidity. Relationships among exercise capacity, sRV function, and mental health remain incompletely characterized. Objectives To characterize relationships among anatomic subtype, exercise capacity, sRV function, and mental health in adults with sRV physiology. Methods We performed a retrospective cohort study of adults with ccTGA or d-TGA (Mustard/Senning) followed at a tertiary Adult Congenital Heart Disease program from 2000 to 2025. Clinical, imaging, cardiopulmonary exercise testing, and patient-reported data were obtained from electronic health records. Mental health diagnoses were identified from clinical documentation. Functional status was assessed using NYHA class and the Kansas City Cardiomyopathy Questionnaire (KCCQ-12). Results Among 137 adults (ccTGA, n = 51; d-TGA, n = 86), percent-predicted peak VO2 was lower in d-TGA than ccTGA (60% vs 74%, p < 0.001), as was sRV systolic function (41 +/- 11% vs 47 +/- 10%, p < 0.01). Anxiety or depression was more common in d-TGA (46% vs 25%, p < 0.05). Across the cohort, anxiety or depression was associated with lower exercise capacity, worse NYHA functional class, and lower KCCQ scores. Conclusions Adults with d-TGA following atrial switch have lower exercise capacity, reduced sRV systolic function, and greater mental health burden than adults with ccTGA. These findings support integrated assessment of physiologic performance, functional status, and mental health in adults with sRV physiology.

Background: Growth differentiation factor 15 (GDF-15) has emerged as a prognostic biomarker in patients with non-ST-segment-elevation acute coronary syndrome (NSTE-ACS). Our study evaluated the temporal evolution of GDF-15 in the acute phase and its association with recurrent ischemic events. Methods: Serum samples were collected from patients with NSTE-ACS at admission and at 1 and 3 hours after admission. GDF-15 levels, along with other prognostic biomarkers, NT-proBNP and hs-cTnT, were measured. Spearman rank-correlation coefficients and linear regression models were used to identify the variables associated with GDF-15 levels at admission and with their temporal changes. Associations between GDF-15 and clinical outcomes were evaluated using Cox proportional hazards models. To assess incremental prognostic value, the areas under the curve (AUC) were calculated for each model. Results: GDF-15 levels showed a slight increasing trend within 3 hours of admission. The 1-hour change in GDF-15 was correlated with hs-cTnT changes. Increased 1-hour GDF-15 levels, compared with the admission levels, were associated with a higher risk of recurrent ischemic events during the 1-year follow-up (1.9% vs. 17.5%, P =0.019) and were an independent predictor after adjusting for established clinical variables and biomarkers (adjusted hazard ratio, 1.71 (1.28 to 228.75), P =0.03). Furthermore, serial measurements of GDF-15 provided additional prognostic information beyond traditional risk factors. Conclusions: Serial measurements of GDF-15 of NSTE-ACS patients provided independent and incremental prognostic value for predicting recurrent ischemic events. These findings support the potential utility of GDF-15 as a dynamic biomarker for early risk stratification in the acute management of NSTE-ACS.

Background: In obstructive hypertrophic cardiomyopathy, surgical myectomy is highly effective but carries a recognized risk of postoperative conduction disturbances. Percutaneous intramyocardial septal radiofrequency ablation (Liwen procedure) is a less invasive alternative, but head-to-head comparisons of longitudinal hemodynamic trajectories and conduction system safety remain scarce, limiting evidence-based treatment selection. Methods: This single-center retrospective cohort included 211 patients treated 2018?2023 (124 Liwen, 87 modified Morrow myectomy). The primary longitudinal analysis included 133 patients with 1-year follow-up and serial data (75 Liwen, 58 modified Morrow myectomy). Repeated outcomes were analyzed using linear mixed-effects models and generalized estimating equations, adjusted for baseline covariates. Results: Both procedures reduced LVOT gradient, but trajectories differed (interaction P=0.002). At 1 year, the covariate-adjusted mean LVOT gradient remained higher after Liwen than after myectomy (16.1 vs 1.3 mmHg, P<0.001). However, the adjusted 1-year predicted probability of new conduction abnormalities was markedly lower after Liwen (5% vs 62%, P<0.001), with no permanent pacemaker implantations in the Liwen group. Most patients achieved gradient <30 mmHg in both groups (82% vs 96%; nominal P=0.308). Liwen had shorter procedure duration (80 vs 185 min) and hospital stay (11 vs 16 days). Serious adverse event rates were similar (8.1% vs 9.2%) but profiles differed. Conclusions: Modified Morrow myectomy achieved more complete LVOT gradient reduction at 1 year, whereas Liwen ablation had fewer conduction abnormalities, shorter procedure duration, and shorter hospital stay. These findings highlight a clinically relevant trade-off between more complete hemodynamic relief and lower conduction-system injury and require prospective confirmation.

Background: High-sensitivity cardiac troponin (hs-cTn) assays enable safe early discharge of patients at very low risk for myocardial infarction. We previously developed a single-sample rule-out pathway using the ARCHITECT hs-cTnI assay to risk stratify patients with suspected acute coronary syndrome. In a secondary analysis of the POC-ET (Point of Care Evaluation of High-sensitivity Cardiac Troponin) study, we evaluated performance of risk stratification with the Alinity hs-cTnI assay. Methods: Patients presenting with possible myocardial infarction in the POC-ET (NCT05665127) study were included. The primary outcome was type 1, 4b or 4c myocardial infarction or cardiac death at 30 days. Cardiac troponin I (cTnI) was measured in stored materials using the ARCHITECT and Alinity hs-cTnI assays. The sex-specific 99th percentile upper reference limit (URL) are 34 ng/L in men and 16 ng/L in women for both assays. Agreement was assessed with Bland-and-Altman limit of agreement method, Passing Bablok regression, and Pearson's correlation coefficient. Distributions of presentation measurements were compared with Kolmogorov-Smirnov test. Performance was evaluated in the overall population and prespecified subgroups. The negative predictive value (NPV) and sensitivity were determined and proportion of patients identified as low, intermediate, and high risk were calculated and modelled using ordinal logistic regression. Results: In 986 patients (60 [51-70] years, 38% female), 78 (7.9%) had a primary outcome. Strong agreement was found in the raw cTnI measurements (99% samples within the Bland-Altman limit of agreement; correlation coefficient r: 0.967 (95% CI 0.964-0.969, P<0.001); Passing Bablok regression: slope 1.12 [1.11-1.13], intercept -0.16 [-0.18 to -0.13]). At presentation, distributions of cTnI measurements by the two assays were similar (P=0.810). Both assays showed comparable diagnostic performance using a risk stratification threshold of <5 ng/L and the sex-specific diagnostic threshold, with the same NPV (Alinity 100 [99.7-100]% versus ARCHITECT 100 [99.7-100]%) and sensitivity (Alinity 100 [97.3-100]% versus ARCHITECT 100 [97.3-100]%). Similar proportions of patients stratified as low- (Alinity 67% versus ARCHITECT 67%), intermediate-risk (23% versus 24%) and high-risk (10% versus 9%) at presentation with minor reclassification. Similar efficacy was observed across subgroups stratified by sex, age, history of myocardial infarction, renal function, and symptom duration. Conclusions: The Alinity hs-cTnI and the ARCHITECT hs-cTnI assays can be used interchangeably in the assessment of suspected myocardial infarction with comparable safety and efficacy.

Background: Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous syndrome, and patients with a small left ventricular (LV) volume phenotype exhibit greater preload dependency. Whether the association between persistent outpatient oral loop diuretic use and clinical outcomes differs by LV volume phenotype remains unclear. Methods: We conducted a retrospective single-center cohort study of consecutive patients with heart failure and an LV ejection fraction [&ge;]50% who underwent transthoracic echocardiography between 2009 and 2024. Patients were stratified by LV volume phenotype using sex-specific LV end-diastolic volume index cutoffs. Associations between outpatient oral loop diuretic use and HF hospitalization, worsening renal function, and all-cause death were evaluated using multivariable time-varying Cox proportional hazards models, including interaction testing by LV phenotype. Results: Among 12,748 eligible patients, 1,437 had a small LV phenotype and 11,311 had a normal LV phenotype. Patients with a small LV phenotype initiated outpatient oral loop diuretics earlier and more frequently than those with a normal LV phenotype, while maintenance doses were comparable between groups. Outpatient oral loop diuretic use was associated with HF hospitalization in both phenotypes, with a significantly stronger association in the small LV group (hazard ratio [HR], 2.52; 95% confidence interval [CI], 1.68-3.78) than in the normal LV group (HR, 2.10; 95% CI, 1.77-2.49; P for interaction = 0.001). No significant interaction by LV phenotype was observed for worsening renal function or all-cause death. Fine-Gray competing-risk analyses showed a consistent interaction pattern. Conclusions: Persistent outpatient oral loop diuretic use was more strongly associated with HF hospitalization in patients with a small LV phenotype than in those with a normal LV phenotype. LV volume phenotype may help identify patients who warrant closer monitoring and more individualized diuretic management.

Background: Mitral valve prolapse (MVP) causes mitral regurgitation (MR), leading to volume overload and maladaptive left ventricular (LV) remodelling. Objective: To comprehensively characterize markers of maladaptive LV remodelling across MR severity grades in MVP using cardiovascular magnetic resonance (CMR), and their association with functional status. Methods: Patients with MVP undergoing 1.5T CMR (2016-2025) were stratified by MR fraction: mild<20%, moderate 20-39%, and severe [&ge;]40%. Exclusion criteria were significant coronary artery disease, rheumatic valve disease, mitral stenosis, previous mitral valve procedures, endocarditis or signs of primary cardiomyopathy. Global native T1, T2, extracellular volume (ECV), indexed ECV (iECV), indexed intracellular volume (iICV), and late gadolinium enhancement (LGE) were quantified. Indexed LV end-diastolic volume (EDVI) and the EDV-to-LV mass ratio (EDV/LVM-ratio) were also calculated as indices of LV remodelling and adaptive hypertrophy. Functional status was assessed by NYHA class. Results: Among 112 MVP patients (23 mild, 48 moderate, 41 severe MR) and 20 controls, LGE prevalence (17% vs. 46% vs. 51% vs. 0%) and the proportion with LV dilatation (46% vs. 67% vs. 88% vs 15%) rose progressively with MR severity. Increased EDVI, prevalence of LGE, higher EDV/LVM-ratio, global native T1 and iECV showed the strongest associations with more severe MR, whereas EDV/LVM-ratio, iECV and global native T1 were independently related to NYHA class[&ge;]II. Conclusions: CMR markers of maladaptive LV remodelling were abnormal across all MR grades and increased markedly with MR severity. Global native T1, iECV and EDV/LVM-ratio correlated most strongly with symptom burden, rather than MR severity per se.

Background: Pacing-induced cardiomyopathy (PICM) is a major complication of chronic right ventricular pacing and develops in up to 25% of patients. Reliable prediction of PICM may facilitate individualized pacing strategy selection; however, currently available approaches demonstrate limited discriminative performance. This study aimed to develop and validate machine learning (ML) models for predicting PICM in patients with atrioventricular block (AVB) underlying heart failure with mildly reduced or preserved ejection fraction. Methods: In this multicenter prospective study derived from the RISK-PICM registry (January 2002 to January 2026), 125 patients with AVB who underwent pacemaker implantation were analyzed. PICM was defined as a ?10% reduction in left ventricular ejection fraction (LVEF) resulting in an LVEF <50%. Four ML algorithms, including logistic regression, support vector machine, random forest, and XGBoost, were trained using stratified 4-fold cross-validation with hyperparameter optimization and model discrimination was evaluated. Results: PICM developed in 41 patients (32.8%) during a median follow-up of 4.8 years. Male sex, pre-implant minimum QTc interval, and post-implant maximum QRS duration were significantly associated with PICM in univariable Cox regression. XGBoost achieved the highest discriminative performance (AUROC 0.831; sensitivity 0.805; specificity 0.845). Feature importance analysis identified baseline LVEF and post-implant maximum QRS duration as the most influential features. Model-derived risk stratification significantly differentiated high-risk and low-risk groups on Kaplan-Meier analysis (P < 0.001). Conclusions: ML-based models, particularly XGBoost, demonstrated clinically meaningful performance for PICM and may support individualized pacing strategy selection in patients with AVB and underlying heart failure with mildly reduced or preserved ejection fraction.

Background: Mitral regurgitation (MR) is a common complication of mitral valve prolapse (MVP) and increases left ventricular (LV) preload, promotes LV remodeling and hypertrophy, but its impact on myocardial perfusion and coronary microvascular dysfunction remains unclear. Objectives: To assess myocardial perfusion using, for the first time, quantitative cardiac magnetic resonance (CMR) perfusion mapping in patients with significant MR due to MVP. Methods: Patients with significant primary MR, without coronary artery disease were prospectively enrolled and compared to age- and sex-matched controls without MR. All underwent 1.5T CMR including cine imaging, adenosine stress perfusion, native T1, native T2, extracellular volume (ECV) mapping and late gadolinium enhancement (LGE). Myocardial perfusion reserve (MPR) was calculated as the ratio of stress to rest myocardial perfusion. Results: In total 33 patients and 33 controls were included (age 56{+/-}13 vs. 58{+/-}12 years, 46% women in both groups). Patients with MR had increased LV mass and volumes, higher native T1 and ECV and a higher prevalence of LGE (36% vs 0%). No differences were observed in global myocardial perfusion at rest (0.88{+/-}0.27 vs. 0.85{+/-}0.30, p=0.52), at stress (2.6{+/-}0.56 vs. 2.8{+/-}0.73 ml/min/g, p=0.29) or for MPR (3.1{+/-}0.75 vs. 3.4{+/-}1.0, p=0.24). In age- and sex-adjusted linear regression, higher NYHA class was associated with lower MPR (0.60, p=0.04). Conclusion: In patients with significant MR due to MVP, myocardial perfusion appears preserved despite LV volume overload. However, lower MPR in symptomatic patients suggests that microvascular dysfunction may emerge in a more advanced disease stage.

Background: Although prophylactic veno-arterial extracorporeal membrane oxygenation (VA-ECMO) may provide hemodynamic stability during high-risk percutaneous coronary intervention (PCI), it is also associated with potential complications and may not be necessary in most cases. In this context, we proposed a pre-cannulated standby ECMO strategy and designed the ECMO-READY trial to evaluate the comparative effectiveness of pre-cannulated standby versus prophylactic ECMO strategies in patients undergoing high-risk PCI. Methods: The ECMO-READY trial is a prospective, multicenter, open-label, randomized controlled trial conducted in 8 sites in China. A total of 176 patients scheduled to undergo high-risk PCI will be randomly assigned in a 1:1 ratio to either a pre-cannulated standby ECMO strategy or a prophylactic ECMO strategy. The primary outcome is the 30-day incidence of major adverse events, including death, myocardial, infarction, repeat revascularization, stroke, PCI failure, limb ischemia, major bleeding, vascular injury requiring intervention, and need for renal replacement therapy. Secondary outcomes include post-procedural hemoglobin decline, post-procedural platelet count decline, red blood cell transfusion rate, peak post-procedural interleukin-6 level, use of intra-aortic balloon pump, duration of ECMO support, length of hospital stay, hospitalization cost, and each component of the composite primary outcome. Enrollment began in March 2025 and is anticipated to be completed by December 2026. Discussion: The ECMO-READY trial will provide prospective randomized evidence regarding ECMO support strategies in patients undergoing high-risk PCI and may help inform future clinical practice. Trial registration: ClinicalTrials.gov NCT06274411. Registered on February 23, 2024. Keywords Percutaneous coronary intervention, High-risk, Extracorporeal membrane oxygenation, Ready, Standby, prophylactic, Major adverse events

Background: This study aimed to determine the prevalence of BBB, characterize associated clinical and echocardiographic phenotypes, and evaluate associations with incident cardiovascular diseases and all-cause mortality in the general population. Methods: We analyzed 12-lead electrocardiograms from 14,212 subjects from the Hamburg City Health Study (45-74 years). BBBs were defined using Minnesota Code criteria. We applied elastic net regularization to identify clinical associations, and multivariable Cox models for outcome analyses. The total cardiovascular outcome included all-cause mortality, incident heart failure, myocardial infarction, atrial fibrillation, pulmonary embolism, and stroke. Results: Complete left (cLBBB) and right (cRBBB) bundle branch blocks were prevalent in 0.8% and 2.3% of subjects, respectively. Subjects with complete BBB were generally older with a higher burden of cardiovascular risk factors and comorbidities, cLBBB additionally showed higher N-terminal pro-hormone of brain natriuretic peptide levels. The main predictor of BBB was age. Male sex was an additional predictor for cRBBB, while hypertension, hypercholesterolemia, and reduced left ventricular ejection fraction predicted cLBBB. Both, cLBBB and cRBBB were associated with a reduced left ventricular ejection fraction, increased septal wall thickness, and left atrial enlargement. cRBBB demonstrated right ventricular dilation, whereas cLBBB showed markedly impaired left atrial strain. In adjusted analyses, both BBBs were associated with the total cardiovascular outcome (cLBBB: hazard ratio [HR], 2.71; 95% confidence interval [CI], 1.68-4.39; p<0.001; cRBBB: HR, 1.52; 95% CI, 1.09-2.12; p=0.01). Although both were significantly associated with incident heart failure, myocardial infarction, and atrial fibrillation, cLBBB uniquely was associated with all-cause mortality, whereas cRBBB distinctly was associated with incident stroke. Conclusion: In the general population, BBB is a high-risk phenotype characterized by subclinical cardiac alterations and a markedly worse long-term outcome. These findings underscore the importance of early risk stratification. Proactive clinical management in otherwise asymptomatic individuals presenting with these conduction disturbances should be considered.

Background: Atrial fibrillation (AF) has been observed in adults with anomalous pulmonary venous return (APVR), but data on catheter ablation outcomes in this population remain limited to case reports and small series. Methods: We retrospectively reviewed 14 adult patients with confirmed APVR who underwent catheter ablation for AF at three tertiary academic centers in the United States between July 2003 and May 2025. Baseline, procedural, electroanatomic mapping, and outcome data were collected. Freedom from atrial arrhythmia recurrence was estimated by Kaplan-Meier analysis. Results: Mean age was 56 +/- 13 years and 79% were male. Heart failure was present in 64%, and hypertension and coronary artery disease in 43% each. Most had partial APVR (86%), and 57% had prior surgical correction. Radiofrequency ablation was used in all patients, combined with pulsed-field ablation in one. Acute success was achieved in all patients, although areas with residual pulmonary vein or SVC electrical activity were left untreated in 3 (21%). Non-pulmonary-vein electrical activity was more common in patients with prior surgical correction than in those without (43% vs 17%). Median follow-up was 3.4 years (IQR, 2.0-9.6). Freedom from arrhythmia recurrence was 78.6% at 1 year and 53.9% at 5 years. Two patients (14%) required reablation; complications occurred in 3 (21%) without long-term sequelae. Conclusions: Catheter ablation was acutely successful in all patients in this largest reported APVR cohort, despite substantial comorbidity burden and anatomic complexity. The arrhythmogenic substrate often extended beyond the anomalous vein, particularly in surgically corrected patients, supporting individualized, substrate-guided ablation in this population.

Background. Durable mitral isthmus (MI) block remains challenging in persistent atrial fibrillation (PeAF) ablation. Recent epicardial vein of Marshall (VoM) recordings have shown incomplete MI transmurality and time-dependent conduction recovery after pulsed field ablation (PFA). Whether systematic VoM ethanol infusion (VoM-EI) followed by focal PFA provides stable acute MI block remains unknown. **Objectives.** To assess the incidence, timing, and procedural implications of early MI conduction recovery after systematic VoM-EI followed by focal Sphere-9 PFA. Methods.In this prospective single-center study, 55 consecutive patients undergoing first ablation for symptomatic PeAF with planned MI ablation were screened. VoM-EI was systematically attempted before left atrial access and successfully performed in 51 (92.7%), who constituted the study cohort. Pulmonary vein isolation, roof-line, and MI ablation were performed with the Sphere-9? lattice-tip catheter. After bidirectional MI block, conduction was systematically reassessed during a standardized 30-minute waiting period. Results.Mean age was 70.3 {+/-} 8.2 years, and 36 patients (70.6%) were men. Initial bidirectional MI block was achieved in 50/51 patients (98.0%). During the waiting period, conduction recovered in 9/50 (18.0%; 95% CI, 9.8%-30.8%), at a median of 16 minutes (IQR, 10-20; range, 8?23). Six of 9 patients with recovery (66.7%) required targeted coronary sinus (CS) ablation. Block was restored in all 9, yielding a final block rate of 50/51 (98.0%). Median procedure duration was 82 minutes (IQR, 73-95), with no major complications. Conclusions. Immediate bidirectional MI block was not synonymous with stable block. Despite systematic VoM-EI followed by focal Sphere-9 PFA, conduction recovered in approximately one in five patients, including beyond 20 minutes, and two thirds required targeted CS ablation. These findings support standardized 30-minute reassessment and targeted CS interrogation rather than reliance on immediate block. Chronic invasive remapping is required to determine whether this strategy improves long-term MI block durability.

Background: Vagally mediated syncope and functional bradyarrhythmias can cause recurrent symptoms, injury and a need for permanent pacing, yet standard therapies do not address the underlying autonomic reflex. Cardioneuroablation (CNA) targets this mechanism, but adoption has been limited by uncertainty about patient selection, procedural endpoints and durable outcomes. Methods: We studied 95 consecutive patients with vagally mediated syncope (n=78) or functional bradyarrhythmia (n=17) who underwent CNA at a single center by a single lead operator under a uniform, prospectively maintained protocol. Extracardiac vagal stimulation (ECVS) was performed before and after ablation to confirm vagally mediated sinus or atrioventricular (AV) nodal responses and to verify their attenuation. Outcomes through 1 year included clinical recurrence, quality of life, pacing burden and pacemaker extraction. Results: Before ablation, ECVS provoked sinus pauses in 95.8% of patients and AV block in 91.6%; after ablation, sinus pauses were abolished in every patient and residual AV block was present in 4.2%. One-year freedom from recurrent syncope and from bradyarrhythmia-related events was 93.8% and 94.1%. Syncope burden fell from a median of 2.7 episodes per year to none, and disease-specific quality of life improved substantially (P<0.001). Among patients with pre-existing devices, atrial pacing burden fell from a median of 22% to 0%. There were no strokes, deaths or myocardial infarctions. Conclusions: In this single-center cohort, physiology-guided CNA was associated with durable symptom control, improved quality of life and reduced pacing across vagally mediated bradyarrhythmia syndromes. Multicenter controlled studies are needed to confirm these findings.

Condensed Abstract: Using the 2016?2022 National Inpatient Sample, this study evaluated temporal trends and demographic adoption patterns of percutaneous left atrial appendage occlusion (LAAO). Among 190,020 weighted procedures, annual volume increased from 4,875 to 60,445. In-hospital mortality was exceptionally low (0.1%). Age-adjusted procedural rates rose from 34.19 to 379.87 per 100,000 population. However, significant disparities persisted, characterized by heavy centralization in urban teaching hospitals (87.0%) and disproportionately lower absolute age-adjusted utilization among female, Black, Hispanic, and Asian/Pacific Islander patients compared to male and White cohorts. Targeted initiatives are needed to ensure equitable access to structural heart interventions.

Introduction. Extracorporeal cardiopulmonary resuscitation (ECPR) can support patients who fail to respond to standard resuscitation for out-of-hospital cardiac arrest (OHCA) allowing further time for critical interventions and patient recovery. Although the majority of patients with refractory OHCA have coronary artery disease, the role of emergent percutaneous coronary intervention (PCI) is not clear. We evaluated the effect of PCI on survival to hospital discharge (SHD) in a contemporary cohort of patients with OHCA receiving ECPR. Methods. We performed a retrospective study using data from the Extracorporeal Life Support Organization (ELSO) registry. We included patients ?18 years with OHCA due to a presumed cardiac etiology or an initial shockable rhythm who received ECPR from January 2020 to December 2023. Our primary outcome was SHD. We used inverse probability weighted matching to estimate the average treatment effect of PCI on SHD. We also performed a sensitivity analysis of patients most likely to benefit from PCI (witnessed arrest and no return of spontaneous circulation after five minutes of cardiopulmonary resuscitation. Results. Of 1336 OHCA patients receiving ECPR, 1131 were included in the final analysis after exclusions for age (n=31) and presumed non-cardiac or initial non-shockable rhythm (n=174). The median age was 55 years (IQR 44-62) and most patients were male (n=901, 80%). Twenty-one percent (n=243) received PCI; those patients who received PCI were slightly older (58 [IQR 48-63] vs 53 [IQR 42-62]) and more often male (n=212 [87%] vs n=689 [78%]). In the primary analysis, we found no significant difference in SHD for patients who received PCI compared to those who did not receive PCI (-3.56%, 95% CI -10.31 to 3.19; p-value 0.301). In our sensitivity analysis, we also did not find a significant difference in SHD for patients who received PCI compared to those who did not receive PCI (-4.52%, 95% CI -12.42 to 2.46; p-value 0.246). Conclusion. In our registry-based study of refractory OHCA patients receiving ECPR, emergent PCI was not associated with a significant improvement in SHD.